[Milsurplus] ART-13B Questions

Tue, 14 Oct 2003 15:53:44 -0600

I "think" there were remote control boxes that were modified to include =
an A-B switch.I have never seen one though.I once had all the blue =
prints and instructions to modify to the "B" model.There was a kit and =
it was stated to take 10 hours of shop sime to do it.Not for the weak of =
heart!Had a "B' unit once too.All gone to better homes now...
 Jay

-----Original Message-----
From: Morrow, Michael A. [mailto:[email protected]]
Sent: Tuesday, October 14, 2003 12:45 PM
To: [email protected]
Cc: [email protected]
Subject: RE: [Milsurplus] ART-13B Questions

Art Delibert / KB3FJO wrote:

> I just bought an ART-13B transmitter, with a crystal=20
> oscillator, and some things about it are perplexing.
>=20
> 1.  Selecting crystal freqencies:  There are 17 crystals (and=20
> space for 20)... But the crystal unit seems to be able=20
> to select only 8 frequencies.  There's a toggle switch marked=20
> A/B and a rotary switch marked 1-4.  So how does the user select
> among the 17 (or 20) crystal frequencies?

The normal transmitter channel select switch (just below the
antenna current meter) selects which of 10 HF crystals in the CDA-T
unit are in the circuit.  There are two banks of ten crystals in
the CDA-T.  Which bank of ten is in use is selected by the
A - B switch on the CDA-T.  Bank selection can only be done
locally at the transmitter, while selection of any of the ten
channels within the selected bank can be done remotely.

> 2.  Low Frequency Extended Range:  There's a toggle switch at=20
> the bottom center of the front panel and a plate next to it
> marked "Low Frequency Extended Range."  The 2 settings of the
> toggle switch are marked "Normal" and "Extended=20
> range."

NORMAL   - Used for crystal operation from 2 to 18 mcs
EXTENDED - Used for crystal operation from 1.67 to 2 mcs

There is also VFO - XTAL switch that would return HF operation
on the VFO when selected at the CDA-T.

> Also, I'm surprised to see any reference on this radio to "low=20
> frequency," because the crystal unit occupies the space that=20
> is usually reserved for the low-frequency oscillator.

The CDA-T has a 6AQ5 tube as the HF crystal oscillator, **AND**
a 1625 as a LF crystal oscillator.  The LF portion of the CDA-T
is in effect when LF is selected on the channel select switch
I mentioned above.  The CDA-T has a four position switch on its
front for manual local selection of one of four LF crystals.

> 3.  Carbon/Dynamic Mike:  The carbon/dynamic mike switch has=20
> been fixed permanently in the carbon position ... can I just
> unhook the switch and use it as it was originally meant to be
> used?

Lockwiring a switch whose position is not normally altered for
a particular installation is a very common military and=20
commercial practice.  Just go ahead and remove the lockwire and
position the switch as desired.

> Any info appreciated.  And I would be very interested in any=20
> manuals or articles that describe the ART-13B modifications.

You'll find a lot of detail on the CDA-T in the AN/ART-13 manuals
at: http://www.kg7bz.com/Manuals.html  They are in .pdf format,
so they come out close to the original in quality.

73,
Mike / KK5F
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