Many thanks to those who responded to my mail on the subject of receivers for LF/QRSS.
and my problems with my 1792.
Paul Hendrik for the URL re circuits Tracey Gardner for the e'bay lead, and Warren for suggestions
re alternative Rx's.
The lack of AGC OFF on DSP receivers is a worrying trend as Andy says.
So I have been looking around!
I have flirted with the possibility of  the Harris 590 or the Collins 2050, both have excellent specs and are non DSP, they look good,but do I want to take on another servicability problem, and they are not cheap.
The Ten Tec RX340 also excellent spec. but its DSP and no AGC off.
The AOR 7030 is non DSP and the spec is good but operationally it is very daunting,and it won't tune in 1Hz steps and it BFO offset has only 33 steps. I am concerned about setting it up for ARGO etc.Any comments Alan? also I guess its coming to the end of its production.
So that leaves SDR receivers like the Perseus, thanks Johan, but these are digital, can the AGC be turned off? and another problem if my computer sound card is tied up  processing  I/Q signals can it  also  do the FFT analysis ? at the same time. Perhaps Andy can help?
So I am still looking
73 Laurie.