[MRCA] WTB BC-459-A *Update*

[Jonathan Jesse]

Thank you Jeep and Robert WA5CAB for all the good info.  All of these 
emails have been saved to a folder.
I did open the cover today to see how it looked inside and to get the 
xtal freqs for Mike KK5F.
looking from the top down the insides look "clean".  Everything appears 
to be intact.  No dangling wires/connections and no open spots.  All 
tubes are accounted for.  It looks like it was removed from service and 
stored.

There is an interlock.  The only stenciling on the right is M5 in yellow 
over M6 in orange/red.  I don't know exactly where to look for the 
Collins logo.
I've been looking at tons of PS schematics so now the parts hunt is on.  
Shouldn't be too hard to find a BC-348 either.

I pulled the tuning chart off.  It's an index card (lines on the back) 
that's laid out with a grid, labeled and tuning instructions that 
mimeographed.  The freqs were then typed in.  There was second card 
under the first. Original.    The freqs are handwritten in pencil.  
Across the top are spots to write in the radio serial number, aircraft, 
and position.  Unfortunately they're blank.
The spring loaded backing plate has EASTERN STA printed on the rear.

Thanks again,
Jon
WS1K

On 10/19/2015 9:24 AM, DSP3 wrote:
> Jon,
>
> A nice find, indeed.  Couple of points to reinforce other comments 
> you've received.  The observation that "hacked" connectors are 
> attached is a good sign.  Truth told, unless someone has tried to add 
> 10 meters, or the like, the chances are that your unit is stock.  That 
> it came from a drone-destined B-29 is a subject for "possible 
> conversation", so to speak.  One does not hack cables and then send 
> the airframe off to fly. You can further check the lineage/age of your 
> unit by looking for a Collins logo on the shelf casting that has the 
> modules attached.  Also, is there an interlock on the transmitter 
> cover?  Are there MWO or TCTO, etc, stencils on the right hand side of 
> the unit, adjacent to the nomenclature tag?  All these are 
> indicators.  You can use any calibration book.  Its just that later 
> versions with the vernier dial can be set more accurately.  To confirm 
> this, look closely at the calibration points and you'll find some will 
> jibe with both book series. The linear PTO is typical Collins.  Of 
> course, the manual has the calibration tables, too.  What you'll need 
> is about 8 amps of 28v DC, 400v at about 270ma and 1000-1300v at about 
> 400ma, peak.  If you don't want the auto-tune to work, the DC 
> requirement will be about 5 amps.  Additional connectors can be had 
> from Wm Perry Co.  Books, good books, come from Robert Downs. Anyway, 
> there is simply not much, if anything, one has to do, internally, to 
> get an ART-13 going.
>
> There are a number of other nuances about the ART-13 that you really 
> should know about.  Those "Necco-wafer" tuning trimmers (a stack of 
> them can be seen on the bottom of the chassis) are very delicate and 
> are often frozen.  If forced, they will crack and replacement is 
> nearly impossible.  The Comco addition came about as a stop-gap after 
> an RTCA and CAA symposium in the early 50's.  VFO tuning was not 
> accurate enough and crystal control was the only good way, at the 
> time, to comply.  Hence, the mod kit. The Collins 18S-4, et al, came 
> into service about that time to provide compliant equipment.  Astute 
> observers will notice that the 18S is a re-packaged ART-13, plus 
> receiver!   That said, my ATC came from a NASA aircraft based at 
> Moffet Field.  The date of the tuning chart was 1963! Obviously, the 
> military and Govt had waivers until very late. By the late 60's, AM 
> was almost entirely gone from aeronautical HF.
>
> I currently have two complete ARC-8 setups going here.  Just this 
> weekend I migrated one of them over to ARR-15 receivers (vice the 
> BC-348).  Its pretty amazing how this transmitter, sans modifications, 
> will generally function and fill the bill some 70 years after 
> manufacture.  Try and get your unit going. You will not be 
> disappointed!  .... Also BC-348 receivers, in good condition,are out 
> there.
>
> I, and others, are around to assist.
>
> Jeep - K3HVG
>
>
>

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