Well, I was finally able to rework my 150's band DB4048 duplexer down to 2m. I built some new longer loops as per the info on the RB website, and I fabbed up all new 12.5" RG214 coaxes. Now, the iso (i.e. the notch) is around 81dB, and the insertion loss is around 1.4dB. I think these are within specs.
My question lies in the original layout of the duplexer. Originally, on the side with the 1/4 wave transformers, at the duplexer can there was a TEE, and a shorted stub was connected there. All three on that side had these stubs. The conversion article does not mention using them, although the final picture shows them there. There is no mention of using them, so I removed them. Any idea what they are really for?
