Re: LF: Re: 135.92 warning

["Scott Tilley, VE7TIL" <sthed475@telus.net>]

Hey Jay

Care should be taken when measuring the strenght of that CA station... From 
time to time it stops modulation for seemingly random periods of time and may 
idle on either carrier freq, which one? seems random to me... I include three 
plots on my Spec Lab plot to detect this.  Two are measuring the peak in a 
narrow BW around each carrier.  The third is measuring the average signal 
strenght of the 50Hz BW signal (maybe abit more I can't remember as the plotter 
is at home...)  I also look at a spot about 100Hz above and below for the noise 
floor measurement of anything less and the noise floor varies with its signal 
strenght... This seems like a good setup for monitoring from here...
I find the signal is at our noise floor during the day (s0-s1) and peaks at 
night at over +30db over S9 on my rig. 

I've noted correlations between flares and its signal strenght as well...

Back to trying to work that pesky ZL...

73 Scott



Quoting Jay Rusgrove <JRusgrove@comcast.net>:

> 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: rsgb_lf_group@blacksheep.org 
>   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