Some questions on the legality of Wifi

[peterl]

Originally Posted by jojoguy10

I saw this during CES: http://cassianetworks.myshopify.com/...c51803009fe0b5

It could be a very good solution since it can handle up to 22 devices and a 1000ft radius.

If any teams end up using it, they should post their results here or somewhere. I'm really curious about this product.

I looked into it further, but I am still left with questions. Can you control the smart home devices via their native apps, and if so, does it allow for data transfer to a computer using OBEX FTP? Does it allow for a PAN/LAN like setup so they can access a FTP server on my laptop? I know it isn't released yet, but if someone can point me in the right direction, thanks.

[cbale2000]

As a note to those of you considering Bluetooth, keep in mind that Bluetooth operates in the same 2.4GHz frequency range as traditional WiFi. While potentially harder for field staff to detect (as a WiFi scanner will not see it), if it is detected you will likely be told to stop using it.

I came across an interesting paper that describes, amongst other things, how WiFi and Bluetooth interact with each other: http://www.hp.com/rnd/library/pdf/Wi...oexistance.pdf

[techhelpbb]

Originally Posted by cbale2000

As a note to those of you considering Bluetooth, keep in mind that Bluetooth operates in the same 2.4GHz frequency range as traditional WiFi. While potentially harder for field staff to detect (as a WiFi scanner will not see it), if it is detected you will likely be told to stop using it.

I came across an interesting paper that describes, amongst other things, how WiFi and Bluetooth interact with each other: http://www.hp.com/rnd/library/pdf/Wi...oexistance.pdf

The FRC field is not 2.4GHz it is 5GHz.
Of this I can be pretty sure as I have been a CSA/FTAA.

However feel free to take FIRST's word on it:
http://www.firstinspires.org/sites/d...-frc-qanda.pdf
See Q301.

Keep in mind the field security monitoring tools can still detect the 2.4GHz spectrum but usually we don't police it.

When there were issues in the past with the interference the source that caused the most public examples were all interacting with the 5GHz spectrum. Airport radar can also interfere with the top few channels of that 5GHz spectrum.

Also this 802.11n supports channel bonding which is usually turned on but occasionally has been turned off in the past.
So that means that your robots can use 2 channels of that spectrum to get extra radio bandwidth.
That still does not remove the 7Mb limit imposed between your robot and the field.
That bandwidth restriction is imposed not at the radio level but at the protocol level.

[epylko]

Originally Posted by techhelpbb

When there were issues in the past with the interference the source that caused the most public examples were all interacting with the 5GHz spectrum. Airport radar can also interfere with the top few channels of that 5GHz spectrum.

Those (United States) channels are:

• 52 (5260 MHz)
• 56 (5280 MHz)
• 60 (5300 MHz)
• 64 (5320 MHz)
• 100 (5500 MHz)
• 104 (5520 MHz)
• 108 (5540 MHz)
• 112 (5560 MHz)
• 116 (5580 MHz)
• 120 (5600 MHz)
• 124 (5620 MHz)
• 128 (5640 MHz)
• 132 (5660 MHz)
• 136 (5680 MHz)
• 140 (5700 MHz)

Originally Posted by techhelpbb

Also this 802.11n supports channel bonding which is usually turned on but occasionally has been turned off in the past.
So that means that your robots can use 2 channels of that spectrum to get extra radio bandwidth.
That still does not remove the 7Mb limit imposed between your robot and the field.
That bandwidth restriction is imposed not at the radio level but at the protocol level.

It's something that is set by the access point. You can set your client to be able to use 40Mhz channels but if the AP doesn't have 40Mhz channels enabled, you won't get any benefit.

Finally, 80Mhz channels are possible with the 802.11ac Wave 2 access points which can give you an association speed of almost 3.5Gbps.

[jkoritzinsky]

You guys should take a look at SuperScouter. It allows data transfer over QR codes (and customizable data forms). Take a look at http://jkoritzinsky.github.io/SuperScouter4FRC