A:AnswerI purchased four and all of mines are on the same channel, however if that channel is being used by someone else becaus all of the frequencies are free, then just rotate to another channel that's clear.
A:AnswerAs I read the instructions that depends on what city you're in. Look I'm in NY and if mines work ok, maybe Tech support is the way to go. Have you tried all of he channels to see what works best? Just a thought