Gary,
I have not gone the 'full distance' on these yet, you might say I have taken
the opportunity to use them as 'training missions' to perfect my DF skills and
test different DF receivers in tracking down low band and 80 meter 'bogeys'. I
have also been busy this year tracking down several power line noise sources
that cropped up that were much greater interferers and of more immediate
concern (+15 dB over S9 power line noise on my favorite band, 160 meters!) So
far out of four power line complaints three have been addressed by the power
company.
It should be added that DFing these low band signals presents a bit of
challenge when within a wavelength (about 500 feet on 160 meters) of the source
so this has been a valuable 'learning experience' on my part. One 'run' I made
on one of these sources involved the use of an ADF (automatic direction finder)
which utilizes a motor-driven loopstick antenna which actively 'points' to the
source; this was affixed to my bicycle basket (on the handlebars) and used in
one DF run. It should be noted these DF receivers need to be operated out in
the open, with the signal unobstructed both to the loopstick antenna and the
sense antenna. A bicycle is a natural choice in this case.
I had been wondering when someone else would be affected by these, as SURELY I
am not the only one that is within range of whatever it is that is being sold
commercially (and retail!) in quantity to the public.
Begin conjecture
Conjecture is that these are the invisible-fence/wireless dog collar
installations. It makes sense from the standpoint that 50 to over 200 feet of
wire is used (although buried) in the perimeter of the back yards of the
residences where these signals have been traced.
End conjecture
73,
Jim WB5WPA
From: Gary Smith <Gary@ka1j.com>
To: RFI@contesting.com
Sent: Sunday, October 2, 2016 8:34 PM
Subject: Re: [RFI] Regular birdies
Jim,
This will be a bugger I think. If... its
coming from the airport, they likely won't
let me go snooping around, not with
today's tightened security. I'll have to
take the back-up K3 out and see what I can
find but DFing these relatively faint sigs
on 80 & 160 will be a bugger.
Be easier if they showed up on all the
other bands, a DFing antenna would sure
help.
I see your interference and this does have
a whistling/wavering sound to them, they
don't drift but sometimes it almost sounds
like they're heterodyning.
What was it you found to be the source?
73,
Gary
KA1J
> Gary,
>
> I tracked down a "wavering carrier" I had on 160 meters to a residence
> 1.9 miles away to my north. This is in a city/suburban environment
> over relatively flat, but conductive (30 mS North Texas) earth. I make
> mention of this ONLY to give some idea of how far away these noise
> sources or signals can be! I notice you have 'humanity' (houses or
> homes on lots) west of you out past the airport about two miles or so
> distant.
>
> I tracked two other such "carriers" to two other discrete residences
> to my SSW and W at about 3700 ft and 4200 ft respectively. I have been
> out with different gear at different times to confirm this, using
> different receivers (including DF receivers) as well (i.e., I can
> circle the block and the DF antennas continue to indicate a specific
> residence). These 'carriers' are also receivable in the 80 meter band.
>
> Here is a sample of the carrier at it appears on 80 meters (it makes
> kind of a tea kettle whistle sound):
>
>
> https://www.youtube.com/watch?v=YkHt5iS9WIM
>
>
> I think you are going to have to track this down (the 'hard', old
> school way) as you indicted in your previous post in order to next
> identify the source.
>
>
> 73, Jim WB5WPA
>
>
> From: Gary Smith <Gary@ka1j.com>
> To: RFI@contesting.com
> Sent: Sunday, October 2, 2016 5:09 PM
> Subject: Re: [RFI] Regular birdies
>
> Unfortunately, these birdies are not from
> within this house.
>
> I killed the power to the house, ran the
> 12V equipment, the K3s and P3 from a
> battery and they still come out just as
> strong on both the vertical and the HI-Z 8
> element. There are some directions the
> HI-Z kills the birdies in.
>
> What is difficult for me to picture is,
> direction-wise, they seem to have a strong
> signal coming from the west but to the
> west is nothing but marsh, ocean, a
> peninsula, more salt water and finally an
> airport a couple miles away.
>
> http://tinyurl.com/jbac8wv
>
> Since this appears to come from a power
> supply or some electronic device and most
> likely close by, I'm at a loss. My nearest
> neighbors aren't the type to let someone
> into their house to sniff the air and I'm
> not going to deal with them at this point.
> What might be a workable but expensive
> solution is to find a NCC-1 and use both
> the 8 element HI-Z and the 3 element HI-Z
> to null out the interference.
>
> Now to see if I can find a used NCC-1 at a
> reasonable price.
>
> The beat goes on.
>
> 73,
>
> Gary
> KA1J
>
> > Not really sure that I'd call them birdies
> > but here is a family photo of them seen on
> > the P3:
> >
> > http://doctorgary.net/RFI-K3s.jpg
> >
> > they are regular at 8.02
> > 3.506.07 MHz
> > 3.514.09
> > 3,522.12
> > 3.530.14
> >
> > 8.02
> > 8.03
> > 8.02
> >
> > I see them with both the Inv-L and the Rx
> > antenna but much more pronounced on the
> > Inv-L
> >
> > They're not on all bands but I come across
> > this all too often. I've looked at the
> > coax connectors and all are tight. Any
> > suggestions?
> >
> > Thanks & 73,
> >
> > Gary
> > KA1J
> > _______________________________________________
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