does anyone have OI and RC radio issues

[waialua359]

Hi all,
We hooked up our drivetrain with the OI and RC complete. As we were testdriving our robot so far, we noticed that the radio would go to "no communication" mode and the controllers were basically dead and not controlling the robot. It is intermittent.
anyone have issues or solutions with this problem?

[Al Skierkiewicz]

When the radio doesn't work, the first response should be to tether up and see how things go. If that does not work then you can start to troubleshoot wiring errors, team number settings, dead batteries, etc.

[Ian Curtis]

When the radio doesn't work, the first response should be to tether up and see how things go. If that does not work then you can start to troubleshoot wiring errors, team number settings, dead batteries, etc.

It's not that the radio just loses connection but that the user loses control. Even the disable switch doesn't work. It's my understanding that if the robot loses contact with the OI it should disable itself. It doesn't. The user simply loses control for a short while.

[mcurtis]

We also experienced this. At the time, we were running the 2006 OI. Robot seems to be locked in the last data packet sent by the OI. Tonight we will continue testing with 2007 OI to replicate the problem. Because the robot thinks it has good data, disable switch does not work, leading to a very dangerous situation. It seems to happen for a matter of seconds, and return to normal operation. Because of the short duration, and random nature, haven't been able to read the diagnostic lights on the OI. It has not occured with the tether cable.

Maynard

[Mike Betts]

I strongly suggest that you report this problem to IFI.

[Alan Anderson]

It's not that the radio just loses connection but that the user loses control. Even the disable switch doesn't work. It's my understanding that if the robot loses contact with the OI it should disable itself. It doesn't. The user simply loses control for a short while.
This sounds similar to last year's "8.2 volt" bug. It never bit us, so I didn't pay close attention to the prescribed fix. I think it involved modifying the linker script to make a bank of memory out of bounds. If nobody pipes up with a good pointer to the details, you can search the forums.

[mcurtis]

I believe it's a problem with the communications. With the 8.2 problem, I didn't see any reference to the disable switch failing. We were using the 2006 OI with the new radios, so it may be a change in the radio communications which causes a intermittent problem. I have notified IFI of the situation. We have the new libs, and linker file installed.

Maynard

[Spider-Man]

Have you updated the Master Code on the 2006 RC?

I believe that the new V13 master code for 2007 has changes for the new radio.

[Eldarion]

This sounds similar to last year's "8.2 volt" bug. It never bit us, so I didn't pay close attention to the prescribed fix. I think it involved modifying the linker script to make a bank of memory out of bounds. If nobody pipes up with a good pointer to the details, you can search the forums.

Yes, that sounds very familiar! :ahh:

Also, for those who think the problem may be completely unrelated to the 8.2v bug, remember that when you corrupt a section of memory on a running computer program, the results are (almost) completely unpredictable. A section of memory that is receiving data from the OI may be being corrupted, thereby locking in the last data frame instead of shutting down due to lost radio link.

I wonder if this may be a problem peculiar to your RC, only time will tell.

[mcurtis]

It's the 2007 RC, which I believe has v13 master. Waiting for a return call from IFI. Were getting a "no radio" on the OI. Shouldn't this cause the master to shut down, regardless of what the User processor is doing?

[Gamer930]

It's the 2007 RC, which I believe has v13 master. Waiting for a return call from IFI. Were getting a "no radio" on the OI. Shouldn't this cause the master to shut down, regardless of what the User processor is doing?

Correct, "no radio" should immediately stop the robot dead in its tracks.

Does it work fine tethered??

[mcurtis]

Spoke with the fine people at IFI. Best guess is it's either a bad cable, or interference from another radio source. There is a half second delay after the last good packet before the robot shuts down. After a good packet is received, the counter is reset, causing an additional half second delay. Hopefully we can narrow it down tonight.

Gamer930,
We have not seen it happen with the robot tethered. It only happens intermittently on the radio.

Maynard

[waialua359]

we were using the 2006 oi and rc with the new radio's from 2007. Is there a difference with the 2007 oi and rc? we are going to try and run tomorrow with using the 2007 oi and rc and see if there is a problem.
when we lose the radio signal on our oi, the robot stall and shows loss signal also.
cant see how it would be intereference. nothing else around and we have always tested in the same room.

anyone? please help.

[Alan Anderson]

we were using the 2006 oi and rc with the new radio's from 2007. Is there a difference with the 2007 oi and rc?
To the best of my knowledge, the 2006 and 2007 systems are identical hardware. But the 2007 RC came with v13 of the master code installed, which has specific support for the new radios. If you haven't yet updated the master code in your 2006 RC, that might be an issue.

(To check the master code version, press the mode button on the OI until it shows the 3-digit user value. The display will show the version number briefly before changing to the user byte value. You want to see u013 appear.)

[mcurtis]

We're still seeing this problem. After talking to IFI, we tried the following.

1) replaced both modem cables
2) tried using other channels
3) moved the rc modem away from power sources
4) switched to the 2007 OI (shouldn't make a difference)
5) loaded default code from IFI
6) disconnected the power on OI to test 1/2 sec timeout (passed)

Still seeing intermittent modem losses. We did discover the RC is losing the link first. Sometimes it recovers before the OI realizes there is a problem (never see a modem light on OI).

waialua359,
I suggest you contact IFI. It could be an unrelated issue, but it sounds very similar.

I'll call IFI again when the sun gets a little further west.

Maynard

[Al Skierkiewicz]

Maynard,
The condition you describe can be a power issue to the OI. Does the modem cut out when the robot is just sitting there or does it cut out when moving? There is also a possibility in antenna location and orientation. Is it possible to take a picture of the modem mounting without sacrificing team secrets? Is the radio mounted near a motor, particularly an FP or Mabuchi? Does the modem cable run near wiring that feeds any motors?

[mcurtis]

The modem was near the main breaker. We moved it away, but perhaps not far enough. What would you consider a safe distance. We're running four CIMS on modified AM gearbox. Although it's difficult to say for sure, it generally seems to be under power. However, it also happens with the robot on stands, with little load on the motors (free wheeling). Sorry, don't have access to the robot now, so can't provide pics. It's still in the prototype phase (controls screwed to plywood). We'll try moving the modem a greater distance tonight.

Maynard

[Al Skierkiewicz]

Maynard,
Being near the main breaker is usually not a problem, having the antenna itself near metal objects will detune the antenna and make it inefficent. Spark noise from the brushes can wreak havoc with the modem and usually unloaded motors produce more noise than normal loads so being up on blocks would produce as much or more problems than driving. It also may be the way the robot is wired. The power for the RC should come from the first breaker on the multi position breaker panel. Make sure that all connection to the RC are tight. Finally, and I should have mentioned this before, you need a fully charged Backup battery connected to the RC. The NiCads come discharged so you need to charge them at least ten hours out of the box. The backup holds up the radio modem during times the RC shuts down for low voltage.

[mcurtis]

Thanks for the help Al,

The modem is about one foot from one of the gear boxes. We'll try mounting it on a mast tonight. I'm quite sure our wiring is correct, but we'll double check it as well. We're servo shifting, so I am sure we have a charged backup battery.

Maynard

[Al Skierkiewicz]

It wouldn't coincide with the shift point would it? Are the servos having a hard time shifting? Try without shifting and see what happens.

[mcurtis]

We loaded the default code, which did not have our shifting code. The servos were unplugged and we simply drove back and forward in a straight line. A failure occurred with 30 seconds. We'll also try leaving the robot idle to see if we get the failure.

Thanks
Maynard

[waialua359]

To the best of my knowledge, the 2006 and 2007 systems are identical hardware. But the 2007 RC came with v13 of the master code installed, which has specific support for the new radios. If you haven't yet updated the master code in your 2006 RC, that might be an issue.

(To check the master code version, press the mode button on the OI until it shows the 3-digit user value. The display will show the version number briefly before changing to the user byte value. You want to see u013 appear.)

OK. I just checked the version and it is the u012 version. i used this years mplab to get the default frc code. how do i update to version 013. Does anyone know if its the reason it would cause radio, no modem failure?

[Bharat Nain]

We have experienced the same problem. Even after following all the rules and guidelines provided by IFI and some of you folks, our radio randomly decides to stop working, and sometimes the robot will still keep going for a while (Maybe half a second, but thats enough to break a few bones). Some folks reported the same problem at Ramp Riot where the newer radios were tested. I really hope IFI looks into this and corrects this problem. It would be extremely frustrating to have a bug stop us from programming to our fullest like last year.

[mcurtis]

Just got off the phone with IFI. There shipping us new modems to try.If your seeing occasional modem losses, be very careful. We lost control of the robot at 15 fps. While the robot is supposed to shut down after 1/2 second, ours traveled around 30 feet before it met it's first obstruction. As they say, "The rest is history".

Bharat
If you have any 06 modems, IFI said the should work with v13 master code.

Maynard

[Kims Robot]

We are having the same issue... We checked all the wiring, and its definitely the radio cutting out. I'll be interested to see what the results are.

I have to wonder if it has to do with the housing... the housing is far to large for the board as far as I can tell, and when you shake it a little, you can hear that it isnt braced much against the casing.

[mtaman02]

Now what happens if IFI determines it is the new radios or the whole RC kit to be defective. Will they ship new kits out to all teams or those with the problem. If they don't plan on shipping to the teams does that mean teams need to prolong the programming which usually is the last phase of building and pick up new kits when they get to their first regional? I have always known the lost of signal for the slightest amount of time was caused by power issues and interference, so I don't think it has to do with programming all though the simplest of things can cause the greatest of problems. Something to be kept up to date on. If i set up the 2007 Kit (RC & OI Stuff) and plug everything up would there be a chance of getting the same problem or does the RC need to have motors and such be attached before you see any radio issues?

[Bharat Nain]

Bharat
If you have any 06 modems, IFI said the should work with v13 master code.

Maynard

That's what the kids did. I am not sure of the results but I hope one of them can post about it here soon. I am assuming IFI will at least put more reliable modems at the competition, but for now, we must live with what we have. I am not sure how rookies will take this as they have no older modems. Autonomous programming and testing purely on a tether is kind of hard.

[waialua359]

wow! and I thought we only had this problem. Im surprised it didnt come up earlier with a lot of other teams. I guess we are lucky to have a drivetrain already with some functions.
Anyways, its confirmed that when we use our 05 or 06 radios, our 2007 robot works! But by only changing to the new 07 radios, it shuts down intermittently!
can someone confirm that the u013 code will work even with the older 05,06 radios. I didnt want to upgrade, only for it to not work. If that were to happen, then we would be stuck with using the new radios that dont really work well right now.

Thanks in advance!!:D

[mcurtis]

According to IFI v13 should work fine with 06 modems, and I believe 05 are the same.

Great to hear it solved your problems. We haven't tried the old modems yet.

Maynard

[waialua359]

IFI is sending us new tested radios for us to see if they work properly on our robot. Cory was gracious enough to do this free of cost.
We are sending our old ones back.
This is a request similar to team 1276 also.

[waialua359]

its now confirmed 100% that our radios are having issues. IFI has not posted an answer to my question yet because they are still investigating the issues.
If anyone has similar problems, please post.

Thanks,
Hawaiian kids

[mcurtis]

We should get our radios today. IFI has been great to deal with and very responsive. Sure makes a difficult situation a little easier.

Maynard

[waialua359]

IFI told me this morning that they will want to investigate your radios when you send them back. We are sending ours back already also.

[mtaman02]

Ok I have a few questions and maybe I should post them on IFI's Forums but I'll give here a shot first:

1) All though a few teams have come forward and made the rest of us aware of the OI & RC Modem problems - Does this effect all the teams radios?
2) Is there a way to find out if your OI & RC Modem is defective by just plugging everything in as far as joystick or 2 / power / maybe a speed controller & a victor - Basically not setting up completely but enough to get everything talking and making everything look like its under joystick control or does the control system need to be completely setup?
3) Should teams just go and contact IFI and talk with their representatives under the assumption that the OI & RC Modems are defective w/o actually hooking everything up and finding out first.

[Aidan F. Browne]

Ok I have a few questions and maybe I should post them on IFI's Forums but I'll give here a shot first:

1) All though a few teams have come forward and made the rest of us aware of the OI & RC Modem problems - Does this effect all the teams radios?
2) Is there a way to find out if your OI & RC Modem is defective by just plugging everything in as far as joystick or 2 / power / maybe a speed controller & a victor - Basically not setting up completely but enough to get everything talking and making everything look like its under joystick control or does the control system need to be completely setup?
3) Should teams just go and contact IFI and talk with their representatives under the assumption that the OI & RC Modems are defective w/o actually hooking everything up and finding out first.

Team Update #6 seems to address your concerns -- looks like IFI is working on it.

[mtaman02]

Team Update #6 seems to address your concerns -- looks like IFI is working on it.

