Hi - I have been putting some of our ideas into practice, and have
made my first attempt at a H-mode mixer rx. The circuit is at -

http://g4oep.atspace.com/qrss%20rx/qrss_ssb_receiver_with_h_mode_mi.htm

This work is in progress, and I have not fully evaluated it yet, but
the system seems to be working as expected on the bench (no on-air
tests as yet). The diagram is my first draught, and there might be
some errors. Please let me know if there are any queries or obvious
errors.

The adaptation of the h-mode mixer for audio outoput is novel, as is
the rf input configuration. I have reduced the number of transformers
required to just one. I am not aware that any concessions have been
made which might compromise the intercept performance of the system.

The conversion loss is very small. The overall voltage gain from the
antenna to the output of the first opamp is 30, corresponding to an rf
loss of 4db, mostly attributable to the filter. This seems very
promising. The AD797 is a hyper low-noise device.

The lsb rejection is 40-45dB, and the af output abt 1.5kHz.

Andy G4OEP