[R-390] New (to me) R-390A Can't Tune SSB

[2002tii]

Jerry wrote:

>Just got a very nice R-390A and the receiver appears very sensitive 
>but I cannot tune in SSB signals. Weak or strong stations are just 
>garbled as if the radio is on the wrong sideband.   *   *   *   The 
>BFO does seem to be functional, at least to my ear,

Tune in a nice, strong local AM station using the 4 or 8 kHz filter 
and carefully center it in the IF, then turn on the BFO.  You should 
get a good, strong heterodyne that varies with the BFO "+/-" knob, 
and somewhere (hopefully at or near the center mark) it should go 
down to a nice, steady zero beat (with no warbling).  If you make it 
this far, the BFO circuitry is basically functional.  Once you're at 
this point, set the knob so it indicates "0" when you are 
zero-beating.  To tune SSB signals, set the BFO to +1 or +2 for LSB, 
and -1 or -2 for USB (when you get a signal tuned, you can make small 
adjustments with the BFO control for best clarity).  I find it 
easiest to tune "down" onto SSB signals -- down the band for LSB, up 
the band for USB.

All that said, the 390 is not really a very good SSB receiver.  The 
BFO injection level is way too low, and the AGC doesn't work 
well.  So you will probably find that you want to turn the AGC off 
and use the manual RF gain control for best clarity.

Others may advocate modifying the 390 for better SSB reception (and I 
have made such recommendations myself), or using an external box on 
the IF output.  But if SSB is the main reason for having a radio, you 
will probably be happier with something different.

Best regards,

Don