40 meter jamming (?) heard at 10 P.M. PST 9/23/09

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eHam.net Forum : RFI : 40 meter jamming (?) heard at 10 P.M. PST 9/23/09

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40 meter jamming (?) heard at 10 P.M. PST 9/23/09	Reply
by AL7GS on September 24, 2009	Mail this to a friend!
Last evening I turned on my Argo V and was surprised to hear what was reminiscent of a "woodpecker-like" s-7 to s-9 signal that seemed to peak at about 7.050 and was at least 100 kilohertz wide...anyone else hear this? Anyone have a clue as to its origin? There was some qsb on this thing. Hope this isn't local and that it goes away! Appreciate your comments! 73, Howard

RE: 40 meter jamming (?) heard at 10 P.M. PST 9/23/09	Reply
by WB5JEO on September 24, 2009	Mail this to a friend!
If it's what's been commonly heard for a long time, it's generally presumed to be OTH radar, possibly China, but there are other suspects. Much faster and more motor-like, rather than the pecker's tapping. Check about halfway down in the Radar section: http://www.iarums-r1.org/iarums/sound/main.html

RE: 40 meter jamming (?) heard at 10 P.M. PST 9/23/09	Reply
by KG4DGF on October 1, 2009	Mail this to a friend!
Speaking of 40, did anyone catch the jammin tunes on 7.110FM last night?

RE: 40 meter jamming (?) heard at 10 P.M. PST 9/23/09	Reply
by CA2VMP on December 14, 2009	Mail this to a friend!
i hear it all day long over the 40 meter band , normally sweeps from 6780 to 8400 Khz , and the signal is about 100 to 200 Khz wide S9+10 here in Chile South America .i ve ever heard it on portions On the CB band .

RE: 40 meter jamming (?) heard at 10 P.M. PST 9/23/09	Reply
by EI5CD on February 10, 2010	Mail this to a friend!
re 40m jamming I would like to know if this is a slow pulse type, as I have been hearing a 5 pulse per second signal across 7 and 8 MHz for a long time,relatively low level but enough to disturb weak signals. Not a harsh pulse like old 'Woodpecker' but more like chuff-chuff-chuff (helicopter blade). Also heard around 12 to 14MHz and from 19MHz up to beyond 25MHz at times, interfering with 21MHz. Also has a variation, about 6dB across 40kHz, ie max at 8000kHz,min at 8020kHz,max at 8040khZ etc. To hear it you need to have low background QRN, no CFLs,switch mode PSUs,plasma TV or other noisey electronics.My be from S E Asia, not a RADAR, very unusual transmission. Des WALSH EI5CD e-mail des.walsh@iaa.ie Feb 10 2010

RE: 40 meter jamming (?) heard at 10 P.M. PST 9/23/09	Reply
by WB5JEO on February 10, 2010	Mail this to a friend!
There's quite a variety of HF RADAR being used in oceanography, mostly mapping wave height and direction. As I understand it, the whole HF spectrum is used, because different wave heights effectively reflect different frequencies. Doppler shift detects wave direction. (Usually requiring two transmitter sites.) Pulse rate can be all the way down to 2 per second or very much faster. And surface wave HF surveillance RADARS can run pulse rates of 4 to 50 Hz. (The USSR's "woodpecker" was sky wave.)

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