[Moon] Preamp on 144 MHz

[Jerry Kleker]

    < HI Peter,

> Had a discussion the other day regarding preamps and noisefigures with a
> friend, thought I'd take it to the expert team on Rainers Moon reflector..
>
> When I started EME on 144 MHz (only 22 years ago) the general concensus 
> was  < I BELIEVE THIS
> that a BF981 with 2dB NF was good enough. Reason given was that the
> background noise was the limiting factor, and a better NF than 2dB was not
> needed.
>
> Anyhow, modern designs that people use today range between 0.2-0.4dB NF,
> and people seem rather determined to reach such numbers. Anything higher 
> is
> dismissed as more or less "non functional".
>
> Now my question to you experts; was the old 2dB NF a myth from ancient 
> times?
>
> If so, what is the actual treshold where a lower system temperature in
> theory (and practice?) has no effect on moon signals? Could it be that all 
> < AND THIS TOO
> the work to achieve virtually zero NF on 144 MHz is just to increase the
> confidence factor for the operator?
>
> On 144 MHz, given good antennas, cables and relais ahead of preamps these 
> IN ADDITION, I ALWAYS HAVE
> days, maybe we are spending too much time worrying about the preamp NF. 
> HAD THE LNA IN THE SHACK, SO
> 
> THAT I CAN CHANGE IT IN 15
> Then again, Lasse SM4IVE is talking about stacking two soundcards, maybe 
> SECONDS.
> that's more important..  :-))
>
> 73 de Peter SM2CEW 
> 73 DE Jerry  W7QX
> www.sm2cew.com
> http://blog.sm2cew.com
>