[amsat-bb] Re: MMIC for LEO preamp?

[Rod Adkins]

I have built a number of DEM pre-amp kits
I am fortunate enough to have the loan of a Noise measuring set - & have
found that the tuning for lowest noise & highest gain are often WAY apart
My input would be - if you have no way to measure noise performance, buy
the ready-built preamp - I have also gone this route, & been very satisfied
(usual disclaimer)

Re MMICs - I have built a large number of these for various freqs &
purpose, using DEM PCBs
Besides the poor NF, these amps are VERY broadband, totally unsuitable for
head-end preamp (IMHO <g>)

Rod Adkins WI6M nr San Diego
17917 Lyons Valley Road
Jamul, CA 91935


> [Original Message]
> From: Curt Nixon <cptcurt at flash.net>
> Cc: <amsat-bb at amsat.org>
> Date: 11/26/2008 7:19:46 AM
> Subject: [amsat-bb]  MMIC for LEO preamp?
>
> SO...now I have made a few contacts on AO-51 and SO-50.  Now I need to 
> get better ears.
>
> I have a very simple mode J setup using a couple of old mobil rigs--the 
> rx unit is an IC 2350H.  10 el cheap yagi through 60ft of LMR400.
>
> I'm considering options for a mast preamp for rx only. I'll be using a 
> diplexer for desense ahead of it, and eventually add coaxial switching 
> so I can use TX.
>
> I'll feed with power through extra wire in rotor cable.
>
> Looking at the Hamtonics, DEMI kit and a hombrew from scratch.
>
> 1.  Any experiences with the DEMI units as kits?
>
> 2.  with there relatively high NF, are the MMIC devices like the ERA 
> series, at all appropriate for simple mast preamps for entry level 
> application?
>
> Thanks to all.
>
> Curt
> KU8L
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