Just voted - I voted for all the frequencies, but really I was just voting for 2.4GHz and 40MHz. I forgot about 459MHz because not many people use that but it is viable. Not so keen on 27MHz as there are about six frequencies available for the Futaba Txs and many RC toys using 'splat' frequencies (some channel on the 27MHz band, but which is unknown) so I think interference on that frequency will be occuring a lot more than the others.

I don't think that 40MHz should be written off for this class though. It has worked well enough in the past for every weight class (with exceptions, naturally) and still works well currently. A lot of perfectly good 40MHz units will be getting retired in a matter of months because of the new FW rule so I think this class is a good place for them to be put to good use again. If anyone was building from scratch, I would recommend they get a 2.4GHz unit purely for the signal quality and cost and if I was buying a new unit I would get a 2.4GHz set as well but if I was building a kilobot and had a high-quality Futaba 6-channel programmable transmitter sitting on a shelf gathering dust I would much prefer to use that, especially since I've recently adotped a 'recycle as many old bot parts as you can when building a new machine' approach. I'm also quite partial to my blue Skysport 6 controller; it was my first ever transmitter (and was a pocket-money-saving feat at £120!), been used in every robot competition I've attended, has never let me down and still works perfectly, so I would not want to see it sitting doing nothing or having to put it up for sale because it's taking up space.

Kilobots drivers will also be closer to the arena and the arena is obviously smaller so the chances of having stuttering drive because your robot is miles away at the other side of the arena are going to be a lot less.

What about going with 40MHz to start off with and see how it manages? If it seems that robots are acting in an uncontrollable fashion as a result of the frequency then okay, rule it out but if it is doing a good job then stick with it. I'm not underestimating the power these things will pack - every weight class of combat robotics is inherently dangerous - but with the right safety procedures (links, failsafes etc, which are already in place) using 40MHz should pose no great risk. A quick final point; lots of us already use 2.4GHz and wouldn't want to go back to 40MHz regardless of the weight class so there might not be many kilobots made that would be operating on 40MHz.