John & the group
Interesting you should mention this. I've been plotting NPG the past couple
weeks ala W3EEE DCF39 style graph. The signal is quite strong typically
showing up at 0100Z and fading out an hour or so after local sunrise. The
signal is strong enough that the frequencies between .925 and .975 become
filled with 'white' on an Argo screen. In order to get to a truly clean noise
floor for the noise channel measurement it was necessary to move at least 25
kHz outside the carriers.
An early sample before timing issues were sorted out is here:
http://www.advancedreceiver.com/capture/NPG1.jpg
Had been planning to make this into a 'permanent' upload for propagation
study in the next week or so...if there is any interest.
A contact at DOD verified it as Dixon CA running 40 kW.
Jay
----- Original Message -----
From: John Andrews
To: [email protected]
Sent: Wednesday, October 05, 2005 9:32 AM
Subject: LF: 135.92 warning
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