Ahh see this is the end result of me not keeping up on the team updates thanks for pointing that out i'll go ahead and download the update

[waialua359]

As of now, of the 4 teams participating in Hawaii, Team 368 has also tested out their RC and OI with the new radios. After talking with them last night, they have not encountered any problems with the radios so far.
It seems that since there has not been too many teams posting problems here, they either havent tested them yet, have no problems with them, or havent read this post.

Can anyone who has tested their 2007 radios post if they DO work OK?:D

[Racer26]

Well, I have my own comment to add to this issue.

1075 got the 07 system set up on a bot tonite, and I IMMEDIATELY noticed alot of lag in the system... soon after that, i realized it was the radio cutting out on me. Sounds EXACTLY like what you're saying, the Master chip isn't shutting the bot down on radio loss... this is rather distressing to take your hands off the controls and the robot doesn't stop.

Our first thought laid the blame with our placement of the radio... it is within a few inches (read 4-6") of two CIM motors. After reading this, I think maybe the blame needs to be laid on the v13 master code, or the new radios.

Edit: We were using the 07 RC / 07 OI / 07 Radios

[waialua359]

I really dont think its the master code. we encountered the problems with the older u012 and u013 codes alike. We used three different robots, including this year's robot base and tried all the likely scenarios to try and pinpoint the source of the problem, including orientation, location, etc. the new master code worked perfectly with our old radios also. Unless, the new master code is geared towards the old radios??

[waialua359]

Our FCC ID for our RC is UKU-RC01.
Our FCC ID for our OI is UKU-OI01.

[finni]

fcc exibits on the lisence
OI. Modem https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=606267&fcc_id='UKU-OI01' (https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=606267&fcc_id=%27UKU-OI01%27)

RC. modem
https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=642706&fcc_id='UKU-RC01' (https://gullfoss2.fcc.gov/prod/oet/cf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=642706&fcc_id=%27UKU-RC01%27)

[generalsnipe]

we have a problem with our oi and rc, i got it to connect and we were all happy, but when we went to power it back up, it just didnt want to work. ifi has not posted anything yet about the problem but i hope they fix it, the robot workes in teather mode

[mcurtis]

Ran the replacement modems today for nearly an hour without any failures. With the original modems we never went longer than 10 minutes with out a loss of signal. While we still need to test them further, it's very encouraging.

Maynard

[roboticsguy1988]

Team 1501 is also having the same problem. We have already experienced things like the disbale not wokring when it should etc. When it was first rbought to my attention and i was testing it we let go of the joysticks and the robot did not stop until it scooted a table a good 2 feet or so.

We usually try to have extra radio modems, victors, and spikes, so when the radio modems come in we will switch them out and see what happens.

*EDIT
I wanted to add that, we had a problem simular last year. We had came to the conclusion that it was static electricity coming through a custom cable. Once the cable was removed off the robot, we didn't have the problem again.

I have also seen (as mentioned elsewhere in this thread) the robot do this when the backup battery gets low. I did not think of the frame and the antenna being close together as causing a problem, but will check on that.

So far we have tried a bunch of things. While it has only happened a few times, when it does happen it goes on for a little bit. I think the last time I seen a problem was 2 or 3 days ago

*EDIT

[waialua359]

I hope we get the new ones today so we can test them out.

Maynard-is your radios still working without problems?

We will post whether our new radios work once we get them.

[mcurtis]

It was Saturday we tested them, and we did not meet Sunday. Not sure how much we will run them tonight. We spent over two nights trying to resolve the problem before we got replacements, so we're playing catch up. I'll let you know how it goes.

I shipped the old modems back today.

Maynard

[MishraArtificer]

From another thread on this subject...
While attempting to fix this problem, we may have accidentally stumbled over the answer. Our cell phones appear to be interfering with the signals between the radios. Try placing your cell phone near the radio and calling it, and see if this causes the interference. The "random" timing of the interruption may be the cell phones reconnecting to their respective service towers.
Any merit?

[Fireworks 234]

I am not sure how many people are having problems with the OI and RC, but from what I can tell we are one of the few unlucky ones. I think we will be contacting IFI soon about our glitches. Namely, the robot running several seconds after it drove into our makeshift player station. It's nice to see that they are doing something about this though.

Good Luck to all of you and I hope that not everyone is affected on this one.

[waialua359]

cell phones are not the issue that's for sure. However, we have yet to try our new radios yet since we were powdercoating parts of our robot.
We will try it today and see if IFI has fixed our problem.
Again, I will keep it posted once we find out.

[RyanN]

I wonder if this problem only affects random radios, or if it's every single radio.

[esquared]

Team 1511 has experienced the OI/RC radio issues as well for the past 2 weeks. Same symptoms of cutting in and out for a period of a few seconds, as well as the master disable switch on the competition port NOT killing the robot as it should.

I contacted IFI over this past weekend, and spoke with Corey Chitwood, who was extremely helpful. We had a discussion regarding potential RF interference issues, internal vs. external antennas, and we tried a few of his suggestions. From our discussion on Saturday morning, there is not a mass recall or swarm of teams reporting problems (yet). He mentioned the teams who have posted above this, and said that they found and fixed a clear hardware problem on the very first team to have sent their radio back. At that time, he had not received the other radios that were RMA'd, and couldn't provide any additional info.

We tested extensively on Saturday and Sunday, both in autonomous and manual drive modes, and continued to experience radio cutouts. After nearly squashing a mentors foot with a speedy autonomous (and un-killable) robot, we reverted to last years radios. I obtained a RMA from IFI on Tuesday afternoon, and our modems ship out Thursday morning.

When we receive our new ones I'll post an update regarding their performance.

--Eric

[roboticsguy1988]

Well, our team has not yet contacted IFI, since we usually order an extra set of radio modems we were going to wait to see if those worked. But they have been out of stock for quite a while. Our problem from what i have seen and heard does not happen all the time it is quite random. But having a robot with no control even for a few seconds can be bad.

I'll post if i have any news

[billbo911]

We decided to do a double process tonight. We broke in our transmissions and tested our modems. We had the controller on one side of the class room and the RC on the other.
We used the trim on one joystick to drive both motors via the "single stick" drive mode.
Randomly the motors would just stop and restart, indicating that the data comm. had dropped for a sufficient amount of time to cause a timeout. While observing the RC, it became obvious that the Radio Modem light would flash RED when ever the motors would stop.

We will be contacting IFI in the morning to report the problem and await further instructions.

[Al Skierkiewicz]

cell phones are not the issue that's for sure. However, we have yet to try our new radios yet since we were powdercoating parts of our robot.
We will try it today and see if IFI has fixed our problem.
Again, I will keep it posted once we find out.

While cell phones do not operate on the same frequency as the modems, they are capable of some high signal levels that could cause local inteference which could cause the radio modems trouble. It is one of the reasons that wireless communication is not allowed at the playing field.

From section 3.14.3 Pit and Competition Safety

Two-way radios: Not allowed in the Pit or near the playing field since they may interfere with robot operation and cause accidents.

[esquared]

While cell phones do not operate on the same frequency as the modems, they are capable of some high signal levels that could cause local inteference which could cause the radio modems trouble. It is one of the reasons that wireless communication is not allowed at the playing field.

From section 3.14.3 Pit and Competition Safety

Two-way radios: Not allowed in the Pit or near the playing field since they may interfere with robot operation and cause accidents.

If our new radios continue to have problems, I plan to run a poor man's RS103 test (1 V/m, 30MHz-9GHz) in a 3m shielded room to see if I can cause the problem to crop up at a specific frequency range. I might be able to push the field strength with some hacking up to 5 V/m from 1-8GHz, which includes the cell phone band.

For the interested reader, RS-103 is part of a battery of tests performed under MIL-STD-461D (the new E is very similar) for military qualification of electronic products. Commercial products rarely need to meet a susceptibility requirement, other than the generic FCC Part 15 statement for intentional radiators that says they "must accept any interference caused by the legal operation of other radio services".

I suspect no one is really interested in EMI though :( :(

[Al Skierkiewicz]

If our new radios continue to have problems, I plan to run a poor man's RS103 test (1 V/m, 30MHz-9GHz) in a 3m shielded room to see if I can cause the problem to crop up at a specific frequency range. I might be able to push the field strength with some hacking up to 5 V/m from 1-8GHz, which includes the cell phone band.
Esqaured,
The modems operate in the 918MHz FRC band. So most cell phone interference is from cell phones operating just under 900 MHz and obvious FRC radios and Ham operators in the adjacent band. I suspect you might find that interference is not as big a problem as the AGC overload caused by nearby signals forcing the input gain down.
Please check for EMI as well, I think it will prove to be useful data.

[esquared]

Esqaured,
The modems operate in the 918MHz FRC band. So most cell phone interference is from cell phones operating just under 900 MHz and obvious FRC radios and Ham operators in the adjacent band. I suspect you might find that interference is not as big a problem as the AGC overload caused by nearby signals forcing the input gain down.
Please check for EMI as well, I think it will prove to be useful data.

I should have been more specific in my previous post, the medium power amplifier I will try out has a spec'd frequency range of 1-8GHz, but continues to exhibit reasonable gain and output power specs for another 2-300MHz below it. The 5V/m is my best guess at effective radiated power at these "unspecced" frequency ranges.

You've got an excellent point about AGC (Automatic Gain Correction, which in RF systems is intended to avoid saturating your receiver, which leads to data that all looks like the same, far too high level). To test this, I'd have to crack the case on the modem, and somehow I doubt our team leader will go for this :ahh: Anyone void their warranty and see how they implemented this year's radio?

Another possibility: I've seen front-end bandpass filters that had poorer than expected rolloff outside the band, resulting in a susceptible front-end. Since the hardware repair to the first team's radio was relatively quick, replacement of a poor quality filter would fit into this category. Additionally, it may not be an issue with all filters, so some teams could be operating just fine.

In the end, I expect this to be similar to last year's 8.2V problem where some teams had it, some didn't. Very similar in that both resulted in non-responsive or potentially destructive robots!

[waialua359]

While cell phones do not operate on the same frequency as the modems, they are capable of some high signal levels that could cause local inteference which could cause the radio modems trouble. It is one of the reasons that wireless communication is not allowed at the playing field.

From section 3.14.3 Pit and Competition Safety

Two-way radios: Not allowed in the Pit or near the playing field since they may interfere with robot operation and cause accidents.

That's interesting. How about the old radios? Is there something in its makeup where cell phones dont have a strong enough signal to affect them.
I made that statement earlier based on an earlier post, then had our whole team use their cell phones near the robot with our old radios. It didnt encounter any loss signal between the OI and RC.
What's different internally with these new radios?

[Al Skierkiewicz]

E,
I kind of doubt there is great filtering on these radios due to the low cost of the item. My guess is the T/R filtering is about all there is with a little additional low pass to cut the 2nd harmonic down to spec. What we don't know at this point is how great the shields are inside and your testing might show that.

waialua,
We don't know enough about these radios yet to answer your questions. The reports of failures from teams on CD do not tell the whole story. There are far too many variables to point to one thing. Let's just hope that IFI will take care of this as they have in the past.

[Dave K.]

I should have been more specific in my previous post, the medium power amplifier I will try out has a spec'd frequency range of 1-8GHz, but continues to exhibit reasonable gain and output power specs for another 2-300MHz below it. The 5V/m is my best guess at effective radiated power at these "unspecced" frequency ranges.

You've got an excellent point about AGC (Automatic Gain Correction, which in RF systems is intended to avoid saturating your receiver, which leads to data that all looks like the same, far too high level). To test this, I'd have to crack the case on the modem, and somehow I doubt our team leader will go for this :ahh: Anyone void their warranty and see how they implemented this year's radio?

Another possibility: I've seen front-end bandpass filters that had poorer than expected rolloff outside the band, resulting in a susceptible front-end. Since the hardware repair to the first team's radio was relatively quick, replacement of a poor quality filter would fit into this category. Additionally, it may not be an issue with all filters, so some teams could be operating just fine.

In the end, I expect this to be similar to last year's 8.2V problem where some teams had it, some didn't. Very similar in that both resulted in non-responsive or potentially destructive robots!

Eric,

Pictures of the radio's internals are part of IFI's FCC OET, EA public file as is the emissions test report performed on a prototype unit.

Based on my own observations of the problem, an Electrical Fast Transients test, such as EN 61000-4-4, might be more revealing than an RF succeptability test, but certainly a lower frequency, 100% AM modulated signal can reveal problems that an EFT test would also expose.

Again, without motors running, we saw no indication of packet loss.

Our build location is surburban with no close field radiators, let alone any dynamic radio transmission that would be tightly coupled to motor actuations.

[waialua359]

Eric,

Pictures of the radio's internals are part of IFI's FCC OET, EA public file as is the emissions test report performed on a prototype unit.

Based on my own observations of the problem, an Electrical Fast Transients test, such as EN 61000-4-4, might be more revealing than an RF succeptability test, but certainly a lower frequency, 100% AM modulated signal can reveal problems that an EFT test would also expose.

Again, without motors running, we saw no indication of packet loss.

