[Milsurplus] USN Transmitters on 500 to 1500 kHz

[Mike Morrow]

>> I have a new condition ATD, no accs.
>> I also saw a 500-1500 separate (used ) TU. Immediately i thought, make the 
>> non-existant 9-15 Mc/s tuning unit out of this, but that might be a stretch.
>
>Don't give up-  I found the "unobtainium" LF tuning unit.
>I'll bet the 9-15 MC one is out there still.

One wonders why new ATDs came with a 500 to 1500 kHz tuning unit in
channel 1 rather than a 200 to 500 kHz unit.  They came from the
factory with the external 200 to 500 kHz antenna coil, but not the
tuning unit for that range.

It appears that for a while the USN thought that transmitter coverage
of 500 to 1500 kHz was of special value (over 200 to 500 kHz), for
which we have:

(1) The ATC with optional 200 to 1500 kHz oscillator
    and 500 to 1500 kHz external PA tank coil,
(2) The ATD as supplied from the factory, and
(3) The T-15, T-16, and T-17/ARC-5 units.

I wonder why.

I was able to find a 200 to 500 kHz ATD tuning unit on ebay a couple
of years ago to go with an otherwise complete ATD system.  I've got
complete ARB, LM-20, and ZB-3 sets to go with it.

I doubt that the ATD ever saw much actual utilization in naval service,
so new-condition ATDs seem to be most common.  New ARBs are much harder
to find.

I've never seen the rare 9 to 18 MHz ATD tuning unit.

Mike / KK5F