does anyone have OI and RC radio issues

[roboticsguy1988]

Our team started experiencing problems again. We changed the configuration, per the third post located at IFI's Forums.

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.

[UlTiMaTeP]

Originally Posted by roboticsguy1988

Our team started experiencing problems again. We changed the configuration, per the third post located at IFI's Forums.

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.

[UlTiMaTeP]

Originally Posted by Swampdude

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]

Originally Posted by UlTiMaTeP

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]

Originally Posted by mtaman02

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.