[RFI] RFI Detector?

Dave NØRQ n0rq-lists at sbcglobal.net
Tue Oct 4 15:05:29 EDT 2005

Thanks for the superb write-up, Frank.

I agree with everything that was said, but wanted to
add this note...  If the power company cannot or
will not fix their problems, the normal escalation
is not to contact the FCC or the PUC (or your
attorney), nor should it be to take down your

The ARRL has an agreement with the FCC to try to
handle the initial complaint.  (In fact, if you try to
complain directly to the FCC, they will simply
ship it over to the ARRL.)

If you have unresolved line noise problems, go here:

Read it, then read it again, then do the necessary
documentation and send it to the RFI desk at the
ARRL.  They WILL get on it, write a very good
letter to the power company, along with a bunch
of good information.  Then, if it is not resolved
in 60 or so days, you contact them again, and it
can be escalated to the FCC, at which point one
of those nice FCC Enforcement letters gets written.

I've had power line noise problems for over 2 years, and
have complained with very limited success... so I finally
went the ARRL RFI route.  I'm halfway through
the 60-day period, and so far, no contact from the
utility, and lots of noise still coming from a number
of poles.  I have no plans of giving up.

As Frank said, patience and politeness are mandatory.

(I use a Yaesu FT-50 HT with 2m and 70cm,
on mode AM, and a 3-element 2m handheld yagi
or 7-element 70cm handheld yagi from Arrow,
www.arrowantennas.com -- works great.)

- Dave N0RQ

----- Original Message ----- 
From: "Frank N. Haas" <kb4t at arrl.net>
To: <rfi at contesting.com>
Sent: Monday, October 03, 2005 17:15
Subject: Re: [RFI] RFI Detector?

