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Re: [RFI] 80hz pulsating noise.

To: rfi@contesting.com
Subject: Re: [RFI] 80hz pulsating noise.
From: Colman Ahern <Smokey@ziplink.net>
Reply-to: Smokey@ziplink.net
Date: Mon, 31 Dec 2007 11:07:56 -0800
List-post: <mailto:rfi@contesting.com>
I was wondering if the lister of the post below my email ever found 
the source of this RFI?

Periodically I have a very strong noise at my receiving location in 
Berkeley calif.  The below post is the closest description I've found 
on the list.

The noise which I pickup is very simular to a recording of CODAR radar 
available for listening on the RFI noise website.  I had thought at 
first that it was coming from a neighbour's house.  However, reading 
about CODAR on the web has raised the possibility of there being a 
nearby CODAR transmitter/receiver installation.  I live not to far 
east of the Berkeley Marina, a news story said that one of these was 
to be erected at the Marina sometime in 2006 as part of a chain 
running the entire length of the US west coast.

In my case you can tune to any HF band you like, it will show up as a 
very strong signal.

Here's a link to the manufacturer:


It just makes no sense to me that the company would produce something 
which is such an offensive source of RFI in the HF bands.  Perhaps a 
defective installation with feedline or common-mode radiation where it 
should not exist?  A temporary set-up with no proper shielding?  An 
antenna radiating/receiving pattern aimed the wrong way?  What I hear 
is at 85 pulses per sec.

Happy new year.

Colman Ahern.

[RFI] DSL RF pulsing centered at 20.5 MHz
from [Jay Bareman] [Permanent Link][Original]
To: <rfi@contesting.com>
Subject: [RFI] DSL RF pulsing centered at 20.5 MHz
From: "Jay Bareman" <Radio_Q@mchsi.com>
Date: Thu, 24 Nov 2005 12:06:04 -0600
List-post: <mailto:rfi@contesting.com>

I am hearing signals that are pulsing in nature with a rep rate of 
about 80
a minute, clearly not on a 1 second interval like a clock might be using.
There is no particular center frequency although it disrupts the entire 15
meter band. Watching the bandscope on my receiver shows the pulse in a
different part of the band every time it occurs which just confirms to 
me it
is a broad band signal, or a transient pulse.  It appears strongest at 
20.5 MHz and clearly with a vertical polarization.  The signals peak at
about S8 to S9 (with no preamps) on a force 12 vertical dipole mounted 
in my
attic and horizontal antenna's will greatly reduce the signal.

I started DF'ing the signal and wound up at a neighbors house about 6 
away, maybe 750 feet.  The signal is very strong at his telephone company
Network Interface Box where he has a white cable plugged into it that goes
into an air vent on the side of the house.

I have not approached him yet but wanted to get some ideas from the 
group if
others have found anything like this.  We have SBC DSL lines in the 
area and
I suspect that is what he is using.

I tried the SBC tech support on the internet and that led nowhere.

Ideas or experiences or suggestions.


Jim  K5QQ

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