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Cell Phone Repeater Questions

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hermitengineer:
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!

NiHaoMike:
Any reason to not just use the call over Wifi feature many newer phones have?

hermitengineer:
The place I'm interested in using it has no grid of any kind.  We have a solar system for power, and definitely no internet or wi-fi without the phone.

NiHaoMike:
Try the low tech approach of getting an old satellite dish and putting the phone or mobile hotspot where the LNB goes.

hermitengineer:
The nearest LoS tower is 60km away but also on the other side of a ridge 1km away.  With a tall pole or tree (around 15m), I can peek over the ridge to see the tower.  So it doesn't seem practical to try to use a phone while mounting it to a satellite dish, and I would rather not have to walk to the top of the ridge to do phone stuff.

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