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Author Topic: 5235 KHz sweeper  (Read 1911 times)

Offline Teotwaki

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5235 KHz sweeper
« on: May 16, 2014, 0509 UTC »
This signal is on 24/7 and I have a fleeting memory of being told that it is part of an ocean wave height sensor system along the California coast. Could be wrong  ;D
It sweeps from 5220 to 5250
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline Token

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Re: 5235 KHz sweeper
« Reply #1 on: May 16, 2014, 1451 UTC »
This is called CODAR, a specialized form of radar that maps / plots ocean currents and wave action.  Yes, there are many along the California coast, but there are hundreds located around the World, so it is a world wide issue.  Despite the fact I am 100 miles inland in the Mojave Desert I hear several hear at the house 24 hours a day.  You will find them on many frequencies, from 3 to 30 MHz, with most of them lumped in bands in the 4-5 MHz, 12-14 MHz, and 25+ MHz areas.

T!
T!
Mojave Desert, California USA

Offline sat_dxer

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Re: 5235 KHz sweeper
« Reply #2 on: May 16, 2014, 1909 UTC »
Remember Duga-3 aka the Russian Woodpecker from back in the 1980's?


http://www.youtube.com/watch?v=hH6C0kun5DU


http://www.youtube.com/watch?v=PAkoTCAEYAQ
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addendum
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Back in the good ol' bad days of the late Cold War, AEA had a "Moscow Muffler" which was a Woodpecker Blanker[1] in two models :WB-1 (receivers) & WB-1C for transceivers. The accessory was direct insertion between the radio and the antenna and claiming to be more effective than I.F. type blankers with no mods needed. Unit run on 12VDC @ 575mA likely from a wall wart?

http://www.casualham.com/wp-content/uploads/2013/08/wb1.jpg

Can still find a few show up on fea-bay sometimes.

[1] Vol. 38; 1984 World Radio TV Handbook article on pp597-598
« Last Edit: June 21, 2014, 0244 UTC by sat_dxer »
Most times & frequencies posted are only an approximation.
Due to adulteration of the E.N.I.G.M.A. "designators" by others and not a match in the Conet Project they are never used.
-30-

Offline Teotwaki

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Re: 5235 KHz sweeper
« Reply #3 on: May 16, 2014, 2054 UTC »
Remember Duga-3 aka the Russian Woodpecker from back in the 1980's?

Yes I do recall that signal!   ;D
Jim
NRD-525, Elecraft KX3 and Elecraft PX3 Spectrum Display
76' end fed long wire & 66' off-center fed dipole for 10/20/40 meters
Orange County, SoCal, The better half

Offline Token

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Re: 5235 KHz sweeper
« Reply #4 on: May 19, 2014, 1808 UTC »
Remember Duga-3 aka the Russian Woodpecker from back in the 1980's?
 

I remember hearing this for the first time in 76 or 77.  The signal was more complex than most people were / are aware, and this complexity contributed to the wide bandwidths it hammered.  In addition to the sin(X)/X spectrum of the pulsed signal the Woodpecker was often frequency hopping within one pulse repetition interval.  It was not uncommon for the system to hit 4 frequencies every 100 msec, sometimes 100’s of kHz between freqs.

It is somewhat odd how often in the last 10 or so years I have heard “the Russian Woodpecker is back!” from SW listeners.  Of course, it is not back, the stations have been dismantled (only two of the 12 antenna structures, and so half of one radar system, still stand).  But several other systems appear / have appeared that have a similar 10 Hz rep rate, and they are sometimes confused, normally by people who do not remember the old system well, for the “Woodpecker”.  And some new listeners seem to call any pulsed or presumed radar signal “Woodpecker”.

About the closest modern signal to the old Woodpecker (NATO reporting name “Steel Yard”) would be the ionosonde to the new’ish Russian 29B6 radar.  The 29B6 itself sounds nothing like the Woodpecker, but the sounder does have a 10 Hz rep rate, similar to the WP.  The sounder is much narrower banded though, and is an LFMCW transmission, vs pulsed, so it is much less disruptive to other users of the spectrum.  Other than the fact it repeats at 10 Hz the sound of the signal itself is not very similar to the old WP.

T!
T!
Mojave Desert, California USA

Offline sat_dxer

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Re: 5235 KHz sweeper
« Reply #5 on: May 19, 2014, 2351 UTC »
Points of clarification:
The “Woodpecker” was heard from the mid-1970’s by this poster, it was exposed more so by the popular radio hobbyist press and others into the 1980s in parallel to the rise of political hardliners and others seeking to market “filtered” solutions.

In posting the (do u remember) comment, it was never suggested that the “Woodpecker is back!”
« Last Edit: May 20, 2014, 0009 UTC by sat_dxer »
Most times & frequencies posted are only an approximation.
Due to adulteration of the E.N.I.G.M.A. "designators" by others and not a match in the Conet Project they are never used.
-30-

Offline Token

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Re: 5235 KHz sweeper
« Reply #6 on: May 20, 2014, 0013 UTC »

In posting the (do u remember) comment, it was never suggested that the “Woodpecker is back!”


My post was not meant to imply that anyone here was suggesting the Woodpecker was back.  It was only a passing comment along the thread of things "Woodpecker" and to point out one of the specific non-Woodpecker signals that can sound somewhat Woodpecker'ish.

T!
« Last Edit: May 20, 2014, 0016 UTC by Token »
T!
Mojave Desert, California USA