I'm trying to gain as much understanding as I can about a cell phone repeater kit, in order to install it most effectively. So I thought I'd ask some general questions before deciding to take the plunge.
First, I've heard that for direct communication, the phone and the tower will negotiate for some minimum amount of power which is still useful for the phone. Seems like the tower's goal is to give you maybe -100dbm wherever you are. Does a repeater affect this negotiation? One that I'm looking at says it will default to 65-70db of gain depending on frequency block, and only decrease if it gets oscillation, and a max downlink transmit of -2dbm. But will it attempt to make the signal anywhere near that strong? Or would it just continue to let the phone argue with the tower, acting as the proxy?
Second, from what I understand, the signal strength drops by 20log10(distance). That means at 10 meters from the repeater antenna, you already lost 20db from transmit strength, and 100m away you're now at a 40db loss. Do I understand that correctly? Does FSPL for a directional antenna affect the loss vs distance, or does it just provide an offset to the starting strength? But still, at a friend's house, if I hold my phone against his repeater antenna mounted on the roof just above the dining table, it sees -80dbm. At table level, it's already -100dbm. That's less than 1m!