[RFI] CASE HISTORY - Powerline - Multiple Sources

Thu Sep 23 17:55:22 EDT 2021

On 9/23/21 12:04 PM, Charles Plunk wrote:
> Similar story here also with exception of pole change outs and 
> competent DF personnel (not sure of the current status of this as I 
> have done all my own df'ing fior years since the last horrible 
> experience with so called DF personnel........). Most of my issues 
> have been with the 2 poles in my front and back yard. I too had 
> numerous sources fixed eons ago by a then soon to retire competent DF 
> person. Since then its been like playing whack a mole. Fix one, a 
> period of some relief, another takes over.
>
> I am hesitant though to suggest pole change outs and have reason to 
> believe they would not do. It has been mentioned this can make things 
> worse for adjacent old poles moving all the hardware around. Maybe 
> better long term though. But wow, yes if they changed out the 13 close 
> poles to me that is a dream. I would settle for about 4 since most all 
> my 120hz RFI is on a 3 phase run and not the single phase or other poles.
>
> Some hope though. Last spring I contacted the utility, at least they 
> were talking a good game and came out quickly to fix one issue I 
> tracked down. Think it has to do with a new CEO and possibly 
> heightened awareness of the issue. I have 2 sources primarily now that 
> are intermittent with humidity and getting worse with the dryer 
> weather. When those 2 are absent though its down to very weak 120hz 
> and some weak junk coming from houses but very tolerable to me.
>
> On another note, I did get a new router in and some WIFI links. Going 
> to abandon my wired system and hopefully get rid of those birdies. 
> Should have a pile of toroids after that, lol.
>
> Chuck
> W4NBO
>
> On 9/23/21 11:23 AM, Michael Carter wrote:
>> Similar story here, but never had much doubt about
>> presence of multiple arc sources at different poles,
>> all within about 1/2 mile or less from my house, based
>> on my own DF'ing efforts.
>>
>> Bottom line: local electrical utility sent out very
>> competent RFI DF personnel, they independently confirmed
>> all of my offending arc source locations (more than 20!).
>> Although I certainly didn't request it, their report led to
>> replacement of 13 poles and all new hardware and transformers
>> on those poles.
>>
>> The unfortunate part: I still hear power line arc noise across
>> the HF range.  The search for more distant arc sources
>> continues.
>>
>> Mike, K8CN
>> Durham NH
>> ________________________________
>> From: RFI <rfi-bounces+mike.carter=unh.edu at contesting.com> on behalf 
>> of Alan Higbie <alan.higbie at gmail.com>
>> Sent: Thursday, September 23, 2021 12:06 PM
>> To: Rfi List <rfi at contesting.com>
>> Subject: [RFI] CASE HISTORY - Powerline - Multiple Sources
>>
>> CAUTION: This email originated from outside of the University System. 
>> Do not click links or open attachments unless you recognize the 
>> sender and know the content is safe.
>>
>>
>> Amongst the usual residential area microprocessor RFI trash,  I have 
>> also
>> endured powerline RFI at my station for years. I only operate on 160 
>> to 6
>> meters. Sometimes it gets worse - sometimes it subsides somewhat.  Wind,
>> moisture, and frequency dependent.
>>
>> I have kept an RFI log for at least the past 3 years.
>>
>> Despite my best efforts, finding the location of the source has been
>> difficult.  I didn't want to squander any goodwill with the power 
>> company
>> by having them come out before I had actually located the offending
>> pole(s).
>>
>> I had always assumed I had one RFI source.
>>
>> I have been using the National Radio HFDF loop with a Tecsun PL660
>> receiver. And, also I use an SDR (and the Tecsun) with a WD8DSB portable
>> flag. Also an FT817 on 440 MHz with 7 element yagi.
>>
>> Eventually, I noted very strong RFI that appeared to be coming from 
>> an area
>> of a chain-link fence that runs below and parallel to the powerline.  
>> I was
>> perplexed.