Our build location is surburban with no close field radiators, let alone any dynamic radio transmission that would be tightly coupled to motor actuations.

that just went right over my head??

[Dave K.]

that just went right over my head??

I appologize if some of my references or terminology was confusing to others. My intent was to respond to Eric's proposed test and to answer a question as to the 'what's inside' question.

Eric suggested that he was going to run some high(er) frequency RF succeptability testing, and I suggested that, based upon my observations, that the problem might be easier to expose by subjecting the device to lower frequency pulsed transients.

EN (EuroNorme) 61000 describes a number of different product compliance tests, and among them is a specific fast transient test where interconnecting cabling is laid in a coupling trough and subjected to this test.

I also stated that a lower frequency AM (Amplitude Modulated) signal can sometimes expose weaknesses with a given product design that a transient test will expose.


As to the FCC (Federal Communications Commission) OET (Office of Engineering and Technology) EA (Equipment Authorization) reference, if you look on the back of any unlicensed device which intentionally generates RF (Radio Frequency) emissions, you should find a manufactuer and product code identifier. With that identifier, you can look up information regarding that specific device, on the FCC's website, as that information becomes part of a public file. The direct link to this information was provided earlier in this rather lengthly thread, so I didn't see the need to re-post it.

I think it is unfair to IFI that we publicly speculate as to what the root cause of this problem is, or is not, without factual information in hand. However, as someone experienced with product design, including RF design, I will state that I do not believe that "cell phones" are the problem here. As I indicated in my response, our build location is not located near any RF sources (i.e. transmitters), let alone any that would be synchronized in time with the actuation of the motors.

Ultimately, whatever the cause of the problem affecting a few of us may be, the responsibility to resolve it lies upon the manufactuer and or FIRST to work out a solution. Those among us, such as Eric, with equipment to perform testing that IFI may not otherwise be able to accomplish on their own, may be able to provide some additional data to IFI that would help them.

I hope that helps,

[mtaman02]

How about a machine shop, given the number of different types of equipment and such in a machine shop, would any of that equipment be enough to disrupt RC to OI communictaions for a few seconds? Same goes for a wood shop?

[esquared]

Eric,

Pictures of the radio's internals are part of IFI's FCC OET, EA public file as is the emissions test report performed on a prototype unit.

Based on my own observations of the problem, an Electrical Fast Transients test, such as EN 61000-4-4, might be more revealing than an RF succeptability test, but certainly a lower frequency, 100% AM modulated signal can reveal problems that an EFT test would also expose.

Again, without motors running, we saw no indication of packet loss.

Our build location is surburban with no close field radiators, let alone any dynamic radio transmission that would be tightly coupled to motor actuations.

The comment about cracking the box was in regard to seeing if the automatic gain control (assuming the IFI RF frontend was using this) was kicking in to some unknown response. With a few oscilloscope leads we could check to see if this was occurring.

We performed no lab testing before shipping the modem back, so other than some more recent comments about potential motor interference the only thing I had to go on was the cell phone comment. It seems unlikely to me as well, but if I'm scanning at 30MHz it's just as easy to let the equipment continue up to 900MHz. Our Biconilog antenna is good to 1Gig, and somewhat shoddy to 3Gig. From 3-9 I've got a log antenna, and past that you'd need a horn which doesn't calibrate well for the 10m FCC testing we typically perform.

I'm pretty limited in the EFT testing I can perform, however we have some loops lying around that might work, albeit in a completely non-calibrated fashion. Certainly anything I try in that realm will be pretty non-scientific.

If IFI chooses to end speculation after a few more radios have been in their lab, that would be fantastic. Like last year's 8.2V problem, there were some intelligent discussions trying to determine what the problem is. The more people with something useful to contribute looking at the problem, the better.

Ninja Edit: Thanks for filling in the details of our acronym-laden conversation Dave. I tried to give some detail to my earlier posts so this doesn't lose meaning to others following the thread.

[Al Skierkiewicz]

E and Dave,
I went to the FCC files and looked over the pictures. Anyone else notice the internal antenna? Is it a dipole with the external antenna or a separate transmit or receive antenna?
I would like to know how many teams having problems have the modem mounted against a metal surface. If any team is having regular problems, could you try holding the modem outside the robot and check for same issues you had when the modem was mounted on the robot?

[esquared]

E and Dave,
I went to the FCC files and looked over the pictures. Anyone else notice the internal antenna? Is it a dipole with the external antenna or a separate transmit or receive antenna?
I would like to know how many teams having problems have the modem mounted against a metal surface. If any team is having regular problems, could you try holding the modem outside the robot and check for same issues you had when the modem was mounted on the robot?

They're definitely separate antennae, one for transmit one for receive. During my discussion with Corey this past weekend, some of his suggestions were to mount the modem vertically, orient the external antenna away from the internal antenna, and to keep it away from any metallic structure nearby that could be acting as a ground plane. At the time, both modems were screwed to pieces of plywood, one for the driver station, and one that was C-clamped to our drivetrain with no structures surrounding it. Implementing those suggestions still resulted in a number of cutouts on Saturday afternoon and Sunday.

IFI should have our modems on Tuesday assuming UPS does its job. Right now, last year's modems are working flawlessly so paying double or triple for to overnight them wasn't worth the cost.

--Eric

[Al Skierkiewicz]

Eric,
Did Corey indicate which antenna was the transmit?

[65_Xero_Huskie]

How about a machine shop, given the number of different types of equipment and such in a machine shop, would any of that equipment be enough to disrupt RC to OI communictaions for a few seconds? Same goes for a wood shop?

I dont think this would be the problem. We work in GM and the WHOLE machineshop is around the corner, we havnt had any problems with the radio as of yet. So maybe it just might be your connections or something other thats simple. Maybe your radio has been brainwashed by another team not to work? :ahh:

[esquared]

Eric,
Did Corey indicate which antenna was the transmit?

Nope. Without knowing more about their link budget, it's not immediately clear which should be which.

Judging from the photos and clever use of MS-paint, the internal antenna is roughly 1/4 wave, and the external roughly 1/2wave for the 902-928MHz band. Assuming no poorly placed metallic structures, and that you aren't purposefully pointing the antennas end-wise at each other, you should get a nice fat pattern off both. Once again, for the interested reader, RFCafe has lots of fun info about antennas, power, patterns, etc. IN particular, check out http://www.rfcafe.com/references/electrical/antenna_patterns.htm

I've got to hand it to the IFI RF guys though, they tuned their transmit strength to be JUST under the FCC limits. Particularly on the RC side :) If there is a signal strength problem, it's not on the transmit side.

I'd say those are my 2 cents, but at this point I'm up to about a buck's worth.

--Eric

[Racer26]

So beyond a relocation of the mounting of our radio, 1075 needs to phone up IFI and ship the radios back? They seem to be much less reliable than the old Ewave models... I'm not sure why we switched either, considering Ewave engineered those radios FOR us. Our old radios were rebranded Ewave Screamer422s for reference, Ewave's website even states that they were specifically designed for us.

[esquared]

So beyond a relocation of the mounting of our radio, 1075 needs to phone up IFI and ship the radios back? They seem to be much less reliable than the old Ewave models... I'm not sure why we switched either, considering Ewave engineered those radios FOR us. Our old radios were rebranded Ewave Screamer422s for reference, Ewave's website even states that they were specifically designed for us.

If you have the same problems other people in this thread have shown, you've tried mounting them vertically, and not deep inside your robot, then call them up and get an RMA. Since so far there isn't a mass posting of "my radio doesn't work", if you don't have any problems I wouldn't send it back.

[Dave K.]

Nope. Without knowing more about their link budget, it's not immediately clear which should be which.

Judging from the photos and clever use of MS-paint, the internal antenna is roughly 1/4 wave, and the external roughly 1/2wave for the 902-928MHz band. Assuming no poorly placed metallic structures, and that you aren't purposefully pointing the antennas end-wise at each other, you should get a nice fat pattern off both. Once again, for the interested reader, RFCafe has lots of fun info about antennas, power, patterns, etc. IN particular, check out http://www.rfcafe.com/references/electrical/antenna_patterns.htm

I've got to hand it to the IFI RF guys though, they tuned their transmit strength to be JUST under the FCC limits. Particularly on the RC side :) If there is a signal strength problem, it's not on the transmit side.

I'd say those are my 2 cents, but at this point I'm up to about a buck's worth.

--Eric

The parts adjacent to the shield appear as though they might be the first and 2nd IF filters, probably 455kHz and perhaps 10.7MHz or higher, and are only stuffed on one of the boards. So my guess would be that the internal antenna is Tx, and the external is Rx. It seems odd they wouldn't just diplex the external antenna.

As to the Tx power, I was a bit surprised to see that was considered passing and do note a "unc." in the pass/fail column but saw no discussion on it in the report... but certainly that is not a problem for us to consider here as the error is potentially on the side of a tiny bit too much power.

I have my doubts that this is a link budget, antenna tuning, external interference (cell phone or otherwise) issue, but speculation and facts are two different things and IFI is in the best position right now to analyze the facts.

Thanks,

[Dave K.]

If you have the same problems other people in this thread have shown, you've tried mounting them vertically, and not deep inside your robot, then call them up and get an RMA. Since so far there isn't a mass posting of "my radio doesn't work", if you don't have any problems I wouldn't send it back.

Correct, and I'd like to echo that as well, and in part is the reason why I started a new thread, so that we could be very clear that IF you have a problem as some of us have described, that you need to contact IFI and discuss the situation with them, and if they determine that it is necessary, to RMA the unit back to them.

As of Monday this week, only 2 of the 4 teams reporting a problem had sent in their radio's for examination by IFI. I overnighted our teams radios to make that 3 out of 5.

The burden falls upon IFI and FIRST to determine how to address this issue and whether or not it is something they feel warrants additional attention.

As with last years problem, with what I think was a silicon bug in the user processor, that was worked around by a change to the linker file, some people had experienced the problem and others had not. IFI and FIRST were proactive in making sure that by competition time, all teams had been given the information they needed to make the updates, and I think we should be confident that the same level of effort would be applied to this problem, IF (and I must stress IF) this is later determined to be a problem that potentially affects everyone.

The FUD factor (Fear, Uncertainty, and Doubt) might be running a bit high here, but logical thinking will resolve whatever this issue may be, which again has only been reported by a few teams.

Thanks,

[waialua359]

all of IFI's suggestions were tried for our robot. Ex. mounting radio's vertically, away from suggested places, etc. Still the same problem.

Hopefully we will all find out soon the specific(s) on what may be causing these symptoms.:D

[waialua359]

Team 359 UPDATE!!!
We finally tested our new radios from IFI. We tested for two hours with 3 fully charged batteries.
NO. of problems with radio during that time.........NONE!!!!!!!!!!!!!!!

Our conclusion is whatever technical possible reasons it could have been, simply put, the ones that came in our kit was defective, and the new ones that we got work PERFECTLY. Not one time did we lose signal between the OI and the RC.

I hope its as simple as everyone else who have similar problems, to have their radios replaced.

Aloha!:D

[generalsnipe]

i was being really stupid and desided to look at the ifi site for information, and came across the manuel. i might have found the reason for ours not working. cuz when we did it like the manuel said it worked, so might be the error on my part. *slaps self across the head*

[esquared]

The parts adjacent to the shield appear as though they might be the first and 2nd IF filters, probably 455kHz and perhaps 10.7MHz or higher, and are only stuffed on one of the boards. So my guess would be that the internal antenna is Tx, and the external is Rx. It seems odd they wouldn't just diplex the external antenna.

As to the Tx power, I was a bit surprised to see that was considered passing and do note a "unc." in the pass/fail column but saw no discussion on it in the report... but certainly that is not a problem for us to consider here as the error is potentially on the side of a tiny bit too much power.

Thanks,

The Nemko lab I've worked with in Canada has an uncertainty of around 1-2dB for their 10 meter site. It rolls up all the uncertainty in the site, antenna, cables, equipment, etc. Anything less than that uncertainty number means they have to put Unc. in the pass/fail, but it doesn't stop you from passing.

[Swampdude]

Team 179 is also having intermittent loss of connection. It is constant and when it loses signal it takes <10 seconds to come back. It is mounted visibly and away from other components.

[waialua359]

I would send them back. that fixed our problem when we got new ones. seems to me that their must be some defective component when the initial batches were made and sent to teams during kickoff.
Just my guess.:yikes:

[DonRotolo]

i was being really stupid and desided to look at the ifi site for information, and came across the manuel.
I can't find the manual, can you post a link to what you found please??

We're seeing some funny stuff, but have NOT actually done any troubleshooting, nor have we confirmed that there actually IS a problem. We'd like to check that everything si correct before jumping to any conclusion.

