Topband: HMC580 instead of W7IUV preamp

[Mike Waters]

Update: it now looks like increasing the current DOES degrade the NF.

The Motorola LT1001A datasheet (now linked to from my preamp page)
indicates that. I couldn't find a similar datasheet for the 2N5109.

73, Mike
www.w0btu.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).
>
> <http://www.w0btu.com>
>