Hi Don,
I must agree with you here...
I have only once or twice guessed what something was in over 10 years of
hunting RFI, based solely on the RFI signature... I have guessed based
on timings of the on/off etc., and been correct... But, based on just
the RF signature, not so often...
It all boils down to understanding what you are looking at, then getting
out an antenna and looking for that particular signal...
There are some items that can be "inferred" by an RFI signature, but it
is very general in nature...
Things like interference that comes on each morning, then shifts a few
minutes each day... Probably something controlled by sun light, yard
lights, solar, etc.
Something that comes on at precisely the same instant every night, and
ends at the same instant each morning, probably something like a
lighting array, but probably not solar.
Very general inferences are very helpful in locating RFI... But pinning
to a source, not likely on a regular basis...
For the fellow looking at his RFI, see:
https://www.nk7z.net/i-have-rfi-now-what-locating-it/
and/or
http://www.k9yc.com/publish.htm
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
On 11/2/19 5:08 AM, Don Kirk wrote:
Hi Frank and gang,
I see lots of folks on the RFI reflector "wondering what an interference
waveform might be from", and honestly after many years of tracking down RFI
I have found that guessing what the source might be is almost counter
productive, except for understanding if the noise source might be power
line noise as that helps me determine what DF gear to pack. What works
best for me is "boots on the ground', meaning that I get out DF gear (radio
direction finding gear), and then track down the property that's generating
the noise, and then we locate (track down) the offending device within that
property. I find it much better to keep an open mind regarding what the
source might be.
Just my opinion based on many years of tracking down sources of RFI.
Tracking down RFI has unfortunately become a main part of my ham radio
hobby.
73,
Don (wd8dsb)
On Fri, Nov 1, 2019 at 7:30 PM Frank O'Donnell <vfo@inkbox.net> wrote:
Hi all, new to this list, hoping to learn enough to chase down some of
my yet-unsolved RFI issues.
As a start, I'm wondering if the way that RFI I saw the other morning
appeared in the receiver's waterfall might suggest anything about what
the source of noise could be.
Here are two brief video clips from SDR Console, displaying a waterfall
covering the LF/MF spectrum with input from an Elad FDM-S2 SDR and
broadband vertical antenna.
The first clip is at 6:08 a.m. PDT, exactly one hour before local sunrise:
https://vimeo.com/370416556/e3cf9bcb09
At 00:23 of that clip, a pattern of heavy RFI starts, with lines in the
waterfall spaced ~16 kHz apart (approx 6 lines per 100 kHz).
A couple of minutes later, I noticed that the RFI started toggling, with
the pattern changing for a second or two, and then the RFI disappearing
briefly before restarting. In the following clip this pattern starts at
00:09:
https://vimeo.com/370418392/afb0a0c4ef
Any thoughts? We live in a suburban neighborhood where lots are all
approx 50 x 200 feet. There are at least two houses with solar panels
within ~200 feet of us, and more down the block. I gather that RFI from
solar panels can vary, based on the type of system and the deficiency
responsible for the RFI. Do these clips show any kind of visual
signature that might suggest the source?
Thanks and 73,
Frank K6FOD
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|