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.
[RFI] DSL RF pulsing centered at 20.5 MHz
from [Jay Bareman] [Permanent Link][Original]
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
I am hearing signals that are pulsing in nature with a rep rate of
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
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
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
others have found anything like this. We have SBC DSL lines in the
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.
RFI mailing list