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Re: [RFI] Investigating receive noise - got a few questions

To: Dave <dave@nk7z.net>
Subject: Re: [RFI] Investigating receive noise - got a few questions
From: David Eckhardt <davearea51a@gmail.com>
Date: Sun, 11 Nov 2018 01:24:37 +0000
List-post: <mailto:rfi@contesting.com>
We had an interesting instance in Loveland, Colorado:  Lots of interference
typical of a grow operation. We went to the neighborhood with receiver and
a small loop coupled to an AirSpy SDR.  About 20-minutes into sleuthing,
the interference want away, never to return. I believe someone running a
grow operation (pot is also legal in Colorado) saw us and shut it down.
Also afraid of being caught, so its never reappeared.   Didn't have to do
anything other than show up with proper equipment.

Dave - WØLEV

On Sun, Nov 11, 2018 at 1:16 AM Dave Cole (NK7Z) <dave@nk7z.net> wrote:

> Hi Andy,
>
> If you can, build a loop, and DF the source.  Use the null to pin down
> the direction.  That will help a lot.  Triangulate on it, and that will
> get you close.  Once close, see if you can hear the RFI on a VHF AM
> receiver.  If so, get a three element beam, and start hunting.
>
> Once you locate the source, you may want to contact the person living
> there, in the kindest of ways, and ask if you can verify the RFI is
> coming from his/her home.
>
> I always have a second ham with me when I contact an RFI source, but in
> Oregon, where pot is legal, 80% of the RFI not caused in my own shack,
> is related to grow lights, so I am cautions.
>
> 73s and thanks,
> Dave (NK7Z/NNR0DC)
> https://www.nk7z.net
> ARRL Technical Specialist
> ARRL Volunteer Examiner
> ARRL OOC for Oregon
>
> On 11/10/18 1:57 PM, Andy KU7T wrote:
> > Hi,
> > I am trying to sort out receive noise issues with my Flex.
> >
> > I am not exactly sure how clean the spectrum could/should be. I have the
> feeling that I may be more concerned about this just because I can see the
> spectrum.  I am in an residenial area with 5 acre lots, with miles to the
> next town and businesses. I always throught/hoped I have no noise issues.
> >
> > I took some time last night to turn off all breakers, one after another,
> until only the shack was left. Then I reduced everything in the shack so
> the only thing left was the 12V power supply, radio, computer and monitor.
> I also adjusted the noise offset on the Alinco Powersupply with no changes,
> turned off the computer, and unplugged it. At this point any wall warts,
> modems, routers, etc were also  off. Still no significant changes.
> >
> > Take a look here at my spectrum, recorded while I turned off a breaker
> every 30 s. There is no difference between beginning and the end:
> https://1drv.ms/v/s!AiAwh4TnZjYMhtoFCHwTeJdHO2MFGw
> >
> > I really have not found any major decreases in hash or noise.  Here are
> my questions:
> >
> >    1.  Do I go right about this at all?  Should I only look at the ham
> bands instead of looking at the half the HF spectrum?
> >    2.  There is quite some pulsing/jumping of noise going on below 10
> Mhz (see in video’s top spectrum). Are those normal static atmospheric
> crashes or something else outside I should be investigating further and if
> so how?
> >    3.  There are patterns around 4 – 5 Mhz that are definitely some
> patterns from some device. Is it worth worrying about these, considering
> there are not near any ham bands of interest? Goes back to question 1 also:
> do I care whats outside of ham bands?
> >    4.  I have some harmonics, some spikes between 12 and 15 Mhz. the
> distance between the spikes is about 17.6khz. Any ideas what that could be?
> Is likely not in my house though…
> >
> > Any tips and ideas how to proceed?
> >
> > 73
> > Andy
> > KU7T
> >
> > Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
> >
> > _______________________________________________
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> >
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-- 

*Dave - WØLEV*
*Just Let Darwin Work*
*Just Think*
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