Don

[generalsnipe]

ysh sure, here it is

[mtaman02]

I went to go help my old H.S. Robotics Team and one of the things I did today was test out the 2007 Robot Control System Package - I hooked it up to a 2003 robot using the default program that was already loaded onto the RC and unfortunately they too have bad radios. At first I thought it was a dead battery dropping the communication so we changed the battery and I kept a very sharp eye on it and when it would lose connection the battery registered +12vdc so we eneded up ruling a battery problem and wiring problem right then and there. Next we moved to a secluded room and still had issues and came to the conclusion that it was the modems. I did contact IFI & left a message with the voicemail but I would like to know is there a specific number you guys called other than the ones on IFI's Tech Support Link? The sooner we can get some new radios the better. The only thing I didn't try was the 2006 modems and I am not up to the challenge of dismantling a robot to get to it.:ahh: One thing I noticed about the Communication Link being lost was that it was happening extremely rapidly no more then 30 secs apart and lasting up to 15 secs without a link. The good part was when the link died so did the robot even though the OI & RC registered as still being connected so thankfully no one was harmed and nothing was damaged.

[billbo911]

Has anyone following this thread tested the new v14 Beta version of the Master Code as mentioned in Team Update #8? It was created to remedy this problem.
I will attempt to test it tonight when I get to the school and post our results.

[paulcd2000]

we've had some similar things, but only for the short term. after disabling the robot goes for about a second, and then stops what's up with that?

[mtaman02]

I was unawair of the upgraded master code I will have to d/l it into the RC tomorrow afternoon but me personally I think it may be a hardware problem more then a software problem.:eek:

[Dave Flowerday]

Has anyone following this thread tested the new v14 Beta version of the Master Code as mentioned in Team Update #8? It was created to remedy this problem.
I believe there are actually 2 problems here, and I suspect the new RC code only addresses one:

1) Dropouts in the communication link between the modems

2) RC continues to run on the last information received for a few seconds when the link drop occurs

My guess is that the new RC firmware addresses the second issue but not the first. We loaded it on Saturday but due to not having a fully-charged battery available and some other issues we're reserving judgment until we do more testing tonight. It definitely did not fix the communication loss, however. We saw the red "No Data/Radio" light on the OI at least a few times a minute, usually lasting about 2-3 seconds.

{edit} Another question that I don't remember seeing: has anyone else noticed quite a bit of latency with the new modems? We were experiencing about 1/2 second delay on any controls from the OI before the RC responded. Tonight I will compare the new and old modems to see if the new modems are responsible for this as well, but I'm curious if others noticed this too.{/edit}

[Jake M]

Hey, guys. Just another team to report the same problem with losing radio connection. We've had it for as long as we've been running, but until Saturday, we haven't been actually driving and operating for an extended period of time. Also, I originally thought it might have to do with how we mounted our RC board. The opposite end of the power distribution rail is mounted close to the RC ports, and you have to apply a decent amount of pulling pressure upwards to plug into them. Originally, I thought this was the problem, but today, I opened up the RC, to check for problems, which I could not find. I also remounted the RC to avoid the pulling, as well as tested the radio cable and tried several different ones. We also tried moving the radio away from the motors and electronics, and positioning it many different ways. Nothing helped, and we still have the problem.

Logically, it seems like it has to be a hardware problem, in either the RC or the radio itself, not a signal interference problem. When the connection loss occurs, I notice several things. Firstly, the radio light on the RC turns red, which normally indicates a lack of any radio at all. And yet, the radio itself still has power. Also, the OI always shows that there is a connection present, despite what the RC light shows. And yes, we also have the continuation of the last command, for a short time.

In addition, I know that we have the master code v13, because I went through each of our RC processors and ensured that the newest version is installed. And yes, we are using all new equipment both on the robot and on the control console.

Does anyone know how many teams have actually reported this problem? I plan to contact IFI tomorrow as well and add our name to the list.

[waialua359]

It seems that more and more teams are having those 2 issues as more teams test.
Once again, we tested at least several different occasions already with our new radios from IFI with NO problems yet.
But also, Unless you have problem #1, how would we be able to fix problem#2?
I agree with team 111, IFI more than likely solved the software issue, but not the hardware issue (problem #1).:D

[Karthik]

I was about to post a question about this also. We are having the same problem! This looks to be a nationwide problem with all teams.

Actually, it's not a nationwide problem. There are a large number (majority) of teams who are not experiencing issues. I'm sure IFI will work to resolve the issue for those affected, as they have time and time again. Normally, I'm one to get into a panic about these types of issues, but not this time. IFI has kept the robots running on the field since the year 2000, I have complete faith that they'll work through this issue. As has been said time and time again, if you are one of the teams affected, contact IFI and they will help you get things resolved.

[Dave Flowerday]

As a follow-up from our testing tonight, here's what we found:

The connection was very unreliable for us, just as others have noted. A multi-second dropout occurs every 15-30 seconds while driving (even when not under heavy load). Does not appear to be a battery issue to me (fully charged battery and backup battery, and voltage on the OI looks good).
The "run on" problem didn't seem apparent, but now the problem is opposite: every time there's packet loss the robot shuts down (triggering single-action solenoids to de-activate, stopping the drive motors, etc). Basically, if the robot doesn't have data, it has two choices: keep doing what it was doing for a bit, or play it safe and shut down. Obvious safety concerns exist with the first (and what was seen in R13 firmware), but serious performance issues exist with the second (as seen in R14).
I confirmed that the new radio modems add significant latency. There's probably 300ms of latency with the new modems. Switching to the old modems eliminated this. I think this will be quite a hindrance to drivers (though I imagine they will mostly adapt and have to predict movements more).
I'll be contacting IFI tomorrow with this information.

[UlTiMaTeP]

Lets make things clear.

Two problems were discussed here today.

1, V13 repeating the last code, for an extra few seconds.
2. Defective Radios


1. With the V14 Beta update this problem should be fixed.
2. It seems that a few of these new radios this year actually have some kind of defect in them.
Lost Packets / No Radio as if it was getting interference or something was blocking the signal. After you have performed all the normal maintenance is when a call should be placed to IFI. The wonderful people at IFI are sending out tested replacements.

[Tytus Gerrish]

I have not yet encountered a radio that will remain functioning for more than a few seconds without cutting out

[Schnabel]

We tested our radio out today, and had a very unreliable connection the entire time. At one point in time, when trying to drive the left side forward, the right side went backward and continued to after disabling.

[whytheheckme]

Our radios have problems too. They cut every 10 seconds or so, and then reconnect.

Jacob

[waialua359]

SOOOOOOOO, if the new beta code supposed to resolve the problems, how come we never downloaded it and our robot/radios work fine now?
The ones that came in our kit was "defective" and by just getting new replacements from IFI, it works fine now after hours of testing.
Seems to me there are more variables in what the problem could be.
Anyways, if it aint broke, why fix it at this point for us.:D

[Alan Anderson]

We tested our radio out today, and had a very unreliable connection the entire time.

On the other hand, I had been using it without incident for a week when working with the camera on last year's drive base, and it behaved itself just fine this evening while I was twiddling with the joystick response. (I was running the OI from one of the old drill batteries for portability tonight. I wonder if that has anything to do with it.)

The only oddness I have noticed with the new radio modems is the time they takes to sync up when first turned on. The old radios found each other within a second or two; the new ones take closer to ten.

[waialua359]

that is TRUE! we noticed that also that it takes a while for them to link up together.
great observation.

[Jake M]

Is this still true for teams who have received new radios from IFI, or who don't have this problem at all?

[esquared]

There is one confirmed response from waialua who had the issues we've all reported, sent his back, got them back from IFI 'repaired', and they now have no issues. There are 2 other teams who I know have sent theirs back (my team, and team 930). Dave K. from 930 will hopefully have his back this week, and update us if his work.

Our radios should be at IFI today, as soon as I hear back from them I will update the thread with what the problem (if any) was. By the time they're back in our hands, our robot will be complete and we'll be able to beat on them for a week or so to find out if they are fixed, and I'll update the thread then as well.

Now that there is v14 out, anyone here who still has their radios AND is currently having a problem, PLEASE post if it helps with either the robot continuing to run after a dropout, or the dropouts themselves. This will help IFI determine if their solution indeed will work across a number of different RC/OI/Radio/robot/motor/etc configurations, as well as other teams!

[Robert Cawthon]

We saw this in one of our test drives. We discovered that our antenna was folded down into the frame of the robot. This shielded the antenna from smooth communication with the controller. It just lost contact for short periods of time and came back. Check to see if your antenna is being blocked by parts of your robot.

[mtaman02]

I talked to IFI yesterday (more importantly an IFI guy that I usually see at my local competition - a good friend) and we went over some "possiblities" such as whats on the robot as far as motors and everything. I explained to him that we were using all of the 2007 stuff on a 2003 robot and he said that I may be tripping some breakers and thats why the OI loses the RC - I told him I doubt it since the robot A) Has not been used / touched in 3 - 4 years B) There was nothing ever wrong with the way it was wired and worked perfectly with all the 2003 gear. We ruled out any kind of interference that may make the 2007 stuff stop talking for brief periods of time. So as it stands to him everything is working fine and the OI - RC radio problem lies inside the robot and whatever modules that are in there to make it move.

He says that if all the Lights on the OI & RC are green at the time of Signal Loss that it is not actually the OI & RC that is losing the signal but a wiring problem that is making it lose the signal possibly all the breakers tripping at once. When I asked about me d/l the beta version aster code 14 he says that it won't solve my problem that its not software related.

I will probably try again with the 2007 stuff on another robot - maybe the 2001 robot since I know for a fact that one has not been touched at all and see if I'm getting the same problems. The 2007 stuff works great on tether just not on the radio. I will also try the 2006 radios if my old coaches let me and see what transpires from that. After I'm done doing that and see what happens I will call IFI again and hopefully someone else will answer and give me a different opinion. BTW the reason I'm not testing on the 2007 robot is b/c it's still getting the finishing touches and is not ready for the control system. Should I wait for the '07 robot to be finished or keep trying it on older robots that I know are Electrically & Pneumatically Sound?

[esquared]

From the IFI FAQ (http://www.ifirobotics.com/forum/viewtopic.php?t=51) be careful when using this year's radios with older robots. Since they just released v14 of the master code with the most recent FIRST bulletin, you may want to use that for any older robot controller tests. It's not clear they've tested v14 with any older RC's, so if there's any trouble try using v13 instead.

Which IFI guy did you talk to?

I wouldn't assume the radios have an issue until you've used this year's controller with them, and the v14 update. IFI is turning our radios around in 1 day, so you've still got time to get them repaired if necessary. Using last year's radios with this year's controller also works perfectly fine.

[mtaman02]

Hrm let me be a little more thorough I used everything in '07 Kit - '07 Radios with the '07 controllers. Nothing was mixed matched unless you meant not to use the '07 Radios and '07 Controllers on a previous year robot.

[Jake M]

Based on what I've seen, I think that it is undoubtedly a hardware problem within the RC or the RC Radio itself (most likely the radio), for two reasons. First, I think we need to assume that the LEDs on the RC are working correctly, because if they're not then there's a hardware problem right there, in the RC. Second, if we assume that what the LEDs tell us is correct, then we know it's a hardware problem somewhere between the RC and the RC Radio, because when the signal loss occurs, the only LED that changes is the Radio State, which becomes red, indicating that there is no radio connected at all. From there, once you make sure that the cable connecting the two is in working condition its easy to understand how the problem has to be within the RC or the Radio Modem. And when you try using older modems and have no problems, you can eliminate the RC.

Anyway, to me the only logical conclusion is that the problem is within the radio itself, especially considering that the teams that have received new radios have had no problems at all.

And my last question was, do the teams who received new radios still notice that it takes several seconds for the radios to initially synchronize?

[roboticsguy1988]

Our team started experiencing problems again. We changed the configuration, per the third post located at IFI's Forums (http://www.ifirobotics.com/forum/viewtopic.php?t=51).

We found that when you make both perpendicular to the floor and away from metal objects they work perfect. But you get a metal object near one of them, or in there line of site they have problems at times. After talking to IFI, they had told us two things to read that post and follow what it said there, and to keep it away form metal objects. Now this seems weird considering most of the field is metal, and the rack in the center is all metal, and other robots are made out of metal. My guess is this year we are going to have problems on the field.

[esquared]

If you've done everything IFI suggested, called them, discussed your symptoms, and your radios are still having problems, they will give you a RMA number to have them repaired.

If you haven't tried their suggestions, or talked to them, and you're having problems...you should try their suggestions and/or talk to them. They're terribly helpful, and once it's clear there is no user error involved, will issue you the RMA.

[waialua359]

Based on what I've seen, I think that it is undoubtedly a hardware problem within the RC or the RC Radio itself (most likely the radio), for two reasons. First, I think we need to assume that the LEDs on the RC are working correctly, because if they're not then there's a hardware problem right there, in the RC. Second, if we assume that what the LEDs tell us is correct, then we know it's a hardware problem somewhere between the RC and the RC Radio, because when the signal loss occurs, the only LED that changes is the Radio State, which becomes red, indicating that there is no radio connected at all. From there, once you make sure that the cable connecting the two is in working condition its easy to understand how the problem has to be within the RC or the Radio Modem. And when you try using older modems and have no problems, you can eliminate the RC.

