I know the lossless feedback based on Dr. Norton (Anzac Electronics)
since 1977, when a German M. Martin DJ7VY published in CQ-DL a two
stage preamp for 145/440MHz with BFT66 and BFR34A.
I modified this amp for my thesis on phased array ultrasonic flaw
detectors for lower frequencies. I got much better performance than
with the Plessey SL531. F"=1.9dB, and phaseshift change of less than
1deg. over 102dB dynamic range until +16dBm O/P.
--
ciao Ban
Apricale, Italy

Hi Ban,
Interesting that you mention Anzac, I picked up an Anzac AM-962 at a
hamfest
many years ago, by the looks of it I thought it might be of the
lossless feedback
style, but I never found any confirmation on the net.
Please help me with your terms.

(1) Definition of F"----?

F" is the noise figure. it says how much the noise gets increased in
comparison with a resistor of in this case 50 ohms.


Wow, that's a very low noise figure, do you recall at what frequency
you were working?
How does your amp compare to the amp here?
http://www.kongsfjord.no/dl/Amplifie...And%202N3053%2
0Amplifiers.pdf
Did your design answer any of the questions posed in the article?

(2) phaseshift change of less than 1deg. over 102dB dynamic
range until +16dBm O/P.

let me guess
Very little phaseshift with a large increase of input until the
output equals +16dBm??

yes
When you make a phased array amp this is the most important figure, since
we
want to use zero x-ings to get relevant data. Similar to FM.
This is in general only possible with differential amps, which have at
least
F"= 6 to 8dB. So this application really appreciated this design.
--
ciao Ban
Apricale, Italy