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 [email protected] Cc: [email protected] 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 _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb