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Re: Topband: HMC580 instead of W7IUV preamp

To: topband <topband@contesting.com>
Subject: Re: Topband: HMC580 instead of W7IUV preamp
From: Mike Waters <mikewate@gmail.com>
Date: Thu, 17 Sep 2015 08:20:10 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Does anyone want to make an educated guess as to how W7IUV's emitter
resistor modification may have affected the NF?

My guess is that the NF was changed little if any. I'm sure it helped the
signal-handling capability.

The only transistor I've ever used in that circuit is a TRW LT1001A. It had
slightly better specs than the 2N5109.

The original schematic is at
www.w0btu.com/W0BTU-broadband-preamps.html and the transformer I used in
the photos was W8JI's idea (in the early 1980s).

73, Mike
www.w0btu.com
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