[RFI] Signals on 160

Sun Oct 28 19:25:51 EDT 2018

After killing the power in your home, and if you find you are not the 
cause of your RFI, the best advice here is to build a loop...

They are mindlessly simple to build, and if you keep things neat, and 
orderly, and use a bit of ferrite material on the feedline you will get 
very, very, deep nulls...

Once you have the loop working, play with it a bit, get used to it, then 
take it for a spin looking for your RFI...

Take a bearing on the null, draw that bearing on a Google sat view of 
your local area.  Maybe a 15 block radius around your home.

Move a block and do it again, then move another block, and do it once 
more.  If all three lines cross close to each other, then your RFI is 
probably close to there...  If not, take more bearings, eventually you 
should see a pattern...

Listen in increasing frequency steps, as you approach, go up in 
frequency, and stay as high as you can and still hear the RFI.

Keep it below S8 on your receiver.  When you get really close, get a 2 
meter three element Yagi, and an aircraft receiver.  Why an aircraft 
receiver?  Because it does AM, and RFI really stands out in the AM mode...

Now take your three element Yagi, and use the skills you developed with 
the loop, and triangulate on the source again...  That will get you 
closer...  At some point you will know where the RFI is coming from...

At that point, I try and contact the person, (once I am dead sure), and 
in a nice, kind, non threatening way, bring up the fact that teh RFI is 
harming your reception.  I always have a second ham with me, and I never 
enter a residence... I let the person know he/she can kill the power, 
and I can tell them if the issue ends...

Most folks will work with you if you take that approach...  Don't 
threaten, don't tell them you will call the FCC on them, see if you can 
resolve it locally, in a friendly neighborly way...

But do take notes...  Very copious notes, of everything that happens, 
how you located the RFI, what it is harming for you, what was discussed, 
etc.   The FCC or the ARRL may at some point request your notes...  Keep 
them devoid of emotion, just the facts.

If you are having issues still, then call the ARRL Lab and ask for Mike 
Gruber.

All of the above is assuming things are "normal" in locating your RFI, I 
have worked for weeks locating a single source in an area with 
underground wiring...  The ARRL has a very good book on RFI, get that book.

I am now working with the ARRL on an issue that the friendly approach 
did not work on...  The FCC is involved, and another ham contacted me a 
few days ago about his RFI, which turns out to be my RFI as well.

He is getting RFI at 20 over S9 on 40, and on every other band, I am 
getting RFI at 10 to 15 over S9, on 40, and some on most bands.

He is slightly closer to the source than I am.  He is loosing the 
ability to even use his radio...

I trust the ARRL will work this out, but RFI takes time...  I am coming 
up on a year now...  Buckle up, and expect it to take some time.

To answer your question-- it is probably a SMPS, (Switching Mode Power 
Supply), hopefully in your own home, where you can just trash it.

Hope this helps...

73s and thanks,
Dave (NK7Z/NNR0DC)
https://www.nk7z.net
ARRL Technical Specialist
ARRL Volunteer Examiner
ARRL OOC for Oregon

On 10/28/18 12:54 PM, Hare, Ed  W1RFI wrote:
> "What is it?" is the wrong question. If someone said that it is a model Z-123 Netstuff modem, that really wouldn't help much.  The real question is: "Where is it?" Finding the house or location where the noise is originating is what you will get to eventually, so start with that question.
> 
> Many noisy devices can sound similar, so if someone tells you that it is a Z-123, and it is really a lighting ballast instead, you will be on a wild-goose chase.
> 
> Ed, W1RFI
> 
> 
> ________________________________________
> From: RFI [rfi-bounces at contesting.com] on behalf of donovanf at starpower.net [donovanf at starpower.net]
> Sent: Sunday, October 28, 2018 3:04 PM
> To: rfi at contesting.com
> Subject: Re: [RFI] Signals on 160
> 
> Hi Gary,
> 
> 
> Of course, the first thing you should do is turn off all of the AC
> power -- including UPSs -- in your own home to determine if any
> of the RFI disappears.
> 
> 
> 
> I don't think anyone will be doing you a favor by helping you guess
> what these signals might be. By far the best way to determine what
> they are is to build -- or if necessary buy -- a simple small loop antenna.
> A loop antenna has a deep, narrow azimuth null off of each side of
> the antenna that allows to quickly identify the RFI source.
> 
> 
> Good luck!
> 
> 
> 73
> Frank
> W3LPL
> 
> ----- Original Message -----
> 
> From: "Gary Smith" <Gary at ka1j.com>
> To: rfi at contesting.com
> Sent: Sunday, October 28, 2018 5:31:51 PM
> Subject: [RFI] Signals on 160
> 
> I've been encountering some strong signals
> on 160 recently. I made some approximate
> guesses at the frequency using the P3
> markers to measure them. Here's the
> signals at 1:20PM local time with a center
> frequency of 1.848.67
> 
> The main signals are about 42 KHz apart.
> The lesser spikes in-between appear at
> somewhat regular intervals.
> 
> http://doctorgary.net/spikes-on-p3.jpg
> 
> Here's the measured values of the main
> signals
> 
> http://doctorgary.net/frequencies.jpg
> 
> 
> Any idea what might be the source of
> signals spaced like this?
> 
> 73,
> 
> Gary
> KA1J
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