Re: QRM noise on 7070.0 + a bit more

Bill Garwood

Yep, that woodpecker would wipe out just about every QSO for a while.  It seemed to start up just about when I'd try to work some new DX.  I was mostly CW back then as well.  Rumors were that some of that might have been someone other than the Russians as part of the DEW line and OTH radar in Canada and Alaska.


I have an old Kenwood that has two noise blanker filters.  One is especially designed for the woodpecker and did a fairly good job depending on how strong the ham signal was in relation to the woodpecker.


Happy Radio!



From: 070@... <070@...> on behalf of 'Milton Garb' n6mg@... [070] <070@...>
Sent: Thursday, December 17, 2015 7:59 PM
To: 070@...
Subject: [070] QRM noise on 7070.0 + a bit more

Bill, do you remember the “woodpecker” from the late 1970’s?

That was supposed to be “over the horizon” radar from the USSR...

I wasn’t really into SSB back then, but it raised hell on 20m cw!




From: 070@... [mailto:070@...]
Sent: Thursday, December 17, 2015 11:28 AM
To: 070@...
Subject: Re: [070] Pulksing QRM noise on 7070.0



I occasionally see and hear some pulsing noise on 40 - 30 and 15 meters.  It will give a bunch of traces on the waterfall.  This is supposedly some kind of military radar operated in the middle East, Russia, Iran or wherever the latest twitter feed says it is coming from.  Lasts for a while then goes away.  Sometimes it fades up and down along with the DX stations so it is probably a long way from here.  I saw it a few days ago on 7.040 but 7.070 was clean.  I'm on the east coast so it is doubtful whatever you are seeing on 40 is from the same source as what I see.  But.. there might be some kind of radar undergoing testing on the west coast.


Years ago, I was working in an avionics repair shop.  A couple of miles away was a manufacturer of military aerostats (tethered "blimps").  They were supposedly testing high power radar from those aerostats, several Megawatts pulsed, for over the horizon use in the middle east.  When they would fire up the aerostat, the oscilloscopes would fill up with traces and some of the comms equipment would act up.  We had to wait until it quit to make some critical measurements and adjustments.  Guys listening to portable radios on their workbenches would get interference to their broadcast programs that sounded similar to a "buzzsaw". 


Besides military contractors; plating shops, high powered pulse welders, foundries and a lot of medical equipment can put out some nasty RFI on occasion.  The source may be a few miles away or a whole lot further.




Bill N4GBK




From: 070@... <070@...> on behalf of Kevin Lemon k0mci@... [070] <070@...>
Sent: Thursday, December 17, 2015 5:48 PM
To: 070@...
Subject: Re: [070] Pulksing QRM noise on 7070.0



Isn't there one of those electronic music rave festivals going on this week? 



I'm hearing an S9+20 db pulsing noise on 40 meters. Anyone else hearing it?

What the heck can it be?



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