[NJARC] Double-Conversion Stewart Warner

[Al Klase]

I'm currently restoring a Stewart Warner "Duo
Super-Heterodyne" Model 105 from the early 1930's.  See
Rider's Volumn III.  Yes, it is double-conversion on the
three short-wave bands.  On the broadcast band, the tube
lineup is 58 tuned RF amp., 58 mixer, 56 osc, 58 177.5KC IF,
27 det, 57 AVC, and PP 47's.  On the shortwave bands, the
normal tuning ganged capacitors are disconnected in favor of
trimmers that tune the broadcast section to 1525KC, and an
additional type 57 mixer and 56 oscillator function as a
tunable converter controlled by a 4th and 5th section of the
main tuning capacitor.  (I've had to move the first IF to
about 1590 to avoid WKBW.  Was the broadcast band limited to
1500KC in those days?)

Can anyone point me to historical info on this set,
production date, magazine articles, etc?  Was this the first
double-conversion radio offered to the public?  Were there
any others in the pre-war era?

Thanks,
Al

-- 
Al Klase - N3FRQ
skywaves@bw.webex.net
Flemington, NJ 08822
Web Page:  http://www.webex.net/~skywaves/home.htm