I'd love to see that graph, or the measured data, if you still have it. It may
be useful on RFI web pages or publications.
-----Original Message-----
From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of David Cole
Sent: Monday, July 27, 2015 10:14 PM
To: rfi@contesting.com
Subject: Re: [RFI] Other Noise Challenge For Ed!
Joe,
A few years ago, I had a RFI source from an area with underground utilities. I
located a source by driving to each underground transformer and taking a
reading at 7 MHz, using a short antenna and a standard procedure for pointing
etc. I wanted to have a standard way of reading the signal levels. I did the
same thing at each transformer I could find, then took the data and plotted it
on a Google map of the area, then hand drew contour curves to the various S
meter levels I had gotten... Much to my surprise it formed a great big target
ellipse. I think I got very lucky, but it might be worth a try for you. I
then walked around with a 123MHz beam and TH-F6 in the suspect area.
Found the house in short order... Contacted the owner, and a few weeks later
the RFI was gone.
As Ed said, in each case, "First Contact" is so important... If you come on
strong, and tell the person they are in violation of anything, they get really
quiet... If you approach them as a neighbor, things go really well...
--
Thanks and 73's,
For equipment, and software setups and reviews see:
www.nk7z.net
For MixW support see;
http://groups.yahoo.com/neo/groups/mixw/info
For Dopplergram information see:
http://groups.yahoo.com/neo/groups/dopplergram/info
For MM-SSTV see:
http://groups.yahoo.com/neo/groups/MM-SSTV/info
On Mon, 2015-07-27 at 18:09 -0700, Joe Wolfe wrote:
>
> Ed, perhaps you can shed some sense to this. Up until 4 years ago, I
> had no noise to speak of...1 to 2 s units, tops.
>
> Then, one November day, I turned on the radio to 40 meters (7.205), at
> noon, and was blasted with a 20 over *white noise*.
>
> Did not go away, and it permeated 75 meters as well. 20 and 17 are
> tolerable, 15 and up have acceptable noise levels.
>
> Again, this is just very loud white noise, unwavering in pitch.
>
> I hooked my radio (Kenwood TS-2000) to a battery, then switched of the
> main breaker, so no power was present in the house. Noise was unchanged.
>
> Further research revealed: On 40, the noise dropped to below 3 S
> units, and stayed low all night. Around 9-10 in the morning, the
> noise starts to rise, reaching its crescendo around noon. 75 meter
> noise does not decrease much, at any time of day or night.
>
> I have walked the neighborhood with the AM radio, Kenwood TH-F6A, and
> found....nothing.
>
> The noise is present in all HF radios I have, Drake's, Yaesu's, even
> tried an ICom..
>
> Mobile HF, drive 2 miles away, and the noise is gone.
>
> There are no overhead wires in my neighborhood. There is a high
> tension line 2 miles from the house, but it is quiet it's 8 miles run,
> down to town from the crest of the mountain it comes across from the
> North. (I have driven it)
>
> I run an off-center fed dipole, 6 to 80 meters, at 20 feet on 1 side,
> 26 feet the other side. (Fence is on a drop down berm..we live in the
> hills (Each house in the neighborhood is 6 to 8 feet higher [or lower]
> than its
> neighbor]) I have no problems being heard anywhere, on any band,
> but...heh, if you can't hear, what the sense?!!!
>
> Thoughts?
>
> Joe Wolfe - W7RKN
>
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