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Radio Tech · #11 11-01-2008, 08:38 AM

Quote:

Originally Posted by QRN

I would consider remoting a separate microphone and speaker to control the one radio. At the radio station where I worked we had about a dozen places in the building with microphones and speakers that all connected to a base station located in an equipment rack. Since we had so many speakers we used a distribution amp with 70 volt transformers but the microphones were basically in parallel. For a two or three speaker system you could just parallel them all. That would allow remote monitoring and eliminate the problem of two radios into one antenna.

That is what I would do. One radio with several remote stations. While working in the commercial radio repair field for many years that is how we did it. Very simple. Takes no fancy stuff.

park · #12 11-01-2008, 09:51 AM

Quote:

Originally Posted by QRN

That won't work when both radios are tuned to the same frequency or anything close to that ie VHF channel 16.

Your right, I could not find a same freq duplexer.

Beetle · #13 11-01-2008, 10:21 AM

Don't confuse "duplexer" and "diplexer".

Duplexers for the same frequency, or very close bands of frequencies, are not common. At least these days. Back in the '60s, Navy ships used duplexers to put up to five 1KW transmitters on the same antenna at the same time, with less than half a dB loss on any circuit.

A "diplexer" is what you'd use to have simultaneous 2 meter and 70 cm capability with one antenna. Frequencies are widely spaced, so you don't need a duplexer.

hertz · #14 10-12-2009, 03:33 AM

There is duplexers to use with the same frequencies. Have a look at this for example:
VHF Duplexer - 2 transmitters to 1 antenna

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VHF Radios sharing an antenna