Part 2 LF & MF Communications Equipment Aboard USS Ling (SS-297)
Part 3 LF & MF Communications Equipment Aboard USS Ling (SS-297)
Part 4 LF & MF Communications Equipment Aboard USS Ling (SS-297)
Part 5 LF & MF Communications Equipment Aboard USS Ling (SS-297)
This
article represents an extraordinary blend of talents from within an
amateur radio association and an organization attempting to preserve the
history of the US Nary. No doubt with perseverance these committed
workers will be able to totally restore a very interesting and important
part of naval and radio communications history. Hats off to their
dedicated effort!
For
almost two years members of the 10-70 Repeater
Association, Inc. of NJ have been working on restoring radio and other
electronic equipment aboard the WW2 - commissioned submarine USS Ling
(SS-297)1. The Ling is berthed at the NJ Naval Museum in
Hackensack, NJ. Of particular interest to this column is the LF/MF
equipment aboard the sub. The main items used (as in most other
Balao class submarines) are the RAK-8 and RAL-7 receivers and the
TBL-12 transmitter, or various
series of the same gear. The LF/MF gear would have been used to monitor
the 500 kHz international distress and calling frequency and for
communications with Coast Guard and commercial stations as required.
Most Navy shore stations maintained a "guard" (dedicated transmit and receive) on 500 kHz, plus a frequency close to 500, as well as on various US Navy operations theater or worldwide working frequencies. The US Navy normally used
LF/MF
for weather, navigational, and distress purposes, not for regular
message traffic. Commercial vessels, on the other hand, regularly used
500 kHz as a calling frequency, and moved to other frequencies within
the LF, MF, and HF bands to pass traffic.
The
RAK/RAL receivers are unusual for the period because they are TRF (tuned
radio frequency) receivers with a regenerative detector. Performance is excellent considering their 1930s design. They
are classified as "radiation safe," that is, oscillation from
the regenerative detector cannot be readily detected outside the sub.
The
receivers use only six tubes, 4 each 606 and two each #41 pentodes. The
RAK receiver tunes 15 to 600 kHz in six bands, and its MF/HF brother the
RAL tunes 300 kHz to 23 MHz in nine bands.
1 See http://www.njnm.com/ for additional information on the New Jersey Naval Museum and a virtual tour of the Ling.
