I'm going back about 33 years, but the Golden Haunches in the town that I grew up in was heard on 35.020MHz FM. I just happen to catch it while doing a FREQ scan with the scanner. It would be dead-air for minutes at a time, then you'd hear a BOING sound, (Like a Mac Computer being booted up.), then a, "Hi!!! Welcome to McDonalds. May I take you order Please?" And, you heard both sides of the conversation. That was with a GND-plane antenna about 30-some feet in a pine tree and this McDonalds was over 3 miles away. However, I was living up on a hill, almost line of sight of the place. I've always wondered about the power of those Drive-In radios, but where I was, even 100mW wouldn't be a total stretch.