Anyway, to me the only logical conclusion is that the problem is within the radio itself, especially considering that the teams that have received new radios have had no problems at all.

And my last question was, do the teams who received new radios still notice that it takes several seconds for the radios to initially synchronize?
Based on our tests, yes, but it doesn't really matter since its not really THAT long. Once they connect, they are good to go!

[UlTiMaTeP]

Our team started experiencing problems again. We changed the configuration, per the third post located at IFI's Forums (http://www.ifirobotics.com/forum/viewtopic.php?t=51).

We found that when you make both perpendicular to the floor and away from metal objects they work perfect. But you get a metal object near one of them, or in there line of site they have problems at times. After talking to IFI, they had told us two things to read that post and follow what it said there, and to keep it away form metal objects. Now this seems weird considering most of the field is metal, and the rack in the center is all metal, and other robots are made out of metal....

Obviously you wouldn't want to put your RC radio in the bottom of the robot next to the motors, and you could have some problems, BUT with good visible mounting away electronics and metal, and they still don’t work right, it is a serious problem. This is FIRST and there will be a myriad of metalic objects moving on the field at a time, so chances are, "no metal objects" in its line of sight is obviously not a viable possibility. I have Faith that IFI will have this solved in a week. Go FIRST

[Swampdude]

We got our radios kind of working by getting them at least 8" away from any metal objects. I did tests by blocking the OI radio with an aluminum plate and also positioning the RC radio around in the chassis (w/ and without metal nearby). It looks like if these radios are within 6-8" of aluminum they lose comm (orientation didn't seem to matter). Thats a big problem... We're looking at making a special plastic mount to get this thing up and away from everything else just to ensure a constant signal. The old radios work great no matter where you place them. However they have plastic antennas and these new ones have metal antennas. I wonder if that has anything to do with it. I think FIRST needs to let us use the previous years radios. Theres no way 2000 teams are going to be able to keep their radios in comm and away from aluminum obstructions.

ETA from the IFI Forum (and this IS the fix):
"Poor reception can also be caused from incorrect mounting and wiring. For best radio reception, follows the guidelines: 1) the RC and OI Radio Modems should be mounted high and perpendicular to the playing field. 2) Both the Radio Modem Case and the moveable Antenna should be perpendicular to the playing field. 3) The Radio Modems and DB9 Radio Modem Cables should be kept as far as possible from any High Current Wiring, Motors, and Victors ….etc. 4) The Radio Antennas should not be touching any other surface. 5) The Radio Modem Case and Antennas should not be shielded by any metal structure. 6) There should be a “Clear Line-of Sight” between the RC and OI Radio Modems case and Antenna. 7) Interference from another radio source can be solved by changing to a different practice channel."

But these requirements can be a real pain in the neck depending on your design...

[Al Skierkiewicz]

This brings up some interesting issues with the radios this year. So that everyone knows, the FCC site has internal photos of the radios. These photos show a second antenna withing the black enclosure. It is positioned on the side oppositie the metal antenna. I expect that teams will find more stable communications if this side of the enclosure is positioned away from metal support structure. Only time will tell.

[Samara]

We tested extensively on Saturday and Sunday, both in autonomous and manual drive modes, and continued to experience radio cutouts. After nearly squashing a mentors foot with a speedy autonomous (and un-killable) robot, we reverted to last years radios. I obtained a RMA from IFI on Tuesday afternoon, and our modems ship out Thursday morning.
--Eric
It attacked me too eric =(

[UlTiMaTeP]

ETA from the IFI Forum (and this IS the fix):
"Poor reception can also be caused from incorrect mounting and wiring. For best radio reception, follows the guidelines: 1) the RC and OI Radio Modems should be mounted high and perpendicular to the playing field. 2) Both the Radio Modem Case and the moveable Antenna should be perpendicular to the playing field. 3) The Radio Modems and DB9 Radio Modem Cables should be kept as far as possible from any High Current Wiring, Motors, and Victors ….etc. 4) The Radio Antennas should not be touching any other surface. 5) The Radio Modem Case and Antennas should not be shielded by any metal structure. 6) There should be a “Clear Line-of Sight” between the RC and OI Radio Modems case and Antenna. 7) Interference from another radio source can be solved by changing to a different practice channel."

But these requirements can be a real pain in the neck depending on your design...


While this helps, this in no way solves the problem :( Now it only cuts out every 10 seconds instead of every 5. 2006 Radios ftw

[esquared]

While this helps, this in no way solves the problem :( Now it only cuts out every 10 seconds instead of every 5. 2006 Radios ftw

Call IFI, get an RMA, get them fixed, get them back. This is your last week to do it, and shipping only gets more expensive the longer you wait. They've only had 10 radios to date returned to them, so as it stands right now there is no mass reason not to use the 2007 radios.

Still, I wouldn't want to be at the first regional this year when there are 30 or 40 of these things on at once.

Our team will be getting our radios back from IFI bright and early tomorrow morning, and I'll report whether or not ours work like waialua's do now.

[mtaman02]

They will have 11 when my teams' get there I just sent in my teams yesterday they should be getting them monday! IFI told me to move the modem away from any motors or anything metallic so this is what I did I used a brand new DB9 Cord and put the radio next to the OIs Radio, Put the robot up on wooden chocks and guess what I still had problems and this time the robot wasn't even moving it the signal would just come and go randomly and I said before in prior posts I had this robot in a room where no interference can exsist. It seems like theres more to this story then they care to admit. When you have both the OI & the RC Radios within a foot of one another and neither one of them is near the robot and you still have issues I'd say that thats a defect right there. The 2007 setup worked flawlessly when I had the 2006 Radios hooked up

[RyanN]

Is this a problem that exists with all Radios, or just some? We drove our robot yesterday for about 4 hours straight with no problems with losing communication.

[Al Skierkiewicz]

I used a brand new DB9 Cord and put the radio next to the OIs Radio, Put the robot up on wooden chocks and guess what I still had problems and this time the robot wasn't even moving it the signal would just come and go randomly and I said before in prior posts I had this robot in a room where no interference can exsist.

Mike,
Putting radios close together can be just as much a problem as mounting next to metal or being far away. The high RF levels may just overload the receivers at that close a distance causing distortion in the receiver front end (preamp).

[Japper]

We are having drop out problems with our radio communications too and I thought we had these solved but they came back again....

When we initially had problems with this, our antenna on the robot was within 1 foot away from the drive motors. I then moved it and mounted it on a metal mast which is part of our arm lift mechanism and it was working just fine but now it sems to drop out every 15 seconds or so while driving the robot.

We notice the OI PWM red lights (for the drive motors) are on constant when this happens and sometimes the red No Data/Radio or the No Data lights on the OI light up and stay on for 20 seconds or more while the robot is dead in its tracks. I notice dthat reset clears this and will re-enable the robot.

The green lights on the robot antenna are usually blinking on an off and I have noticed that they do not blink as fast when this condition occurs.

Is this a problem with the RC, the OI, or the antennas?

I am beginning to wonder if this is a susceptibility problem with the antenna unit where we are picking up interference from something else... The location where we are testing the robot has a wireless network, could this be causing some of the problems?

We are also having run-on problems and will load the v14 bin file later today but from what I have read this will probably not fix the drop out problem.

We just wasted a day finding a bind up problem on one of the cim motors and now this is keeping us from the precious time we need...

Any suggestion of how we can over come this problem are greatly appreciated.

Thank you in advance for your advice on the drop out problem.

[vivek16]

hmm no no problems but our antenna did break off...

[Eldarion]

1625 is having radio issues as well. In competition mode, the problem gets even worse. :ahh:

[waialua359]

I am very concerned that as it gets close to the end of build season, many teams will be faced with this problem and the ramifications may be enormous such as not being able to test, waiting for new radios, etc.

[nsr]

yea i don't think we have any problems yet >.<

looking forward to your open house on thursday? ^^

[mtaman02]

I am very concerned that as it gets close to the end of build season, many teams will be faced with this problem and the ramifications may be enormous such as not being able to test, waiting for new radios, etc.

Well as far as not being able to test & waiting for new radios the teams that know this problem already and who have / haven't decided to seek the IFI gods there is still hope for them. One of which is kinda lengthy - Tether the robot (and too be on the careful side if you choose to tether you robot make sure that you do not secure the tether cable competely If the robot should suddenly lose control make sure the tether cable is unscrewed from the OI or the RC side so that the plug comes out w/o destroying the tether port on either unit. Unless of course you put chocks under it then it isn't as lengthy & you can secure the tether cable if you wish.) The other is to use the 2006 Radios which work perfectly with this years OI & RC. Of course these are temporary solutions and will probably need to resolve whatever issues with their radios while the robot has been shipped and hopefully have the newer / re-built radios in time for their 1st. regional.

Like many have said and I will repeat - IF YOU HAVE PROBLEMS WITH YOUR RADIOS TRY PLACING IT AWAY FROM THE METAL CHASSIS & ANY MOTORS, TETHER YOUR ROBOT TO MAKE SURE THAT IT'S ONLY A PROBLEM WITH THE RX/TX ON WIRELESS AND NOT ON A DIRECT CONNECT LEVEL, IF IT'S A PROBLEM WITH THE ROBOT BEING WIRELESS THEN USE THE 2006 RADIO MODEMS, IF PROBLEM IMPROVES WITH THE 2006 RADIO MODEMS THEN CONTACT IFI AND GET A RMA AND SHIP THE 2007 RADIO MODEMS BACK SO THEY CAN REPAIR / REPLACE THEM AS NECESSARY (MAKE SURE YOU ARE VERY THOROUGH WHEN REPORTING THE PROBLEM OTHER WISE THEY WILL FLOW CHART YOU TO DEATH. THE MORE THOROUGH YOU ARE THE LESS QUESTIONS YOU WILL NEED TO ANSWER THE QUICKER YOU CAN OBTAIN AN RMA#. AND AS AL S. HAS SAID MANY TIMES CHECK YOUR WIRING VERY CAREFULLY, WE'RE ALL HUMAN AND MAKE MISTAKES VERY EASILY ESPICIALLY UNDER PRESSURE.

[Japper]

WE were successful at correcting the problem that we were having last night..

Here is what we did:

1). We moved the antenna on the robot so that it is now as high as we could get it and made sure the antenna itself was totally vertical (perpendicular to the track).

2). The antenna unit was mounted to a metal vertical mast on our robot so we attached an "L" bracket to this metal mast and a piece of 1/2" plywood and attached the antenna to the plywood. The antenna is also cable tied to the plywood with a small piece of foam to cushion it and to keep it from touching metal.

3). We re-routed the data cable from the RC unit on the robot to the antenna unit so that is was not near any motors, victors or spikes.

With these three things we did not have one drop out condition all night long...

What a relief it is to clear that problem up... only a few more other problems to figure out.

[mtaman02]

You know what burns me more then anything is that IFI is 1) very doubtful of our problem and that we the programmers and team members are imagining things when the RC system fails for whatever reason, 2) forcing us to build around a problem in which they caused.

Basically this is what they are doing: We IFI have chosen to upgrade the hardware on the Radio Modems to make it bigger and much more harder to mount. You have to mount our radios in such away that it is put in danger of breaking if you don't mount it to our guide lines you will suffer signal degradation. What ever problems you come across are through your own fault and not of ours even though we've tested unsuccessfully the new radios at an offseason event. We will however allow you to send your radios to us for repair / adjustment or replacement if you can correctly identify the problems you are having.

It's bad enough we have to design a robot within 6 weeks to FIRST specs. Now we have to do it to IFI specs to. I don't like this one bit but hey if anyone thinks otherwise then please share your opinion.

BTW got my teams radios back but don't have any time to test them. Much to Much work left to get done. I guess we'll find out come the first regional. :ahh:

[Swampdude]

Just an update from us. We've mounted this thing in the best possible way you could imagine. It's high, its amost 1' away from any metal ( mounted to a plastic panel up in the air. It's vertical and the wires route clearly away from everything that could cause interference. AND WE STILL HAVE DROPOUTS. Not as many but they happen every minute or so, for a second or 2. I'm convinced there's nothing you can do to make these things work properly. They are definitely defective and poorly designed. When I get to our regional the first thing I will do is ask if we can use the 06 radios.

[Mike Betts]

Dan,

First of all, let me say that I respect your opinion and your posts have always had merit. I am going to vent a bit and I apologize for using you as a target but feel it better you than using a student or someone less experienced.

Now to the meat of it:

...When I get to our regional the first thing I will do is ask if we can use the 06 radios.

If you follow that path, you will certainly fail.

Let's assume that the 06 radios work better and that the 07 radios have a systemic problem. If you were running the competition and a number of teams brought the 06 radios and petitioned to have them allowed, would you allow it? Would it be fair to the teams who did not bring 06's? How about the rookies who can not get 06's?

