[RFI] Noise - where do I start?

Mon Sep 26 06:57:03 EDT 2016

Ed,

Bravo!  

That is why I started with the recommendation that you cut the power to your own house first and run your radio on a battery as you bring up circuits one at a time to take measurements.  Taking detailed notes on the observations of signals both home, and eventually if you end up going around the neighborhood, is also key.

There have been a lot of other good suggestions, but doing the basics are essential for the reasons you provided.

73,

Gordon Beattie, W2TTT

201.314.694

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From:"Hare, Ed W1RFI" <w1rfi at arrl.org>
Date:Mon, Sep 26, 2016 at 3:29 AM
Subject:Re: [RFI] Noise - where do I start?

<Does the searcher have an open mind?>

I can't begin to say how important this is.  

ARRL staff hear all the time from hams about utility "investigations" in which the utility investigator did not set out to find the noise plaguing the ham, but begins the investigation with a goal of proving that the noise is not coming from utility equipment.  The investigator then finds a noise in a house a mile away and then concludes that the noise the ham hears is coming from that house, so the investigation is over.

We also hear from hams who before calling us have made up their minds that the noise they are hearing must be power-line noise, and so are not open-minded even about the process of beginning their investigation by turning off the power to their own house. We literally do have a case that involved years of working with the utility, only to find out in the end that the ham's noise was caused by a battery charger plugged in to an outlet in his own garage, long forgotten and running all that time.  Others are convinced that their noise is a "this" or a "that" and are barely able to consider any other possibility.

Ed Hare, W1RFI

________________________________________
From: RFI [rfi-bounces at contesting.com] on behalf of Frank N. Haas KB4T [utility.rfi.pro at gmail.com]
Sent: Sunday, September 25, 2016 10:17 PM
To: rfi at contesting.com
Subject: Re: [RFI] Noise - where do I start?

Questions of greater importance:

1.  Is the affected party equipped to do a search that will produce useful
results? A battery operated AM-FM-SW-VHF receiver with a useful signal
strength indicator and a directional antenna suitable for a walking search
that heats fairly well at the highest relevant frequency is essential. (My
personal choice is the Radar Engineers collection but for hams I recommend
the Tecsun PL660SLV available from Amazon or eBay for $85 to $150.)

2.  Does the searcher have an open mind? This kind of search is not an
eyeball search until the structure containing the source is located...and
even then, equipment must still be relied upon to pinpoint the source. By
open mind, I mean a willingness to trust the equipment and not waste time
guessing or deviating from the search path to pursue something seen or
guessed.

3.  Does the searcher know how to direction-find? The type of power
distribution facilities in the area is irrelevant at this point. Finding
the structure that contains the source is the only objective. Only by
trusting your equipment and using it correctly to lead you to the source
will the job get done with a minimum of wasted time and effort.

4.  Has the searcher done enough listening and record keeping to have a
good idea when the source is active, the best (highest?) frequency at which
to listen to hear and track the source and decide what tools are best to
locate the source? (Receiver, antenna, attenuator)

I do this for a living so for me time is money. Everything I do is done for
a good reason or I'm wasting time and money. Efficiency demands that every
part of the process have a useful purpose.

Hams and enthusiasts use these situations as learning experiences so extra
steps and experiments are often included. Lessons learned and experience
gained justify such steps. I still think that every step should be
evaluated to determine the value it will add to the process. At each point
along the way, the question that should be asked is, "How will this help me
pinpoint the source?" If a good answer can't be found, abandon that step or
option and move on to what will help.

Hunting interference need not be complicated. In fact it's a pretty simple
process. One located it can be complicated to correct or eliminate but
that's another subject entirely.

Stepping off my soapbox now.

73,

FranK N Haas KB4T
Utility Interference Investigator
Florida (on vacation in NC)
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