[Milsurplus] BC-938A, BC-616

[WA5CAB at cs.com]

Dave,

So the only difference between BC-938 and C-30/ARC-5 is the nameplate?

Further on Pipsqueek, which is AKA RC-96.  The Contactor Unit (timer box) 
is BC-608-A.  BC-608 was used alone with SCR-522.  And along with BC-616 with 
SCR-274-N.  I think the "channel #4" Dave mentions refers to SCR-522.  I 
don't know which transmitter of SCR-274 was, by default, keyed but presume it 
would have been #1.  As single and two-transmitter installations would 
appear to have been more common than four-transmitter ones.

In a message dated 4/23/2010 12:49:03 PM Central Daylight Time, 
arc5 at ix.netcom.com writes: 
> >Can anyone give some context for the BC-938A control box I found buried 
> in
> >the garage?...
> >As to the BC-616, it is a relay box ...
> 
> The BC-938 is the TX control box for the ancestor of the AN/ARC-5 VHF set,
> the SCR-274N VHF rig produced by W.E.  Only about 1000 were
> produced and most were re-tooled into AN/ARC-5, along with
> a new nomen plate (ARC-5 C-30) for the control box.
> The set looked almost identical to the later, improved ARC-5 that
> saw so much service.  The -274N VHF had an 815 P-P modulator
> built into the transmitter, which was retro-fit out of the AN/ARC-5
> version that went into large-scale production.  That's why early versions
> of the VHF T-23 have a tube socket and two smaller,. plate-cap
> feed-thru holes plugged on the front part of the chassis.
> Some even have "815" marked next to them.
> It is a scarce piece.  I'd trade well for it, if I didn't already have 
> one.
> 
> The BC-616 is part of the "Pip-Squeak" aircraft DFing system the
> Brits used early in fighter direction and which was adopted, though
> I don't think much used, by the Americans.  It used a clock-work
> thing in the inst. panel to key channel #4 for 15 seconds out of each
> minute, so control could DF the aircraft.  The BC-616 provided the
> relay switching to make it happen.
> 

Robert & Susan Downs - Houston
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