Cellphone repeater basics

Outside antennas

How much of an improvement can be expected?

Base station unique ID numerology

CellTracker app for Android

What about “4G” LTE?

Timing Advance in LTE

The short story:

Sector antennas used on cell phone towers are ideal as outside antennas;

The outside antenna should have high gain;

Suitable bi-directional amplifiers are commercially available;

Smartphone apps that provide signal strength and base station ID are useful;

• With the arrival of “Long Term Evolution” (LTE), covering both voice and data frequencies becomes important.

• With the arrival of LTE and 5G, covering several frequency bands used by the carrier becomes important.

Some gripes:

Some providers (e.g. Verizon Wireless), do not encode base station latitude and longitude in their CDMA signal (unlike e.g. U.S. Cellular);

In some regions, some providers (e.g. SPRINT) encode the center of the area that an antenna is designed to cover rather than the actual base station latitude and longitude;

The FCC licenses the spectrum, yet does not provide listings of cell phone base stations and their locations (while such information is available in some other countries).

Some antenna gains may be overstated a bit in manufacturer's listing (common exception: sector antennas);

Berthold K.P. Horn, bkph@ai.mit.edu