[Lowfer] 29.5 kHz historical

[David L. Wilson]

With WH2XBA/2 on 29.499 kHz, I thought I would give a little history of 29.5
KHz, 1 kHz away.  Back around 1970 or so when I first tuned there using a
converter I built with a 6BE6 tube feeding an E. H. Scott 20 tube "antique"
radio I bought for $10 at a flea market and a 50 ft antenna, I found a
signal centered on 34.5 kHz (later moved to 29.5 kHz --se below).  The radio
had a "tuning" push button that I fastened down--in reality the "tuning" was
a BFO which fortunately allow ssb, cw, and RTTY operation though it was not
designed for that.   The signal on 34.5 kHz sounded like FSK cw and for
hours would what sounded like "VE  ES" in cw and occasionally longer
messages that which others identified as encrypted cw.  I built a loop
antenna from 3 ft lengths of telephone wire with literally hundreds of
splices and DF'ed the signal to the west.   I lived in Ohio at the time and
conjectured the transmission came from the Strategic Air Command (SAC) in
Nebraska.   I wrote them a letter and they denied it was them.   After a
year of more DF'ing, I was convinced it was them, and writing them again,
they confirmed this time and sent me information identifying the
transmission as being from the SLFCS (Survivable Low Frequency Communication
System) station in Silver Creek, NE with 110 kW.   They operated a second
station at Hawes, CA on 37.2 kHz.   About that time, I acquired a new
surplused NSA ink-paper recorder.   I hooked that up and recorded the
transmission to the paper strip (I still have a piece of that from that
effort).  Splattering ink around my bedroom, I was able to discover what I
was seeing was 5 (not a typo) Bd 50 Hz shift Baudot RTTY.  The "VE ES" was 5
Bd Baudot RY's with some blank characters inserted.   This station later
moved to 29.5 kHz and later 48.5 kHz before it and the Hawes CA also were
shut down.   Besides 5 Bd Baudot, they also used 50 Bd  FSK Baudot and 200
Bd MSK.  They would transmit messages in all 3 modes (similar to what TACAMO
does today but TACAMO uses a 400 Bd MSK for the third mode instead of 5 Bd
FSK).  I have not seen anyone else besides these two stations use 5 Bd.  So
the current slow modes used on 29.499 take me back yeasrs ago to when I
copied 5 Bd/50 Hz shift Baudot centered just 1 Hz away on 29.5 kHz.

The 5 Bd mode was obviously chosen for similar reasons as some of the modes
being experimented with today.
--
David L. Wilson