Article below is a part of the assembly process of the UHF duplexer – main article is HERE.
I am very pleased with the results of my homebrew cavity duplexer.
I made 3 RX and 2 TX cavities. Charts below show their specification.
Unfortunately my spectrum analyser is only a nanoVNA and its digital noise is at the level of 75dB, so I can’t measure all cavities connected together, but I can measure then individually and also I can measure impedance and SWR for all of them.
Some extra charts to be uploaded soon!!
As you can see EACH cavity provides 55dB notch attenuation at 9MHz split and only 0.3dB signal loose.
As a test, one day I made a fully copper soldered cavity which provided great 65dB notch attenuation at 9MHz split, which was 10dB greater comparing to the aluminium version. However I would rather not recommend it as it was not serviceable at all, as everything was fully soldered.
The picture below shows a test TX duplexer cavity with a great 67dB notch attenuation. But, unfortunately, as I mentioned before, it was a test only as soldering everything together is quite difficult job. Try yourself and you will see it 🙂 Few more pictures related to this fully copper homebrew cavity duplexer project is here.
