Re: DMR & GMRS Repeater use of same antenna?
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I've put ham and commercial repeaters on the same antenna before but it's not easy. It takes an extra 6 cavity duplexer that is notch only.. and very careful tuning. I once had two Motorola Quantars,? one on 444.5 and the other on 451.5 using one DB420. The extra duplexer inserted at the antenna feed and each side notched the opposite frequencies, both TX and RX. In fact I have a 2m repeater and a 150 MHz system sharing the same antenna right now using a DB4048 notch VHF duplexer to make them work without interference. Having a UHF ham and a GMRS repeater sharing the same antenna should be easy because the frequency split is a lot greater.? The frequencies involved need to be explored to make sure there's no inter mod mix when both transmitters are on the air and the transmitters need to be extremely clean on their output. Some people will say you need to have circulators in line but I've never had to do that and yes I've checked everything on a spectrum analyzer and everything was clean. Chris WB5ITT? On Fri, May 30, 2025, 6:25?AM Dr. Mikeal Hughes via <N9GI=[email protected]> wrote:
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Chris Boone WB5ITT