[R-390] Spinner knob for R-390

[Miles Anderson]

I answer Randy's question reluctantly for fear that I will draw fire for
maiming a museum piece. But yes, I have successfully done a "slow tuning"
modification for the R-390A. Of course, it involves boring a hole in the
front panel and modifying the front sub panel. I will be happy to post the
shop drawings (if I can find them) if anyone can suggest a site or I will
e-mail them to anyone who contacts me off list.

The modification requires a machine shop or a VERY careful hand with a drill
press, plus disassembling the front panel and the front sub-panel. When
completed, it provides a tuning rate of about 15 to 20 kHz per turn (as best
as I can recall) for CW and SSB. In addition, the "sense" is correct. That
is, you turn clockwise to increase the frequency.

I used one precision anti-backlash gear from Winfred M. Berg Co. that cost
quite a few bucks 20 plus years ago when I did the work. Beyond that, all
you need is a shaft, a couple of bronze bushings, an aluminum plate, three
stand-off posts and a knob.

Miles Anderson, K2CBY
16 Round Pond Ln
Sag Harbor, NY 11963
k2cby at aol.com