[Milsurplus] Looking for a Navy ATD 9050-15,800 Tuning Unit

[Mike Morrow]

> Wondering if the same [rarity of 9050-15800 TU] olds true for the
> 200-540 tuning unit?

No, that's common in comparison.  The CRR-47207 tuning unit for 200 to 540 kHz is not rare...but it will take some searching.  I found one on ebay 15 years ago.  The CRR-47206 200 to 540 kHz antenna tuning unit is also required.

> I see in the preliminary ATD the unit pictured shows the same compliment of
> tuning units as I have (540-1500, 1500-3000, 3000-9050, 3000-9050).

  http://aafradio.org/docs/ATD.pdf

The manual in section 1-1-4 explicitly lists those as the standard supplied units.  The CRR-23280 remote channel selector sslects from one to another as a four-channel transmitter.

The ATD is a disappointing efforr by Bendix, reflecting aircraft transmitter technology solidly from the 1935-era.  The Bendix engineering design and management staff must have been amazed at the profound sophistcation of the Collins ATC, whose 1940 initial contract date was identical to that of the ATD.  It's too bad the USN during WWII never came up with a receiver worthy of pairing with the ATC.  That had to wait until the AN/ARC-25 (combo of AN/ART-13 and AN/ARR-15).

What is odd about tge ATD is that the CRR-47208 540 to 1500 kHz tuning unit was supplied standard instead of the CRR-47206 and CRR-47207.  The USN was attached to the 500 to 1500 kHz operating region, for reasons not well documented.

I have the units needed for a typical ATD installation:

ARB        195 to 9050 kHz Receiver, with ZB-3 mounted.
ATD        200 to 9050 kHz Transmitter
ZB-3       246 MHz Homing Adapter, mounted on and feeding ARB loop terminals
LM-13      CFI

Mike Hanz has an excerpt from a mid-WWII training book that shows limited use of the ATD:

  http://aafradio.org/docs/Navy-radio-gear-1943.pdf

Mike / KK5F