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" <atlant...@...> 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
>
