Why you use feeder between BTS to GSM Antennae?

Answer 1

There may be something to this question that we're missing, but here's the

answer to the obvious interpretation:

The BTS equipment is typically housed either in a shelter (building) or else in a

ground-mounted equipment cabinet. On the other hand, in order to achieve

the design area coverage, the GSM antenna is typically on the roof or wall of

a building, on a monopole, or on a tower, located several tens of meters above

the ground level.

The fundamental design of the entire system requires that the transmit RF from

the BTS output be guided to the antenna, and also that the RF received by the

antenna be guided for processing to the BTS receiver, both with as little RF loss

as possible. The "feeder" ... also called 'transmission line' and implemented in

either coaxial cable or waveguide ... is the means to accomplish the transfer of

RF energy in both directions with low loss.