[ARC5] Re: A.R.C. Type 7544 ATA Tester

[David Stinson]

WA5CAB at cs.com wrote:
> Correction.  Per list member who "done done it", works OK with AN/ARC-5 
> if appropriate 12-pin connectors and wiring are used.

Mine doesn't work that way.  I never investingated,
but my 274N set would not work properly with AN/ARC-5.
Don't know why.

> ...wonder 
> why A.R.C. used a different connector pair on the late set?
To keep some 90-day wonder "radio man" from plugging in an ATA
screen modulator where an ARC-5 plate modulator should go.

> Brings up another thought, too.  I actually have one but it never 
> occurred to me to look, and it's currently two miles away.  What rack 
> series does the BC-950 fit?...
Standard SCR-274N rack.

> And which modulator did it work with?  

The BC-456 modulator would have been there for the
HF transmitters.
As you noted, the BC-950 has it's own built-in 815 plate modulator.
You can see where this was removed in early runs of
the T-23/ARC-5 sets.  In the ARC-5, they solved the
differing levels of mod needed between HF and VHF sets
by padding down the modulator output when in VHF mode.
I don't have a 274N VHF manual,
so don't know how they switched-out the BC-456 screen
modulator.  If anyone does have this manual, I'd sure
pay for a copy.

73 DE Dave Stinson AB5S