That helical duplexer design is actually the only one I have ever heard of. I think I even contacted the builder once but he said it was too long ago to remember additional details what I can understand.
Even though this particular one sure works, as long as it's the only one around obviously I tend to agree that they must be kind of hard to build or adjust. Anyone else know anything? Especially also about the hybrid ring thing? 73 Martin --- In Repeater-Builder@yahoogroups.com, "skipp025" <skipp...@...> wrote: > > > > > The Helical Duplexer tends to be lossy... it's hard to > get/keep the Q value respectfully high in many home-brew > projects (but it can be done. You might research some > of the older Decibel Low-Band units for examples. There are > actually a fair number of mod/construction projects posted > on the web. > > The 1.5/8" and 1.1/4" (inch) hard line notch pass duplexers > are actually pretty nice... and cheap if you're resourceful > with recycled/removed feed lines. > > s. > > --- In Repeater-Builder@yahoogroups.com, "cruizzer77" <atlantis7@> wrote: > > > > We're going to build a 6m repeater in a place where space is very limited, > > which means that building a full-size cavity duplexer is not an option. > > > > Of course there's the heliax duplexer, but I would also like to evaluate > > other possibilities, i.e. the helical duplexer or even a hybrid ring > > duplexer with helical resonators. > > > > I have got some theoretical info about them, but very few info about actual > > built units. > > > > Has anyone (successfully or not) built a helical or hybrid ring duplexer > > for 6m? Any info appreciated! > > > > 73 > > Martin > > >
