AM radios are very susceptible to noise and not recommended for competition. FM radios are fine but PCM or digital radios offer the best noise immunity. Number of Channels - The biggest decision with radio selection is how many channels. You need at least two, one for each drive wheel. You then need channels for weapons and other controls.
Some people go with two two-channel radios.
This way one person can drive the bot and another person can control the weapons. Frequency Selection - You usually will have a limited selection of frequencies based on what the store has in stock. Make sure you check the TCRobowars web page to see what frequencies are already taken. Two robots cannot use the same frequency. If you get two two-channel radios for your robot, they will have to be on two different channels.