[Milsurplus] ATC - ART-13 LF Oscillators

[Mike Morrow]

>Now is this correct: did the Navy only really have the ATC/ART-13
>with the O-??? LF oscillator?

The USN ATC (COL-52286) utilizes a LF/MF oscillator (200 to 1500 kc in six bands) that never had, to my knowledge, an official USN COL-52xxx component ID assigned.

The USN AN/ART-13 (T-47/ART-13) utilizes the same LF/MF oscillator as the ATC, with a JAN nomenclature of O-16/ART-13.

The USAAF/USAF AN/ART-13A (T-47A/ART-13) utilizes a similar LF/MF oscillator (200 to 600 kc in three bands), with a JAN nomenclature of O-17/ART-13A.

The USAF early AN/ART-13B uses a T-47A/ART-13 with CDA-T LF/MF/HF crystal control unit in place of the LF/MF oscillator.

The USAF later AN/ART-13B uses a T-412/ART-13B with CDA-T LF/MF/HF crystal control unit in place of the LF/MF oscillator, and a LF (actually MF) range-extend switch added to the front panel of the transmitter.

To use the full range of the O-16/ART-13, one of two external LF/MF tank networks is required (CU-25/ART-13 for 200 to 600 kc, CU-26/ART-13 for 500 to 1500 kc, usually with the SA-22/ART-13 antenna relay/switch box).

To use the O-17/ART-13A, an external LF/MF tank network is required. (The CU-25/ART-13 with SA-22/ART-13 for 200 to 600 kc was used for early installations.  That was later replaced by the CU-32/ART-13A, which incorporates larger reactive components and the the functions of the SA-22 all in one box that is actually larger than the transmitter.)

It's interesting that AN/ART-13A manuals state that, using the standard LF/MF aircraft trailing-wire antenna, typical power output at 200 kc is 4.0 watts (!), and only 14.5 watts at 500 kc.

The one USAF aircraft that I rode in 1970 that still had the AN/ARC-8 installed also had the LF/MF components.  I've seen several photos of USAF AN/ARC-8 installations.  Some had the LF/MF components, some did not.  It appears that the USAAF/USAF did indeed make use of the LF/MF coverage.

One of the nice things about the USAAF use of the AN/ARR-11 (BC-348) with the AN/ART-13A (T-47A) to create the AN/ARC-8 is that receiver LF/MF coverage (200 to 500 kc) and MF/HF coverage (1500 to 18000 kc) very closely matches the coverage of the transmitter with LF/MF oscillator installed (200 to 600 kc, 2000 to 18100 kc).

Mike / KK5F