An Angle Linear is on the list, but out of the budget at the moment.
--- In Repeater-Builder@yahoogroups.com, n...@... wrote:
>
> At 2/4/2009 13:08, you wrote:
> >Hamtronics has a preamp with a helical resonator with a 18dB
preamp. I
> >am at a high elevation with noise all around me. Advanced
R3esearch has
> >a 24dB preamp with a low NF and 1dB compression point. Either
would be
> >behind a WACOM 642 6 cavity duplxer.
> >
> >Which would be the better approach? The ultimate goal is to improve
> >reception of handhelds in a mountainous region.
>
> Neither. I recommend an Angle Linear preamp
(http://www.anglelinear.com)
> with a cavity filter ahead of it. Angle linear has those too, but
you can
> probably find a surplus cavity for much cheaper at a hamfest or
eBay.
>
> Helical resonators are either lossy or don't offer much out-of-band
> rejection. They are really best suited for space-constrained
> installations. Full 1/4 wave or 3/4 wave cavity filters are large
in
> comparison but offer high Q with minimal passband loss.
>
> Bob NO6B
>
