[techhelpbb]

Originally Posted by Tanis

Sure, but you will also remove the possibility of teams having camera feeds back to their driver station, and you will likely have to cut out a lot of the other diagnostics as well, because the bandwidth on those things is pretty low.

If you want to do that, then FIRST doesn't need to police the WiFi band any more and the camera limits go away. So this is probably exactly the opposite of the issue. As long as FIRST allows teams to continue to use WiFi and puts FMS only on the 900Mhz then there is no real issue except a slightly more heavy robot.

In point of fact during the bid round in which the RoboRIO was accepted I proposed in writing to FIRST this exact solution.

You also have to start dealing with the limited range and the connection dropping when certain objects come between your DS and your robot again.

That's interesting. Why would 900MHz have a harder time with objects than 2.4GHz or 5GHz? It should be the opposite unless you turn down the 900MHz transmit power substantially. In 1996 we used 900MHz serial for the robot control to the Parallax BASIC Stamp 2 control system with large metal field pieces and I saw no evidence of this issue.

As for the DLinks from previous seasons- one of the major reasons they were dropped was that they were the biggest culprit in the "christmas trees" that we saw in the past. This is when all robots on the field would start moving jerkily or dropping out completely. The DLinks didn't quite conform to the WiFi standards, in a way that almost guaranteed christmas trees in poor connectivity situations.

The D-Links were FCC certified and confirm to the necessary transmit and receive standards. They didn't fully support QoS correctly and therefore the harder the field tried to rate shape them the harder they'd try to send. They only made it worse with some crazy boot behavior and TCP/IP oddities.

Then again if we simply stop allowing power to the radios to be disconnected we'd not have to worry about these crazy boot issues except when loading the field. I really think FIRST should find a way to support batteries for those radios as others have mentioned, but finding a wide enough selection of COTS radios with this feature is going to be tough. I doubt FIRST wants to make custom mobile robot radios as I have mentioned it to them before.

Picking a radio for FRC is not an easy task, and it is often a game of tradeoffs. Knowing the team at FRC working on it, I think they understand the tradeoffs and requirements very well and will make a good choice.

On this we agree these stationary bi-directional transmitters were not meant for mobile robot applications. It's literally a game of compromises till someone decides to make a mobile robot radio in the price range. Frankly the compromises do not actually bother me - the lack of warning about those compromises does bother me. I really do think you can't test for all the problems you will find in use with the sample set you will likely have before you buy. Therefore I am neither surprised nor all that frustrated by Kate's announcement. These radios are cheap compared to the cost of sitting dead on a field. I am actually happy that FIRST has realized the importance to the degree that they are prepared to try to do better continuously even if this is inconvenient.