Frank,
Could you supply some data of what you use, and how you use it? I know
it would help me to see what someone with more experience does, and
uses.
--
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 Wed, 2015-07-29 at 11:44 -0400, Frank N. Haas KB4T wrote:
> I am not an engineer. I do have many years of successful DFing
> experience locating a wide variety of interference sources.
>
> The method David used to locate his 7 MHz source in an area supplied
> by underground utilities is more sophisticated than my approach and
> likely resulted in finding the source faster than I would have.
> However, the underlying concept is the same as I have often promoted
> on the RFI list.
>
> That is, locating a source can be accomplished by using the right
> tools to hear the source and get directional indications that will
> lead you to it. In short, DFing the source, no matter what frequency
> it may be on.
>
>
> If an interference signal is very strong (over S9) on the affected
> receiver and it is present continuously, it should be easy to pinpoint
> using good tools. Directional antennas are available for all
> frequencies between 1.6 MHz and 1 GHz. While it would be nice if one
> antenna system could do it all, that simply isn't the case.
> Fortunately, there are good receivers with signal strength indicators
> and built-in attenuators that cover that frequency range. Antennas
> that cover segments of the spectrum can be built or bought.
>
>
> I work as an Interference Investigator for a large electric utility in
> Florida. Over the years, I have put together a small but effective
> collection of antennas and receivers that allow me to search for
> sources all across the spectrum. It has been said that DFing signals
> in the 1.6 to 30 MHz range can be challenging. Without good tools,
> that statement is true. But good tools for HF DFing can be had for
> less than $500.
>
>
> This is an area where ham radio clubs can shine again. Decades ago,
> radio clubs had committees dedicated to helping hams who had "TVI"
> problems. TeleVision Interference was a pretty common problem long
> ago. Modern conveniences like Cable TV and Satellite TV have largely
> eliminated the problem. Instead we have the opposite problem today.
> Our stations are being dramatically impacted by consumer electronic
> devices and faulty power line devices. Instead of our neighbors coming
> to us complaining, the tables have turned and now we often have to
> approach our neighbors.
>
>
> As has been recently pointed out here, approaching "lay persons" about
> interference problems is an art all its own. Radio clubs can usually
> afford to build a collection of good tools. Regular practice builds
> competence. The increasing number of interference issues provide ample
> opportunities for practice. Club members with great interpersonal
> skills can be the diplomats who intercede and smooth the process of
> resolution.
>
>
> I see Interference Resolution as an area that can build radio club
> involvement and participation. I still firmly believe that increasing
> radio spectrum pollution is a problem for which the ham radio
> community must be better equipped.
>
>
> For Joe, if there is no local club or local interference support,
> building an HF DFing kit, practicing its use and getting competent at
> zeroing in on sources may be fun, if not necessary.
>
>
> Frank N. Haas KB4T
>
> Utility Interference Investigator
>
> Florida
>
>
>
>
> On Tue, Jul 28, 2015 at 2:06 PM, David Cole <dave@nk7z.net> wrote:
> Hi Ed,
> Sorry, but I no longer have it... It was ugly and hand drawn
> contour
> lines... I now use Google Maps and GIMP to draw things...
> They look
> much better that way!
>
> If you want, I can send you, (not on the list), the package of
> data I
> collect for the FCC should a RFI situation get out of hand,
> and need to
> be reported...
>
> BTW, the walk around was at 135 MHz, just above the Aircraft
> band in AM
> mode... I use one of those little MFJ 135 MHz broadband VHF
> beams,
> works like a champ most of the time.
>
> --
> 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 Tue, 2015-07-28 at 17:57 +0000, Hare, Ed W1RFI wrote:
> > 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
> > >
> > > _______________________________________________
> > > 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
>
> _______________________________________________
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> http://lists.contesting.com/mailman/listinfo/rfi
>
>
>
>
> --
> Frank N. Haas KB4T
> Utility Interference Investigator
> Florida
>
>
>
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