>>
>> Using my station's SteppIR I finally figured out that on 21 MHz the RFI
>> peaked in one direction (240 deg.) and on 28 MHz the RFI peaked in 
>> another
>> (105 deg.).
>>
>> So, that indicated at least 2 separate sources.  There is a power
>> pole (with a transformer) along each of those headings.
>>
>> But, I still wondered if this distinction was a result of 
>> re-radiation or
>> induced RFI.
>>
>> Eventually, I was awakened in the middle of the night by high winds.  
>> So I
>> came into the station, flipped on the receiver to note how the suspected
>> sources were acting.  At one point, the 21 MHz predominant source 
>> sputtered
>> off and the other (28 MHz) kept going. Then I knew for sure I had 2
>> separate sources!
>>
>> The next day I emailed our utility RFI guy.  I sent pole numbers, 
>> photos of
>> the hardware on the poles, an aerial map showing my beam headings to
>> their poles.  I asked him to come out. Within a few days he and another
>> engineer (who is a ham!) showed up with a troubleshooter-lineman and 
>> bucket
>> truck.
>>
>> I demonstrated the DF steps I had gone through (station receiver, beam
>> headings, how the RFI drops dramatically when the SteppIR is put into 
>> the
>> 180 reverse mode).
>>
>> We DF'ed again outside with the Tecsun and the VHF gear.  We walked 
>> to the
>> 1st pole (21 MHz source) and the lineman went up.  He inspected and
>> reported seeing significant deterioration on top of the transformer and
>> also track marks from arcing. As he poked around with the fiberglass hot
>> stick - the RFI sputtered and he eventually got it to stop (at least
>> temporarily).
>>
>> The utility guys had a Radar Engineers M 331 - but didn't use it today -
>> relying on my 440 MHz set-up instead.
>>
>> We repeated the process on the next pole down the line and then the 
>> next.
>>
>> During the visit, there was much discussion about the age of the
>> poles/hardware.  The subdivision dates to the late 1940's - so the
>> equipment might be 75 years old.  There has been at least one lightning
>> strike to one of the poles within the past 2 years.
>>
>> Well, after these sources were calmed down - listened some more - and 
>> still
>> had RFI coming from close to the same beam heading as one source we had
>> located.  I went hunting with the VHF gear.  I was able to confirm 
>> that the
>> next pole down the line was also generating significant RFI (which I was
>> still hearing on HF).  We had figured this was re-radiated or induced 
>> RFI -
>> - but it now turns out to be an independent source all on its own.  I 
>> have
>> supplemented my trouble ticket request and am told they will confirm
>> it, etc.
>>
>> Note: After the two sources on the poles were quieted down - the 
>> chain-link
>> fence RFI also went quiet.
>>
>> The good news: The utility advised yesterday that it will "replace 3 of
>> those poles and associated equipment" within the next 2 to 5 months.
>>
>> The bad news: Yesterday I saw my neighbor getting an estimate for a 
>> solar
>> system.
>>
>> 73, Alan K0AV
>> Colorado Springs
>>
>>
>>
>>
>>
>> and honing my DF skills - I finally determined that I actually have 3
>> separate sources of powerline RFI - on 3 separate poles in the alley 
>> up and
>> down behind my house.
>>
>> 2 days after we were poking around at your place - I was with Colo. 
>> Spgs.
>> electric utility guys last Friday doing precisely the same thing we 
>> did at
>> your place: engineer (also a ham!) + troubleshooter/lineman with a 
>> bucket
>> truck.  And, just like at your place, the lineman poked around the 
>> hardware
>> with a long fiberglass pole.  He located several particular places where
>> there was active arcing and which had track marks and deteriorated
>> insulation.  It was agreed that the RFI problems resulted from the 
>> age of
>> their equipment (60 years old) and perhaps lightning strikes.
>>
>> Bottom line: they emailed yesterday saying they will be completely
>> replacing 3 poles and their hardware in the next 2 to 4 months!
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