I tried one about 3 years ago. I forget the model, but it was one of best available at that time and expensive.
Don't know if they still work this way, but it kind of stayed in a standby mode watching for a cellular call being placed or being received. Then when it detected a call, it would start relaying an amplified signal. It took a few seconds for that to happen.
That was not a problem making a call. I just waited for the boost. But it was a big problem receiving a call. Most of the time the incoming call would drop due to a weak signal before the booster kicked in.
Afters days talking to their support and trying things, I took it back for a refund. Too bad, because it really could boost a 1 bar signal up to 5 bars. I never did understand why it had a delay on boost. Maybe something to do with the FCC.
