[Milsurplus] ART-13 and 51S1 pairing

[Mike Morrow]

The CDA-T crystal unit (with 20 MF/HF, 4 LF/MF crystal controlled channels) is very positively identified in common military use in any instruction book that includes the AN/ART-13B. That B series exists in several versions built on existing earlier transmitters:

(1) ATC/COL-52286A or T-47/ART-13 or T-47A/ART-13 transmitters to which the CDA-T has been added.
The original nomenclatures plate is unchanged.

(2) ATC/COL-52286A or T-47/ART-13 or T-47A/ART-13 transmitters to which the CDA-T has been added
---AND---
The LF EXTENDED FREQUENCY RANGE switch has been added.
This version has a new nomenclature assigned of
T-412/ART-13B.

The T-412's LF EXTENDED FREQUENCY RANGE switch adds one additional capacitor to the driver stage that allow transmitter operation using MF/HF crystals in the CDA-T for frequencies between 1680 and 2000 kHz.  In spite of the LF EFR switch's misleading label, it has nothing to do with operation on one of the CDA-T's four LF/MF channels.

The most capable T-412 is one built from a T-47A, because the T-47A has improvements over the earlier ATC and T-47 versions, including the VFO Dial B vernier scale that allows VFO setting precision of 1 kHz for the entire MF/HF range.

The T-412 in this HU-16 lacks the vernier scale, so it has been built on an old USN ATC or T-47.

It is interesting that the AN/ARC-8 installation has had its AN/ARR-11 (BC-348-*) replaced by the 51S-1, with little doubt making it a very few of its kind non-standard configuration.  The substitution is made easier by the 51S-1 receiver's ability to use 400 Hz AC power.

The 618T installation is with little doubt the
RT-648/ARC-94 (618T-2) 400 watt HF set, which used  400 Hz AC as its primary power.

There are a lot of other interesting things vissible, like dual AN/ARN-6 ADFs, AN/APX-25 IFF  and AN/APN-9 LORAN A.

Mike / KK5F

-----Original Message-----
From: Ray Fantini <rafantini at salisbury.edu></rafantini at salisbury.edu>
Sent: Aug 26, 2022 3:49 PM
To: milsurplus at mailman.qth.net <milsurplus at mailman.qth.net>, mrca at mailman.qth.net <mrca at mailman.qth.net></mrca at mailman.qth.net></milsurplus at mailman.qth.net>
Subject: [Milsurplus] ART-13 and 51S1 pairing

It&rsquo;s a Friday, always an opportunity to visit (virtually) The National Museum of the United States Air Force in Dayton and look around. Thought this series of interior shots of their HU-16B Albatross was of interest. Look at the pairing of an ART-13 transmitter with a 51S1, both Collins radios but a generation or two apart, also the ART-13 has a Comco Crystal Oscillator in it that many have speculated were only used in civilian service. If you download the individual pictures you can read the sheet on the transmitter that list both the preset channels on the transmitter and the crystal channels, oddly 2182 the old international distress channel was set on the VFO as a preset and not one of the rocks. Also, maybe someone can clarify what the low frequency extend range switch is for?
The 51S1 is set to USB and that makes more sense when you look and see that just below it is a 618T.
Before anyone starts saying how this is all wrong remember that we are talking about the US Air Force Museum and if they have it displayed this way would tend to think it&rsquo;s so.
Look at:

https://www.nationalmuseum.af.mil/Upcoming/Photos/igpage/26/

https://www.nationalmuseum.af.mil/Upcoming/Photos/igphoto/2002928488/

https://www.nationalmuseum.af.mil/Upcoming/Photos/igphoto/2002928458/

There is a link to download the image in a higher resolution version at the bottom of each page.

Ray F/KA3EKH


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