[RFI] Signals on 160

[Cortland Richmond]

Ed will remember the AT&T  modems on 80 meters.

I had good luck tracking them down in Petaluma and locating each one to 
specific rooms in a development of single-story duplexes.

It was Super Bowl Sunday and when people sharing cable co. services saw 
someone with antennas on his car and a "sniffer" (AOR 8000 with an 
untuned loop) they were running behind their houses to remove the 
illegal taps.

A 3-6 inch loop of rigid or even fairly stiff coax can be directive 
enough to find these harmonics and then at lower frequencies march right 
up to the source. H-field coupling drops off VERY fast away from a 
radiating conductor.

Cortland
KA5S


On 10/28/18 3:54 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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