> Fellow RFI'ers:
> I am a Communications Specialist and Interference Investigator for a large
> electric utility.
> The company provides me with very esoteric and expensive tools 
> specifically
> designed to locate "sparking" interference sources typically caused by 
> high
> voltages carried on our transmission and distribution facilities.
> When I visit a customer's home to investigate interference I always carry
> one tool with me: an Icom T-90a. The T90a is a remarkable radio that I 
> find
> useful for many different applications but it is particularly useful in
> tracking down interference sources.
> The T90a receives from .5 MHz to 2 GHz and has amazing sensitivity across
> the spectrum. Modes include AM, FM and Wide FM. The antenna that comes 
> with
> the unit is worse than a dummy load so I replaced it with an MFJ 15 inch
> dual band (2M/440) thin and highly flexible whip. The radio is very small.
> It fits in the palm of my hand nicely. The speaker produces loud clear 
> audio.
> Depending on the nature of the interference issue, I can start low in
> frequency (in the AM broadcast band) or listen on whatever frequency
> (including TV channels) about which the customer is reporting the problem.
> As needed I can move up the spectrum to suit my needs.
> True sparking interference can be heard well into the hundreds of MHz when
> you are very close to the source. Typically you can hear the interference
> at a low frequency from a distance and as your movement brings you closer,
> you can increase frequency. Increasing frequency is much like using an
> attenuator to reduce signal strength as you get closer and closer. When 
> you
> can hear the sparking interference at 300 to 500 MHz you are usually
> standing right under or next to the source.
> An increasing percentage of my "in-home" interference issues stem from
> poorly designed switching power supplies found within inexpensive consumer
> electronics like DVD/VCR combo units and the like. With my T90a, I can 
> walk
> around the customer's home and bring the flexible whip near the suspect
> item and listen to the signal increase. I ask the customer to unplug (not
> just turn off) the item and if the noise goes away, the customer is
> surprised but pleased. If unplugging does not stop the noise, we keep
> looking. If the source is in the customer's home, it's much easier to
> search with the small handheld and very flexible antenna. This process is
> successful 95% of the time for in-home issues. Rarely have I had to break
> out the directional antenna to locate a source indoors.
> In the recent past I have found the following causes of severe sparking
> type interference:
> Door bell transformer
> Switching power supply for an elevator
> Switching power supply in a PC
> Switching power supply in a DVD/VCR combo unit
> Switching power supply in a cell phone charger stand
> Sprinkler system timer/controller
> High voltage electric fence for cow pasture
> High voltage electric fence to keep dogs within lot
> Light dimmers
> Photocell inserts in exterior lighting fixtures
> In my line of work, my employer is guilty until I prove us innocent. In my
> experience, only about 50% of the interference sources I locate are power
> company related. I consistently find consumer electronic devices that 
> cause
> TVI and RFI.
> True power line related sources are most easily found using equipment
> designed for the purpose. The T90a listening in AM mode on ever increasing
> frequencies will do nicely but a directional antenna (typically a 3 to 5
> element UHF yagi) AND a switchable attenuator make the job MUCH easier. If
> you don't have the luxury of using a $5000 scope-equipped DC to light
> receiver or a $3000 receiver mounted directly to a yagi that listens to
> 300+ MHz in AM mode, try using a $249 T90a, a $35 homemade UHF yagi and a
> $40 simple 4 to 6 switch attenuator. I'm sure many of you can find less
> expensive solutions. Essentially any frequency agile, AM receiver with an
> antenna jack should work.
> OR....
> Call your power company and ask for an interference investigation. My
> employer does not charge customers for interference investigations...no
> matter how long it takes...even if the problem ends up being something in
> your home and not in any way related to the power lines. If the service is
> free, take advantage of it. Your request should at least imply that the
> power lines are causing interference to your equipment :-)
> As long as I have deviated from the equipment theme, may I digress a bit
> further?   Interference investigators come in a wide variety of
> effectiveness. Some are very skilled and highly motivated and care a great
> deal about your issue. Some are just the opposite. You have to take what
> you get. If you don't like it, there's little that can be done except
> perhaps to ask for another investigator.  You can usually tell very easily
> who is skilled and cares. Ideally, your investigator would be an active
> Amateur Radio Operator with an extensive background in RFI location.
> Important things to remember:
> 1. Always be polite. The service you get will be directly and inversely
> proportional to the pleasantness of your attitude.
> 2. Most power company investigators actually have other primary
> responsibilities. Interference investigation is only a small part of what
> they usually do.
> 3. Try not to tell the investigator how to do his job. If the investigator
> seems incompetent to you, remain friendly and courteous but when he leaves
> call customer service and request someone else.
> 4. Your patience will be tested. Be ready to wait. If the investigation
> reveals a power company problem, it can take weeks, even months for a
> repair crew to be dispatched to correct your problem. Interference
> investigations and their resolution provide no income so they tend to be
> assigned fairly low priority. Remember #1. Once you start behaving angrily
> or with impatience and a sour attitude, you will only aggravate the 
> problem
> and extend the delay. Being kind, polite and courteous in the face of
> enormous frustration requires immensely powerful self-control but it does
> pay dividends.
> 5. Know your options. If your state has a Public Service Commission or
> other power company regulating entity, learn how they can help you. Call
> them, visit their web site, read the law...do whatever it takes to learn
> and understand your options. Knowledge and a good attitude will get the
> problem solved as quickly as possible.
> 6. The FCC is not your friend. Don't waste your time calling the FCC about
> interference issues. Unless you are another governmental agency, public
> safety agency, congressman or senator, the FCC will do nothing to help you
> solve your interference issue. They will always refer you to someone else.
> Their actions re: BPL should clearly show you they care nothing about RF
> pollution.
> 7. Keep good records. Log your interference occurrences. Patterns can be
> very helpful in locating the source. If you call in the pro's, get names
> and phone numbers. Log their visits, phone calls and actions. If you need
> to call in reinforcements, good records grease the skids.
> I hope this note is of value to at least some of you. This note is
> something of a catharsis for me as I've wanted to say these things time 
> and
> again after reading various notes on this list. RF pollution is widespread
> and frustrating to hams everywhere. When those I QSO find out that I am an
> interference investigator, they often express the wish that I could come
> visit them and help resolve issues with which they must cope. I wish I
> could do that too but it's simply not practical or cost-effective. I
> believe most hams can solve their own interference issues if they are
> willing to employ readily available resources and use the simple tools and
> services described herein.
> Back to lurking mode...
> 73,
> Frank N. Haas KB4T
> Florida
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