[Milsurplus] BC-659 vs BC-1335

[Unserviceable but Repairable]

Alan according to W4MEW, the BC620 (20-27 armor / wb FM) & BC659 (27-38
attly) carried a a small 22.5V(?) battery to run the AFC-lock on
transmit.  Well it's presence wasn't well known & when run-down, wud cause
them to jump freq. w/o warning.

The 620/659 used either a dry battery pack or a clamp-on vibrapack (PE120?)
but still relied for bias on the battery inside the xcvr.  All loctal
tubes

The BC-1335 had a self-contained vibrapack & all 7-pin miniatures.
Looks more rugged & was probably just the next evolutionary step.  
It did retain the TX-AFC loop.  Aka a PLL.

In beginning, in '41, Link delivered police FM to armor but their prod'n
limits became clear & Army decided on FM 'round 2 order.'  SCR500 series.

Galvin cudn't make 620/659 PLL run in time for the SCR-500 order & WECo
joined w. Colonial w. BC603/4 rig, which in spite of the shiny buttons, on
reflection is mighty clumsy.  

Big reqm't in those days was xtal control & FM.  Contractors worried
about paying Armstrong for his xtal-controlled phase modulator.  Hence
2 alternate modulation spins on SCR500 competitors.

Then Armstrong relented & sed no license req'd for war neutralizing
issue.

Reason for xtal ctl & buttons?  Fm 1939 Army gave top* priority to ridding
vehicles of radio men.   FM threw in the added qrn quash as a bonus.

Lucky us (USA)

   Marty

* Wisconsin NG unit tried 9M Galvin AM cop sets on maneuver.  FB result save
  for qrn.  Then Ft. Monmouth tried FM.  Don't think Galvin/Moto ever
  forgave Fred Link.