[NLRS] Mirage Preamp Upgrade

[Bill ND0B]

Good morning,

 

Hoping someone can help me out.   Going through Dennis's stuff there are a
lot of preamps of various flavors.   I have been working through testing
them and I ran across a Mirage preamp which was exhibiting 26dB of gain on
432.   That caused me to take notice as prior to that regardless of band I
had been seeing about 14 or do dB out of these beasts.   I noticed a note
that said "upgraded to 1302 FET, excellent results.    THAT had my attention
so I grabbed another 432 MHz Mirage, confirmed it was at 14dB and replaced
the FET with a 1302.   Got 16dB out of it after retuning.    A little more
investigation revealed it was likely a couple more components were replaced.

 

Does anyone have any information on this upgrade?   I have seem a few blips
indicating it can be done but nothing on any other components that need to
be replaced.    I do have the working one and the bias seems a likely place
to start investigating but figured I would ask before I messed around too
much. 

 

I am aware gain is not everything and these should really be tuned for
optimal noise figured, that can come later. 

 

Thank you for any help you can give.  

 

73 de Bill ND0B