[R-390] OT: Other Radios You Like

[2002tii]

I strongly agree with the SP-600 recommendation.  If you have a 390 
or 390A, the Collins A and J series don't really bring anything new 
to the party -- you have the best one of the breed already.  If you 
want another Collins design, the S series may be worth considering, 
although some may not consider them to be true boatanchors and their 
AM filter is a bit narrow for strong-signal MW and SW broadcast 
use.  They are exceptional for SSB and CW, however.

The SP-600 is quite different from the Collins designs, and a very 
interesting design in its own right.  There are a couple of known 
issues:  Some versions have IF output amplifiers that run the tube 
into severe nonlinearity, which generates bad spurious responses at 
910 kHz and other harmonics of 455 kHz.  This is quite easy to 
fix.  (Put a scope on the 455 IF output -- if it is a nice sine wave, 
it doesn't need fixing.  If it is distorted, I can post a good 
fix.)  They also need their paper caps replaced.  Use 0.1 uF 
ceramics, like the Hammarlund engineering change called for, and keep 
the leads short.  Don't forget the caps in the RF amplifier and the 
tuning turret.  Much as I like Orange Drops, SP-600s that are 
upgraded to ceramics have better spurious response performance than 
ones where the caps were replaced with ODs.  Once these issues are 
taken care of, the SP-600 is a truly wonderful radio.

Other possible candidates are the National HRO-60 (a quirky choice, 
not great for SSB, and you need the plug-in coils); Racal RA17/71 or 
RA117/6117 (all scarce in the US); Hallicrafters SX-88 (very rare -- 
one just went for nearly $5000 -- I've never seen one, so I have no 
idea how good they are, but I very much doubt $5000 worth!); RCA 
AR-88 (not very good for SSB, and not as sophisticated as some 
competitors, but very fun to operate, over 100 lbs, and looks like a 
million bucks); Rohde & Schwarz EK-07 (beautifully constructed, but 
performs no better than an SP-600, R390, or R-390A); Siemens E-311A 
(very interesting design, somewhat quirky operation); TMC 
GPR-90/91/92 (very nice radios, but not as nice as the SP-600).

Best regards,

Don