Answer: You could not allow the 06 radios to be used because everyone waited too long to complain!

I looked on the IFI forum today and found only 3 posts about radios not working since the kickoff. Let's assume another 10 teams called on the phone. This is only 13 teams out of 1307 having a problem as far as they know. There are a lot of companies out there which would love a 0.1% return rate.

Your team (and everyone else who is having problems), MUST make this issue clear to both FIRST and to IFI.

$@#$@#$@#$@#$@#ing and moaning on CD will not resolve the problem.

OK. I'm done now and, once again, I'd like to apologize for singling you out. Please forgive me...

Mike

[Dave K.]

Dan,
Let's assume that the 06 radios work better and that the 07 radios have a systemic problem. If you were running the competition and a number of teams brought the 06 radios and petitioned to have them allowed, would you allow it? Would it be fair to the teams who did not bring 06's? How about the rookies who can not get 06's?

Answer: You could not allow the 06 radios to be used because everyone waited too long to complain!

I looked on the IFI forum today and found only 3 posts about radios not working since the kickoff. Let's assume another 10 teams called on the phone. This is only 13 teams out of 1307 having a problem as far as they know. There are a lot of companies out there which would love a 0.1% return rate.

Your team (and everyone else who is having problems), MUST make this issue clear to both FIRST and to IFI.

$@#$@#$@#$@#$@#ing and moaning on CD will not resolve the problem.

Mike

Our team was one of the first to report problems to IFI, reportedly the 5th to contact IFI and the 3rd to return radios for evaluation. IFI gave them a once over, but didn't really find anything wrong.

Testing since their return 2-3 weeks ago, shows an improvment, but not resolution, and I have continued to communicate that message to IFI with hopes that they would be able to provide a solution.

In all other areas, my contact with IFI has been a positive one, and I think that they've responded to my requests in a very reasonable and timely manner, so when it comes to the problem with the radios, I've given them the benefit of the doubt, and for the most part I still do.

Recognizing that we are down to the wire here, and still don't have a viable solution in hand, on Thursday I once again put the question to IFI if they wanted to RMA our existing radios again, or if they wanted to swap them out with others, and also indicated that I felt it was time to elevate this issue to FIRST's attention, and the response was that they'd pass the request up the food chain.

On Thursday afternoon, I sent an e-mail to FIRST's team contact e-mail found here (http://www.usfirst.org/contact.aspx?id=866) and outlined our ongoing problems with the radios and that we were not receiving a solution to this problem from IFI. I ended by suggesting that the regional events make use of 2006 and prior year's radios, and that all non-rookie teams bring old/spare radios to provide to the 2007 rookies.

I have also communicated this same information and request to the regional FIRST contact's to pass along to FIRST as well.

So clearly I concur with the thurst of Mike's input here in that any team that is continuing to experience a radio communication problem, that has already worked with IFI and not yet obtained a satisfactory solution, that it is probably time to make certain that FIRST hears your concerns. Ultimately it is their call as to how to fairly address the problem.

There seem to be many teams reporting success with their radios, so clearly they will have an additional advantage over teams such as ours.

Use the FIRST e-mail address in the link I posted above to make your concerns known. You can also find FIRST regional contact information on this webpage (http://www.usfirst.org/contact.aspx?id=2878).

Please keep your comments and concerns constructive an professional, and please refrain from bashing IFI. The reason for the change in the radios was outside of their control, and while I don't factually know the timetable they had to work with, I suspect it was quite short.

[Doug Leppard]

1902 is having these problems. It wasn't seen until we placed the radios in a real robot, before we tested in a VEX like setup.

We will send an email to IFI also.

[Swampdude]

We DID contact IFI, they kindly directed us to the forum and said that should fix it, have a nice day. In other words we got that same sentiment I'm seeing other people recieved, its not our equipment its how your using it. And that was about 2 weeks ago.

[Doug Leppard]

We DID contact IFI, they kindly directed us to the forum and said that should fix it, have a nice day. In other words we got that same sentiment I'm seeing other people recieved, its not our equipment its how your using it. And that was about 2 weeks ago.

We didn't see the problem until we tested heavily this week. I think a lot of teams are having the problem but just don't see it yet.

Kind of scary thinking your bot can stop at anytime.

[Madison]

(I haven't gone through most of this thread.)

We can confirm that our cellular phones are interfering the radio communication between our OI and RC. It seems to reset or otherwise turn off the OI completely -- our robot stops responding to commands, the LEDs on our OI turn off and things are otherwise completely useless.

Is this a problem with our radios or is this a generic defect with the new IFI radios?

Thanks. :)

[Rich Kressly]

You know what burns me more then anything is that IFI is 1) very doubtful of our problem and that we the programmers and team members are imagining things when the RC system fails for whatever reason, 2) forcing us to build around a problem in which they caused.

Basically this is what they are doing: We IFI have chosen to upgrade the hardware on the Radio Modems to make it bigger and much more harder to mount. You have to mount our radios in such away that it is put in danger of breaking if you don't mount it to our guide lines you will suffer signal degradation. What ever problems you come across are through your own fault and not of ours even though we've tested unsuccessfully the new radios at an offseason event. We will however allow you to send your radios to us for repair / adjustment or replacement if you can correctly identify the problems you are having.

It's bad enough we have to design a robot within 6 weeks to FIRST specs. Now we have to do it to IFI specs to. I don't like this one bit but hey if anyone thinks otherwise then please share your opinion.

BTW got my teams radios back but don't have any time to test them. Much to Much work left to get done. I guess we'll find out come the first regional. :ahh:

While the radio issues are frustrating, please understand one thing. IFI didn't "choose" to upgrade anything. The guts of the old radios are obsolete. In fact, so obsolete that the only thing to do was redesign. It just wasn't possible to create another 1300 sets of the old ones. Why are they so big? That's what it took to try and make the right thing happen. IFI had a significant challenge in making the new radios work. They were testing prototypes as early as July 2006 in competition conditions and were still testing during offseason competition in November 2006.

This is not a situation IFI created, but rather a huge challenge they they have been working like crazy to overcome. The solutions they are providing are the best that currently exist.

[waialua359]

Lets all remember that every team is under different circumstances. Some teams havent reported issues because they didnt have a robot until maybe very recently, enough for them to test.
We were fortunate to have finished a little earlier, thus being the 1st ones to start this thread and report it. Im sure teams are more worried about other bigger things such as building a robot.
For example, we just finally put the diagnostic light on and the solid state relay doesnt work. Then we find out that some teams got the wrong one, which is the case for our team. In addition, we find more info on other threads.
People wont search some threads if there is no problem/challenges to search questions for.:D

By the way, will the competition have spares? We participate the 1st weekend of competitions already!

[bjimster1]

I think we have found a correlation between this and the use of cell phones, especially if you are getting a call or on the phone. Today I got several phone calls while right near the robot as which point RC and OI lost communication. coincidence? I don't think so though, I am not 100%. I'm no engineer or RF expert but thats what I have been able to observe.

[Alan Anderson]

We can confirm that our cellular phones are interfering the radio communication between our OI and RC.
We had an open house today. Students have reported occasional communication glitches over the past few weeks, but when there were a couple dozen spectators gathered around the field, things got very squirrely. After the guests moved away, all was well again. My guess at the time was that it was all the cell phones in people's pockets causing interference.

[waialua359]

so whatever the technical jargon is, these new radios are not as efficiently "strong" as the old ones when other potential interferences occur.

That's so strange. I dont know what it is about our new radios, but we didnt follow anyones advise about where to place them (away from motors, etc.). Our objective was to put it somewhere convenient first. In fact, our's is laying down with the antenna sideways to fit under our ramp platform. We also have a lot of "cell-phones" around including our open house.
Conclusion: NO problems with our new radios.
Must be some non-uniform device inside our radios that vary between teams.

[Gary Dillard]

We DID contact IFI, they kindly directed us to the forum and said that should fix it, have a nice day. In other words we got that same sentiment I'm seeing other people recieved, its not our equipment its how your using it. And that was about 2 weeks ago.

Mike:

I did the same thing as Dan and got the same response from IFI - read the forum and try all the fixes and have a nice day. I even told them that our radios were cutting out in a small closed room sitting on a table a few feet from each other, while we were bench checking the electrical system. No cell phones around, no metal from the robot, direct path between antennas. Never an indication from them that there is a systemic problem. The only reason I called them at all was I saw the hundreds of posts on CD from teams who were having problems, and the advice from one person who had received an RMA number. I did not post my problem here - it looked like it was pretty well covered. I believe your estimate of 10 calls is grossly low.

[Danny Diaz]

We didn't see the problem until we tested heavily this week. I think a lot of teams are having the problem but just don't see it yet.

We just had our "pre-ship mini-meet" here in Central Texas, and we had a number of issues that were very, very strange - I would say they all could be related to the radio modems. It seemed as if when our robot got near our team coach, the robot would be very unreliable. In one event the drivers were pushing the joysticks to make the robot turn, but the robot suddenly became completely nonresponsive, though there was no indication on the LEDs that the radio was out.

Our shop just isn't large enough to do any kind of really decent radio modem tests, though we never had any problems in our shop with the OI and RC between 5 and 10 feet from each other or near our team coach or other sources of interference. This is making us very concerned, we've followed all the regular best practices specified by IFI but there were too many instances of radio unreliability this weekend.

-Danny

[UlTiMaTeP]

I'm so pro-First and pro-IFI its crazy. But, I don't like the fact that IFI is taking the defense that it is our problems, mounting etc. It is obviously a FIRST-wide problem, and a radio design problem. Ignoring the fact that it is a faulty design won't make this go away. Some teams say their new RMA'ed radios have worked better than their first ones.

Our radios lose packets at 3 feet away sitting on top of a wooden table. This year we have a new communications engineer mentor who basicly said, if the connections are tight, and it is still losing sync at that distance, nothing is gonna fix these radios.

As I stated a week ago: IFI will solve these problems, Go First.

[waialua359]

Letting veteran teams use old radios should be allowed in this situation. FIRST is all about sharing and caring. I am sure it wouldnt be unfair for teams that dont have access to them because others would share during the matches.
No one would blatently let a team suffer because of malfunctioning radios.
This would actually help IFI with the demands to fix the new radios.
Even though ours works now, I am still advocating for others.
:]

[N7UJJ]

At our scrimmage in AZ yesterday, there were several incidents of odd radio modem communications loss. Not sure why. It could be because of the radios but then again it can be battery problems, lose wiring, etc.

I think the real problem, for us anyway, is we don't trust the new radios because of all the bad reports. We kind of expect to see radio problems.

I would feel more confident if we were using the older radios. The problem with that, of course, is rookie teams do not have older radios, but veteran teams, who have been issued a radio set every year, have multiple sets and there should be plenty in the FIRST pool to provide everyone at competitions with a pre-2007 radio modem.

Actually, at competitions we only need 6 older radio sets, one for each robot competing. Another dozen or two for the teams in the queue and it seems the radio problem would be solved for this year.

[Doug Leppard]

We had our practice match yesterday, only about 4-5 robots really moving.

There was at least two of us having the radio problems. It goes like this:

1. Radio modem lights flash rapidly back and forth (Standby and Receive)
2. RC lights flashing wierdly.
3. OI lights flashing wierdly.
4. Lasts about 5-15 seconds not enough time to capture what exactly is happening.
5. It seems what ever the robot controller mode it was in stays in. Yesterday it was in fast forward and went into that radio drop out mode and it stayed fast forward and bot climbed the rack to a 45 degree angle. Didn't know it could do that. VERY DANGEROUS, YOU CAN NOT STOP OR CONTROL ROBOT WHEN IT DOES IT.

Does do it more when cell phones are around.

Needs to be fixed or we will have dangerous situations with robots out of control.

[Racer26]

Alot of people are commenting on Cell Phones causing problems with the radios.

I really don't know what they think is gonna happen when they throw 6 robots on the field on flaky wireless connections in a hockey arena full of people with cell phones. Seems like asking for trouble. Our 07 radios seemed to work sort of, but the latency is even an issue. The pre-07 radios were awesome, and I still want to know why we changed. You say they couldn't build another 1300 of them... why not? These are far less reliable, MORE difficult to mount (what was that about equivalent technologies getting SMALLER as time goes on?). I think that the problem is very few teams actually assemble and test their controls in an environment similar to competition, BEFORE the week before ship. THIS is the problem. If this had been construed to IFI they might have been able to fix the situation, or tell FIRST to allow pre-07 radios. I know 1075 has 3 different sets of pre07 radios, and they're all infinitely better than these. We've been testing with 06 radios... supposed to put 07 ones back on it today. Mounting them as good as is possible may still not be enough... there's no way we can mount them 6-8" from any metal.

[Dave Campbell]

We followed the "best practices" from IFI forum for mounting and have the correct version of code, and it still drops occasionally. We'll contact IFI today and make them aware of our difficulties, too. The old radios - which we have 6 pair, work fine!

