Just promise you'll wait till the middle of the night when it's least busy to fool around. The people that work at McDonalds have enough problems, and don't need any more stress during lunch rush.
Probably 27mhz, 49mhz, or 900mhz, in most cases. They'd have to get a special license for their equipment, otherwise. I'd try a C/B-enabled walkie talkie, and check all the channels.
By the way, intentionally causing radio interference, in this matter, is illegal. The pertinent laws could be enforced by your local PD, or, by agents of the FCC, if McDonalds reports you (especially if they see your car's license plate on their CCTV system, or see your face).
well id longboard there and keep out of sight so no license plates.. besides im only 11 so i cant get my hands on a car.............
Well, as long as he doesn't interfere...
Personally I find the drive through dull as it is, but There is a sort of police scanner- super spy aspect to it. It might be fun to have the knowledge of everybody's order for a particular day.
Sit outside one with a scanner or a portable spectrum analyser and you can find out. Every Mcdonalds probably won't all be on the exact same freq.