Thanks so much for the photograph - HF-281, quite rare item.
It is my 2nd chance to see it… I understand that it was designed
for the commercial use and comes with the mechanical filter in
in place of HF-380’s PBT unit.
I see that you added some modification in order to provide the
General coverage operation by 100Hz step, upgraded from the
original HF-281 which comes with fixed 6-channels only.
Above all… I do remember that the HF-281 generates an outstanding
and beautiful SSB modulation. One of my local HAMs always worked
on HF-281 & HF-282, ‘cause of its Hi-Fi SSB audio..
If you have a time, I appreciate your contributing more photographs.
Take care, Best of Luck – 73 !
Sean JF1QBV (Tokyo, Japan)