View Single Post
  #9   Report Post  
Old October 11th 06, 09:13 PM posted to rec.radio.amateur.homebrew
Harold E. Johnson Harold E. Johnson is offline
external usenet poster
 
First recorded activity by RadioBanter: Aug 2006
Posts: 154
Default effect of cascading LNAs


wrote in message
ps.com...
It seems that I know the Friis equation.

I am asking because it seems difficult, and maybe impossible. I've
never heard of this high gain before, but I dont' know why I cann't
stack amplifiers and I am looking for somebody who can tell me what
exactly the problem is: you see the NF is nice, and I can get the SNR
if the band is narrow enough.

It also seems that I "don't know what I'm doing". So please explain a
little if you want me to understand. Thanks.


Well, how about a little additional information? What is it that you're
trying to accomplish? A gain of 140 dB would amplify a signal of strength 8
x 10^-10 Watts (About the equivalent of a received signal of 10 dB over
"S"-9) to a kiloWatt. I don't think you're trying to do that, so what
convinces you that you NEED 140 dB of gain?

Regards
W4ZCB