Having changed my main station radio from an IC706 Mk1 to a TS-
850SAT, I have been able to compare the two at LF.

The TS-850 is better than the IC-706 because:
*       It is much more sensitive at LF (even better than the IC-706 plus 
LF pre-amp). It works well down to 30kHz, though not specified.
*       Strong signal handling is better.
*       The AGC can be switched off.
*       More selectivity options (variable bandpass, notch).

The IC-706 is better than the TS-850 because:
*       Frequency readout is down to 1Hz, rather than the 850's 10Hz.
*       Tuning is in 1Hz steps. The 850 is 10Hz, even on so-called 'Fine' 
which does not fine tune, it just reduces the Hz/revolution.
*       Frequency stability is better.
*       Frequency accuracy is better. My old and battered 706 could be set 
accurately to within 1Hz anywhere in its spectrum. I could 
confidently measure frequency with Argo down to 0.1Hz after 
calibrating the radio against 198kHz. By contrast, my 850 has an 
error varying from zero to several Hz from one end of each 500kHz 
'chunk' to the other. 
*       The tuning knob has a finger hole which makes frequency changes 
much easier, both when fine tuning and rapidly changing frequency.

In short, the TS-850 is a better radio, but the synthesiser and its 
tuning knob are poorer than the IC-706.

Hope this helps someone.

73 de Mike, G3XDV
==============