[RFI] RFI Detector

MikeR nf4l at nf4l.com
Mon Oct 3 21:36:06 EDT 2005

Local FCC rep ???
Mike NF4L

Mike at RFI Services wrote:

>Very well put Frank. 
>Don't give up on the FCC though. Many times your local FCC rep. doesn't
>understand the FCC's responsibility. That should be hard to believe.
>Best wishes to all,
>Michael C Martin
>RFI Services
>6469 Old Solomon's Island Rd
>Tracey's Landing, MD 20779
>Tel 240-508-3760
>Nextel DC 164*21*29180
>Fax 410-257-4514
>Please visit:
>-----Original Message-----
>From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com] On
>Behalf Of Frank N. Haas
>Sent: Monday, October 03, 2005 6:15 PM
>To: rfi at contesting.com
>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
>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.
>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
>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
>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 
>7.	Keep good records. Log your interference occurrences. Patterns can
>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...
>Frank N. Haas KB4T
>RFI mailing list
>RFI at contesting.com
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>RFI at contesting.com

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