In article ,
Tom Horne wrote:

On Monday, December 30, 2013 8:59:38 PM UTC-5, Fred McKenzie wrote:
In article ,

Tom Horne wrote:



We would like to be able to use 50, 144, 220, and 440 MHz radios at any
position and we would prefer not to have to resort to diplexers and separat
e antennas on the roof if it can be avoided.

Tom-



Phil and CRN have good suggestions that directly address your needs.

Another approach for common local frequencies, is to have a single base s
tation for each frequency, with a remote control at each position.

This allows the base station to be located (in a separate equipment room?
) closer to the antenna to minimize feed line loss. All it takes is teleph
one wires to connect between the base stations and remotes. Each remote co
uld have a switch to select base stations.

Fred K4DII

Fred

I take it that would involve using only identical radios so as to be able t
o use any control head with any radio.

Tom-

That may also work with same-family radios on different bands. But
someone with more experience than I, might design a universal remote
that could be adapted to several different model radios.

One approach would be to develop a standard interface consisting of
transmit and receive audio pairs operating at line level, plus a keying
pair. To reduce the number of wire pairs, you could use split-winding
transformers to accomplish DC keying on the transmit audio pair.

Fred