Funny - I was searching (again) for a suitable repeater for my 4G hotspot and came upon this forum. I scrolled down and found my own entry from months ago...
Oh well, here's the updated version:
Look guys - I see a LOT of misunderstanding in here, with a few facts scattered in. Lets start with facts:
1) Cell phones/3G/LTE use 700MHz & 1900MHz bands. Sprint/Clear uses 2500MHz.
2) Repeaters dont care what you're repeating - but they have to operate on the RF frequency you're using - 2500MHz in the case of Sprint/Clear.
3) Repeaters are not illegal. On the contrary, they help the carriers by extending their range.
4) Manufacturers are not stupid - repeaters are bi-directional. They include circuits to prevent them from repeating their own signal.
5) You can take a weak signal and boost it enough that the demodulators can work with it. The RF interface of WiMax was designed specifically to handle multipath and does a wonderful job of decoding signal from noise at anything 2 bars and up.
6) You are not "assigned" a tower. That is nonsense. ALL cellular systems include the logic to determine which tower will best serve and automatically establish the connetion to that tower and hand you off to another if you move. That's what "cellular" is all about. Of course, if you're miles away from any tower, you KNOW which one will be best, and you can enhance your signal with a directional antenna aimed at that tower.
7) That JR-30 someone mentionned is perfect, but I haven't found a place to buy one. I just emailed the manufacturer. Of course, I dont know what it costs, but at 1W it is clearly in the "homeowner" class. I'm not yet ready to spend $2600 for a commerical grade repeater.
As an aside, and only because someone mentioned WiFi: WiFi has federally regulated power limits intended to keep the operating range small because it uses shared frequencies. Amplifiing/Repeating a WiFi signal is illegal. That has nothing to do with cellular, which operates on entirely different principles.