[Premium-Rx] TELEFUNKEN E1800 & AEG E1800/3 AGC

[Pat1McA at aol.com]

Greetings to All List Members,
 
Apologies but this message is aimed at "the few" members familiar with the  
Telefunken E1800 or later AEG E1800/3 HF Receiver.
 
This receiver is, in my opinion, one of the very finest RF- wise, HF  
receivers ever designed. It tests absolutely flawlessly in all respects  - except 
for the AGC system - which is good on paper and not so  good in practice.
 
I may be completely wrong but it would appear that the AGC system was  
designed as a separate entity by a different, (Logic or  Instrumentation?) 
division of Telefunken.
 
The basic AGC problem is extremely bad control overshoot, especially  
noticeable on FAST AGC. This is due to the unique up/down counting method used  
to insert attenuation or add gain in the IF Amplifier.
 
However there are AGC design variations from early  Telefunken E1800 models 
through to late AEG E1800/3 models.
 
For some reason I feel that the earlier/original E1800 may be better than  
the later ones as far as the AGC control action is concerned.
 
Can anyone confirm this?
 
Following on from my last Winter's work on completely documenting the  
E1800/3 AGC system in detail I am now considering re-designing the  DE1710/2 
AGC/Demodulator entirely. 
 
Has anyone actually done this already?  I would love to hear from  you.
 
Like I always say - "If you do not ask, you do not find  out !"
 
Thanks for your patience...
 
Best regards,
 
Pat G3YFK