[Cody Carey]

I still want to know why we changed. You say they couldn't build another 1300 of them... why not?

From what I understand, some of the parts in the old radios were from older cellphones and were obsolete. They had to redesign because they couldn't get a hold of the older parts any longer.


We have Radios from 9 years of competition at our shop... and we would be more than glad to bring them to a competition to lend out to people. I wish FIRST would allow this, because if things continue on as they are with the newer radios... People can expect to be in control of their robot less than half the time during competitions.

[cnat03]

We had our pre-ship scrimmage yesterday and experienced the same issues. I had taken the precaution to download the U14 beta mastercode but it did not seem to solve the problem. We didn't have any issues with run-away robots but we did experience the dropouts and glitchy operation. All of the teams running saw the same issue.

Steve Stark

[triggerhappy336]

Nice to see everyone having this problem, I was worried it was our electronics. Being a rookie team, when the robot cuts motion for not reason, it freaks us out. We had no idea what was wrong.

[Ben Englert]

We are finally system testing (driving + arm + everything else), and we are having the same or similar issues - robot stops moving for about 1/2sec, OI light "No data/radio" flashes, and then everything goes back to normal. Seems to happen with increasing frequency as we slowly add in more and more of our software (presumably putting a higher load on the PIC), which is bizarre because the radio is handled by the master processor, which has nothing to do with us.

[EHaskins]

I was at the Sussex, WI mini-regional today, and everyone there had radio issues.

[Swampdude]

We did cell phone tests tonight. BINGO! Make or recieve a call within 30 feet of the bot and it starts glitching bad (this distance may be greater but I was on the phone and walked away from it and it seemed to get better after I was in the next room). Then also just hold it near the bot (while not in use) and every 15 seconds or so it starts fluttering.
So whats the answer, ban cell phones from the competitions? Can someone get IFI to read this thread? Someone said if it is a cell phone issue, you can't fix it. Which I gather those frequencies can't be altered out of that range? I contacted the FIRST Florida rep (Charles Kennedy), and he's waiting to hear back from FIRST. The way I see it, this is a bigger issue than the banebot problem because we all need to use these radios.

[waialua359]

We did cell phone tests tonight. BINGO! Make or recieve a call within 30 feet of the bot and it starts glitching bad (this distance may be greater but I was on the phone and walked away from it and it seemed to get better after I was in the next room). Then also just hold it near the bot (while not in use) and every 15 seconds or so it starts fluttering.
So whats the answer, ban cell phones from the competitions? Can someone get IFI to read this thread? Someone said if it is a cell phone issue, you can't fix it. Which I gather those frequencies can't be altered out of that range? I contacted the FIRST Florida rep (Charles Kennedy), and he's waiting to hear back from FIRST. The way I see it, this is a bigger issue than the banebot problem because we all need to use these radios.

I bet an update will come out soon saying that old radios will be allowed.:D

[yodameister]

We were doing some testing tonight (finally!) and during the first 5 minutes our driver was driving backward, the bot kicked into high gear and started flying backward. the driver let go of the controls and the bot kept moving. Luckly, we were using a dead man's switch to cut the power and we were able to stop the bot and nobody got hurt (the bot survived as well). the RC antenna was not surrounded by any metal, there was a direct line of sight between the antennas and the distance was about 10' or so. We switched to last years antenna, and everything seems to be ok.

[Dave K.]

From what I understand, some of the parts in the old radios were from older cellphones and were obsolete. They had to redesign because they couldn't get a hold of the older parts any longer.


The RF decks in the eWave designed radios were made by Uniden, and those were no longer available. It is reasonable to conclude that the modules were made for consumer cordless phones, and products of that type. These are channelized, narrow bandwidth, analog FM full duplex transceivers operating as unlicensed devices in the 902-928MHz ISM band.

[Dan Richardson]

We did cell phone tests tonight. BINGO! Make or recieve a call within 30 feet of the bot and it starts glitching bad (this distance may be greater but I was on the phone and walked away from it and it seemed to get better after I was in the next room). Then also just hold it near the bot (while not in use) and every 15 seconds or so it starts fluttering.
So whats the answer, ban cell phones from the competitions? Can someone get IFI to read this thread? Someone said if it is a cell phone issue, you can't fix it. Which I gather those frequencies can't be altered out of that range? I contacted the FIRST Florida rep (Charles Kennedy), and he's waiting to hear back from FIRST. The way I see it, this is a bigger issue than the banebot problem because we all need to use these radios.

Dan, We did the same thing as well today. Everyone in the room 1 by 1 would call their voicemail with their cell phones. We noticed an interesting pattern, while my service ( Sprint ) never seemed to cause the robot to lose radio contact, EVERY SINGLE TIME a cingular or AT&T serviced cell phone was used the robot would immediately lose radio signal. We also found that each time the phone would reconnect with the towers to re-establish signal the robot would break the frequency.

My service is Sprint, and the other sprint phones also never-( or atleast noticeably ever ) tripped the radio. Now the way I understand it Sprint uses a different cellphone technology than both Cingular and At&T. Its this technology that we believe is tripping the radios. We know for a fact that the cell phones would trip the radio, because we tested repeadtly for about 15-25 minutes, turning them off walking away hiding them then calling them or making calls with them.

I don't claim to have any clue whats going on, this is probably apparent due to the vagueness of my post however I do realise there is a problem. During our skrimmage yesterday, there were many times where people came very close to being hurt because of the radio frequency loss, then the robot suddenly coming to life near the sides of the fields. You don't have to be an electrical engineer to realise this is a problem. This type of problem not only can greatly corrupt the competition, it could also cause some significant safety issues, or even potential damage to our robots, I'd hate to see a robot lose radio contact as its driving up a ramp and flip over causings thousands of dollars in damage.

I really hope that IFI will do something soon. I completely agree with you Dan this is a HUGE issue. In the case of the bane bots, if problems occured, at the very worst we could always change companies, or come up with custom solutions. With IFI there is no other option. I know they realise this, and trust they will come up with a solution as they always do. Lets hope it comes before regionals, otherwise get ready to see some of the most interesting/unsightly regionals in years.

[Dave Flowerday]

My service is Sprint, and the other sprint phones also never-( or atleast noticeably ever ) tripped the radio. Now the way I understand it Sprint uses a different cellphone technology than both Cingular and Verizon. Its this technology that we believe is tripping the radios.
Sprint and Verizon actually use the same technology (CDMA). The more important difference is that Sprint's network is entirely in the 1900MHz band, while Verizon primarily uses 800MHz. So, your findings are not surprising. Verizon's phones are using frequencies very close to those used by the radio modems (902-928MHz).

[Dave K.]

I'm so pro-First and pro-IFI its crazy. But, I don't like the fact that IFI is taking the defense that it is our problems, mounting etc. It is obviously a FIRST-wide problem, and a radio design problem. Ignoring the fact that it is a faulty design won't make this go away. Some teams say their new RMA'ed radios have worked better than their first ones.

Our radios lose packets at 3 feet away sitting on top of a wooden table. This year we have a new communications engineer mentor who basicly said, if the connections are tight, and it is still losing sync at that distance, nothing is gonna fix these radios.

As I stated a week ago: IFI will solve these problems, Go First.

To a certain extent, IFI's hands are tied in terms of being able to solve this problem. If they were to modify the design, it would most likely require recertification for the FCC equipment authorization.

I'll again echo my previous statements that in all other respects, my experience with IFI has been timely, professional and reasonable. While I'm sure they can solve the problem, the bigger question is whether they'll be able to do it in both a timely and legal manner.

Based upon what I saw today at the local regional in Sussex, WI, many teams operated successfully, and there appeared to be some interference issues with teams operating on the same channel, however even when the event organizers dutifully checked to make certain everyone was on the correct channel, there were still some teams experiencing problems to the extent that it affected the outcome of the match.

In a couple of instances, I was able to see the lights on the robot's radio showing the radio going into standby and then attempting to find its operator interface again... and this is with less than 10 feet between the OI and the robot.

Instances where more than one radio pair attempted operation on the same channel is quite easy to spot as the Tx/Rx LED's on the radios will be almost constantly illuminated as opposed to the normal alternate flickering. So once you know what to look for, it is pretty easy to see the difference between interference and a radio that has just lost communications with its partner.

One of the teams at todays event simply chose to use the older radios.

While its good to hear that many, and perhaps most, teams are not experiencing an obvious problem, unfortunately our team is not one of those.

Teams experiencing problems, should make all attempts to make your FIRST contacts aware of your individual situations.

At this point, the reasonable and conservative answer would seem to be the use of the old radio's. I'm sure most of us have 18 other design implimentation issues that our time would be better spent on.

[George1902]

EVERY SINGLE TIME a cingular or verizon serviced cell phone was used...
A quick correction to Dan's post: it was the Cingular and AT&T phones causing the repeatable interruption.

My Verizon and and others' Sprint phones caused no interruption as far as we could tell.

[Dan Richardson]

Yes I'm sorry my bad, it was late when I made that post. It was Cingular and AT&T, Verizon and Sprint were seemingly safe.

[Dave K.]

Dan, We did the same thing as well today. Everyone in the room 1 by 1 would call their voicemail with their cell phones. We noticed an interesting pattern, while my service ( Sprint ) never seemed to cause the robot to lose radio contact, EVERY SINGLE TIME a cingular or AT&T serviced cell phone was used the robot would immediately lose radio signal. We also found that each time the phone would reconnect with the towers to re-establish signal the robot would break the frequency.

My service is Sprint, and the other sprint phones also never-( or atleast noticeably ever ) tripped the radio. Now the way I understand it Sprint uses a different cellphone technology than both Cingular and At&T. Its this technology that we believe is tripping the radios. We know for a fact that the cell phones would trip the radio, because we tested repeadtly for about 15-25 minutes, turning them off walking away hiding them then calling them or making calls with them.

I don't claim to have any clue whats going on, this is probably apparent due to the vagueness of my post however I do realise there is a problem. During our skrimmage yesterday, there were many times where people came very close to being hurt because of the radio frequency loss, then the robot suddenly coming to life near the sides of the fields. You don't have to be an electrical engineer to realise this is a problem. This type of problem not only can greatly corrupt the competition, it could also cause some significant safety issues, or even potential damage to our robots, I'd hate to see a robot lose radio contact as its driving up a ramp and flip over causings thousands of dollars in damage.

I really hope that IFI will do something soon. I completely agree with you Dan this is a HUGE issue. In the case of the bane bots, if problems occured, at the very worst we could always change companies, or come up with custom solutions. With IFI there is no other option. I know they realise this, and trust they will come up with a solution as they always do. Lets hope it comes before regionals, otherwise get ready to see some of the most interesting/unsightly regionals in years.

For those interested in some additional background...

Both the old (eWave) and new (IFI) radios use unlicensed (Part 15) frequencies in the 902-928MHz band. Both radio designs use relatively narrow channels, as opposed to a spread spectrum design. Both designs operate full duplex, with the OI and RC radios transmitting near either end of the spectrum.

"Cellular" carriers use spectrum allocations in the 824-849MHz and 869-894MHz, with the subscriber units transmitting in the lower channel block.

"PCS" carriers use spectrum allocations in the 1.8-2GHz range.

Cingular/AT&T uses GSM (Groupe Special Mobile) as the air access standard for their subscribers. GSM is a TDMA (Time Division Multiple Access) standard which assigns each subscriber a fairly precise time slot in which your device transmits a burst of data, representing compressed voice and control information. The packet frames are sent at a relatively low repitition rate of 217Hz or one of its submultiples.

That 217Hz packet rate results in a rapid on/off keying of the transmitter in the phone. The resulting modulation is AM (amplitude modulation) which can be problematic for many devices, whether they are radios or not. The succeptability some devices have is that components like diodes and transistors make good receivers because they will rectify the incoming signal, and by extension components like operational amplifiers (op-amps) that have transistor inputs are among the most succeptible for near field signals.

CDMA (Code division multiple access) is a spread spectrum technology that assigns each subscriber a PN (Pseudorandom Number) sequence with which to scramble their transmissions. The transmitter technically remains on the air while the frequency that it operates on is rapidly changed in a psueudorandmon manner. Phones that use this technology will typically not impact succeptible devices as much as a device using a TDMA/GSM type of modulation scheme.

Cingular and AT&T Wireless, pre-merger, both held "Cellular" and "PCS" licenses across the country, the local use of which was determined by how they came to own the licenses in a given market. Both companies heritage, in some markets, trace back to the wireline LEC (local exchange carrier) license grants in the early 80's where the LEC was given one 'cellular' channel block, and a wireless carrier was given the other 'celluarl' channel block.

Starting in the 90's, the newer 'PCS' spectrum was auctioned to new carriers, and companies such as Sprint got into the cell phone market, and established cellular carriers also bought spectrum in other markets.

Sprint uses PCS channels for their national system, and is CDMA.

