The area around 135.922 kHz has been used for Europe to North America
transmission for several years. In May of 2005, a military TTY station in
California started using that part of the band. Following a tip from
Laurence last night, I noticed that the signal is quite loud in the eastern
U.S., and was clearly audible an hour after sunrise this morning.
They are using 50 Hz shift, with carriers on 135.925 and 135.975 kHz. I
don't know what the keying rate is, but the signal is appropriately wide.
Any of you planning transmissions to North America should consider moving
above 136 kHz if this operation continues. Since the east coast is subject
to interference from CFH on 137.00 kHz (+/- a few hundred Hz), there may be
an upper bound. Mercifully, the CFH operation is intermittent, and they have
been quiet since mid-summer. With a number of U.S. and Canadian beacon
stations running 24/7 in the 137.777 kHz range, it would also be advisable
to stay below 137.5 kHz.
John Andrews, W1TAG/WD2XES
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