Verizon Wireless came out of the merger's of Bell Atlantic Mobile Services (BAMS), GTE and Vodaphone, and the combined holdings and subequent acquistions and expansions have all utilized CDMA technology as their digital air access standard. In markets where Verizon's heritage is traceable back to the origional LEC, largely in the east, they primarily operate on celluar channels, though many areas both celluar and PCS are used for capacity. Local to me, Verizon uses PCS channels obtained through their acquistion of PrimeCo wireless which had constructed systems in the midwest, and if I remember correctly also had a prescense in Florida.


If celluar phones utilizing GSM/TDMA technology are found to drive the IFI radios nuts, then I suspect that Nextel subscriber units would also have the same potential for problems.

Nextel is neither a cellular nor PCS carrier, they are a SMR (Specialized Mobile Radio) licensee that has a patchwork of 800MHz spectrum holdings in which they have constructed a cellularized, full duplex, two-way radio network. Nextel uses a Motorola propriatary TDMA technology marketed as iDEN (integrated Digital Enhanced Network). iDEN's packet rate results in the subscriber devices transmitter typically being modulated at 22Hz.



In our teams situation, I've not attempted to torture the radio's with any cellphones, nor has anyone been on their phone's nor has any phone alerted (i.e. rang) during our tests. In many cases, I've been the only one present, and my phone is Verizon CDMA using PCS channels.

I'm not saying that there isn't a problem with susseptability from cellphones, just that in our case, I believe we are being affected by a different problem, as our packet loss events appear to always be tied to large demands on our electrical system.

[Dave K.]

We did cell phone tests tonight. BINGO! Make or recieve a call within 30 feet of the bot and it starts glitching bad (this distance may be greater but I was on the phone and walked away from it and it seemed to get better after I was in the next room). Then also just hold it near the bot (while not in use) and every 15 seconds or so it starts fluttering.
So whats the answer, ban cell phones from the competitions? Can someone get IFI to read this thread? Someone said if it is a cell phone issue, you can't fix it. Which I gather those frequencies can't be altered out of that range? I contacted the FIRST Florida rep (Charles Kennedy), and he's waiting to hear back from FIRST. The way I see it, this is a bigger issue than the banebot problem because we all need to use these radios.

This evening I implimented code to watch for packet loss, for more information see the details and example code in this thread (http://www.chiefdelphi.com/forums/showthread.php?t=54279).

With a packet loss counter displayed on the operator interface, I had a couple of Cingular (i.e. GSM) phone users setup calls within proximity to the 2007 radios, and boy did the packet loss counter take off. This was not a difficult problem to reproduce at all, nor did the phones appear to need to be particularly close to the radios. We didn't do range testing to see how far away they would still cause problems.

With eWave radios, the problem could still be produced, but the phones had to be within about 12-18" before some minor packet loss was noted.


My CDMA phone affected neither.


I also tested with a /\/\otorola 450MHz 5W handheld and found that it was fairly difficult to disturb the 2007 radios, but when I did, they took quite a while to recover, and it seemed to be longer than it normally takes for the radios to sync in the first place.

When I tried the same test with the eWave radios, I found that they were actually more succeptable to interference from the commercial handheld radio than the 2007 radios were. However, the eWave radios never experienced anything more than a few packets being lost when the commercial radio was keyed, whereas the 2007 radios lost sync for up to 20 seconds as a result of a single transmission on the commercial handheld.


With regard to the V14a firmware, my test code seemed to indicate that the robot controller will disable the outputs when 8 consecutive packets are lost. My number could be off a bit, as I sometimes saw as many as 12 missing packets prior to the RC disabling the outputs, but its right in that area somewhere. In otherwords the outputs will be disabled 200-300ms after packet loss starts to occur.


With the packet loss counter displayed on the operator interface, over several minutes of operation, both the eWave and IFI radios showed occaional packet loss counts during the regular course of operation, however the packet loss rate was higher for the IFI radio than the eWave radio. I won't quote specific numbers nor quantify that statement as I wasn't making a specific expermient to instrument packet loss.

The environment that I was testing had no other 900MHz signals present, as verified with a spectrum analyzer.

Overall, the IFI radio design appears to be quite a bit more succeptable to cellular phone interference than the eWave design, however the eWave design was more succeptible to 450MHz two-way transmission.




From a design curiosity standpoint...

Additional testing shows that the IFI designed radios are FSK radios using channels spaced 150kHz apart. The RC radio channel 1 starts at 902.100MHz and works up from there. The OI radio channel assignments are less obvious, and not sequential, operating in the 922-928MHz portion of the band.

The eWave designs operate on 50kHz channels with the RC side transmitting on the lower frequency channels, just like the IFI design, and appear to be AFSK. Presumably the AFSK approach avoids needing to design the transmitter/receiver to be able to essentially pass/recover data down to DC. The latter results in a slightly more complicated synthesizer design because the PLL reference needs to be modulated in addition to modulating the VCO.

The IFI FSK signal appears to contain a ~3ms pre-amble prior to the data, which I presume is to center the recievers data-slicer, then sends the data, and then sends what appears to be a post-amble. Given that the data is true FSK, its not clear why a post-able burst could be helpful.

I also noted that the signals didn't appear to be properly pre-emphasised, so the higher frequency content of the signal didn't deviate as widely as the lower frequency data, nor was the signal necessarily well balanced. Depending upon the data-slicer design, this could certainly result in a reduction of performance.

While a bit hard to tell, the signal encoding didn't appear to particullarly try and place a limit on long strings of 1's or 0's as long periods of mark and space were evident, which again can make the design of the data slicer a bit more challenging.

Again, this last bit is offered just as insight into the radio's design. I have no reason to believe that the modulation methodology plays into the performance problems that I've noted, and believe are tied to power supply issues, nor should they play a great part in the receivers succeptablility to GSM/TDMA type transmissions... that is unless the succeptability problems are related to RF getting into post receiver circuitry.

[Al Skierkiewicz]

However, the eWave radios never experienced anything more than a few packets being lost when the commercial radio was keyed, whereas the 2007 radios lost sync for up to 20 seconds as a result of a single transmission on the commercial handheld.


Makes you want to think that the AGC delay release is set a little too long doesn't it.

[Bharat Nain]

So is playing with broken radios this year a part of the game challenge?
..

[benhulett]

They should tell everyone with Sprint & AT&T service to shut off their cell phones :D

[Mike Betts]

They should tell everyone with Sprint & AT&T service to shut off their cell phones :D

Ben,

People don't turn off their phones in restaurants, movies theaters, meetings or Broadway shows. They text message while driving down the interstate. They even ignore FAA regs and jeopardize their very lives by using phones while taking off on commercial jets.

What chance do you think you have in getting people to turn off their phones at a robot competition?

JMHO.

Mike

[mormannoob]

our radio channels are different RC is 32 and OI is 40 anyway to fix and i'll try it at regionals

[Cody Carey]

So is playing with broken radios this year a part of the game challenge?
..

I would certainly hope not...

[nuggetsyl]

I wonder if first will let you use last years oi and rc if yours does not work????

[Dave K.]

our radio channels are different RC is 32 and OI is 40 anyway to fix and i'll try it at regionals

It doesn't work the way you are describing it.

The radio 'channel' involves a pair of channels between the OI and RC.

The channel pair is determined from the OI side via the dip switches OR via the competition connector. The OI radio begins transmitting on the selected channel, and the RC radio scans all available channels until it finds an active transmission that contains your team number.

The initial tethering process after setting your team number on the OI is how the RC comes to know which 'team' it is associated with.

Set your team number, tether the OI and RC, remove the tether and you should be good to go.

[Madison]

For what it's worth -- we just received an e-mail from the Pacific Northwest Regional Director asking that veteran teams bring along 2006 radio sets to act as backups, should they be needed.

[ChrisH]

For what it's worth -- we just received an e-mail from the Pacific Northwest Regional Director asking that veteran teams bring along 2006 radio sets to act as backups, should they be needed.

The Regional Committee Chairman for the Los Angele Regional will be doing the same if she hasn't already. Team 330 alone has six working units of the old radios. If all of the veterans in our area bring their radios as well we should be well covered.

Just a reminder... bringing old radios is a cheap, low impact fall back solution. We will at least start with the new radios.

ChrisH

[Bharat Nain]

If there are too many problems, a decision will have to be made on whether FIRST should use the new radios or old radios for a particular regional. I say this because you cannot just keep switching radios on robots and player station randomly. It will create too much confusion and maybe unnecessary work. It will also waste a lot of time.

Luckily, we sent ours to IFI and they told us that there was a bad board in it. They also confirmed that it is now repaired and it will work flawlessly at the regional. I hope everyone else having problems connected with IFI(and something was done about it).

[heydowns]

All teams should closely examine team update #15 for vital radio information:

http://www2.usfirst.org/2007comp/Updates/2007%20Team%20Update%2015.pdf

[Mark1153]

No radio trouble for us at BAE Regional.
We had a ton of trouble with our radios at a pre-season mini-meet and during our own testing sessions. When Cingular cell phones rang within about 30' we lost communications. The radios also broke up at other times, not sure why.
** But with the v15 RC update, and the update done by IFI to our RC Radio [and everyone elses] at the event, we had absolutely no radio problems. I just wanted to say thanks to IFI for working the problem and getting it solved.

[whytheheckme]

No radio trouble for us at BAE Regional.
We had a ton of trouble with our radios at a pre-season mini-meet and during our own testing sessions. When Cingular cell phones rang within about 30' we lost communications. The radios also broke up at other times, not sure why.
** But with the v15 RC update, and the update done by IFI to our RC Radio [and everyone elses] at the event, we had absolutely no radio problems. I just wanted to say thanks to IFI for working the problem and getting it solved.

Ditto. Also, Cingular cell phones wiped all the room key cards at our hotel...

Jacob

[mtaman02]

The IFI guy at the NJ Regional (Rick) had each team informed to bring their radios to a secluded room at the arena and he would flash the RC Radios with new software. The process took all of about 5 minutes to complete. While the update made the radios work a bit more better, it also made the location of the radios in teams robots seem more of the problem and a few teams had to re-locate the radios so there were no more problems with data packet loss. All in all once all the RC Radios were upgraded and the RC's upgraded to v15 there were little to no problems with the robots working on the field. You still had interference while working off the tether and no interference on the tether but thats to be expected while working in a room down the hall, at a practice field or in the pits.

[Alan Anderson]

...You still had interference while working off the tether and no interference on the tether but thats to be expected while working in a room down the hall, at a practice field or in the pits.

Actually, at competition it's expected that you never run the robot without the tether unless you're on the field. If you used your own OI radio, you were interference.

[Bharat Nain]

IFI did a great job coming up with the fix(es) for the radios. At NJ, I did not notice any radio problems - which is better than even previous years. Nice. I love it when there are less unnecessary problems to worry about.

[Al Skierkiewicz]

Actually, at competition it's expected that you never run the robot without the tether unless you're on the field. If you used your own OI radio, you were interference.

Just so you all know, the IFI people use a monitor device that shows your team number and a variety of stats on your robot when you are using the radios, even in the pits. Use your tether at all times you are not on the field or you may invite a visit from a friendly inspector or IFI rep.

[Gary Dillard]

The IFI guy at the NJ Regional (Rick) had each team informed to bring their radios to a secluded room at the arena and he would flash the RC Radios with new software. The process took all of about 5 minutes to complete. While the update made the radios work a bit more better, it also made the location of the radios in teams robots seem more of the problem and a few teams had to re-locate the radios so there were no more problems with data packet loss. All in all once all the RC Radios were upgraded and the RC's upgraded to v15 there were little to no problems with the robots working on the field. You still had interference while working off the tether and no interference on the tether but thats to be expected while working in a room down the hall, at a practice field or in the pits.

Dumb question from a Mechanical Engineer: by RC radio, do you mean the box with an antenna that is connected to the RC by a cable? Do they need the IO radio as well?

[petek]

Dumb question from a Mechanical Engineer: by RC radio, do you mean the box with an antenna that is connected to the RC by a cable? Do they need the IO radio as well?Yes, IFI is updating the "box with an antenna that is connected to the RC" on the robot, and No, IFI is not doing anything with the teams' OI radios that you would attach to your driver control panel (or wasn't in NJ, anyway).

[mtaman02]

Dumb question from a Mechanical Engineer: by RC radio, do you mean the box with an antenna that is connected to the RC by a cable? Do they need the IO radio as well?

Just the RC Radio needs to be bought to IFI. Teams will be notified when they get to pit admin. at their regional where to bring their radios so that IFI can do the upgrade. Your Radio should only be upgraded once by IFI so if it was done already you may not need to do it again unless it is your first regional.


Actually, at competition it's expected that you never run the robot without the tether unless you're on the field. If you used your own OI radio, you were interference. I was using an example. I'm pretty sure teams know to run their robot on the tether cable when in the pits. But just in case their are a few rookies attending event I would throw that little tid-bit in.