[RFI] Source power pole located - but wonder which components most likely temperature sensitive

Sun Jan 28 17:02:44 EST 2024

In my case, the lightning shunt could not be located with the ultrasonic
microphone, but the guys noted discoloration of the large disc.  They'd
seen it many times before.

Dave - WØLEV

On Sun, Jan 28, 2024 at 8:10 PM Michael Carter <Mike.Carter at unh.edu> wrote:

> Thanks for mentioning the lightning shunts, Dave.
> I didn't see any on the pole Alan identified as
> the suspect one, but perhaps that's my eyesight.
>
> There is a capacitor bank on the left-side pole
> in Alan's photo, and it appears there may be lightning
> shunts on those taps for the capacitors.
>
> We rarely observe the failed/failing lightning
> shunt source of arcing here even though we
> do get lightning in the summer.  Jeff, W4DD
> has commented on the prevalence of those
> sources in the southeast U.S. (he's in Georgia)
> where he does his RFI sleuthing.  The behavior
> of those shunts is the opposite of what we
> see with tie wire arcs - the failing shunts arc
> more steadily in humid or actively precipitating
> weather.  Tie wire arcs go quiet when wet enough.
>
> 73,
> Mike, K8CN
> ------------------------------
> *From:* David Eckhardt <davearea51a at gmail.com>
> *Sent:* Sunday, January 28, 2024 2:59 PM
> *To:* Michael Carter <Mike.Carter at unh.edu>
> *Cc:* Alan Higbie <alan.higbie at gmail.com>; Rfi List <rfi at contesting.com>
> *Subject:* Re: [RFI] Source power pole located - but wonder which
> components most likely temperature sensitive
>
>
> 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.
>
> Don't neglect the standard lightning shunts on the poles.  My last case
> involved just those.  Once the power provider replaced a single lightning
> shunt, the RFI totally vanished.  They can and do become damaged by
> shunting multiple lower-level discharges, much like MOVs.
>
> Dave - WØLEV
>
> On Sun, Jan 28, 2024 at 7:40 PM Michael Carter via RFI <rfi at contesting.com>
> wrote:
>
> Hi Alan,
>
> I was intrigued by the 2-level primary distribution
> lines - not something we see here in New England.
>
> I wasn't able to zoom into the photo to see the
> detail of the insulator type.  Older bell insulators
> with tie wires have been a chronic problem in
> my neighborhood - the tie wires fracture and
> create perfect spark gaps.  The local utility has
> gone to using 'vise-top' insulators that eliminate
> tie wires altogether when they replace the bell
> insulators.
>
> The cessation of arc noise at moderate temperatures
> is curious.  The arc sources in my neighborhood
> have been sensitive to humidity and actual precipitation
> more than temperature.   Have you noticed any reduction
> of arc noise intensity when there is active precipitation at temperatures
> below 35F?
>
> Your local utility should acquire an ultrasonic dish
> locator - it's remarkable the pinpoint accuracy of
> this tool down to locating a hidden arc on a bolt/nut
> junction.
>
> Is there any change in RFI level after dark while
> temperature remains close to the end-of-day temperature?
> The presence of the street lamp on the suspect pole
> is the reason for the question.
>
> 73,
> Mike, K8CN
> ________________________________
> From: RFI <rfi-bounces+mike.carter=unh.edu at contesting.com> on behalf of
> Alan Higbie <alan.higbie at gmail.com>
> Sent: Sunday, January 28, 2024 12:30 PM
> To: Rfi List <rfi at contesting.com>
> Subject: [RFI] Source power pole located - but wonder which components
> most likely temperature sensitive
>
> [You don't often get email from alan.higbie at gmail.com. Learn why this is
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>
> CAUTION: This email originated from outside of the University System. Do
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>
>
> I have located the source of the power line RFI.
>
> The local utility RFI engineer (P.E.) has my RFI trouble ticket in the
> queue. Hopefully within the next week or so.
>
> But, now I'd like to gather ideas about WHICH COMPONENT(s) are the
> likeliest suspects - so I can be as helpful as possible when the
> utility guys show up.
>
> Otherwise they'll go up with hot stick and wiggle components - which is how
> they have located problem hardware in the past.
>
> Background:
>
>    1. This source produces approx. 30 dB increase in noise floor on 40
>    meters. Similar on other bands.
>    2. DF'ed: first with 40 meter beam; then with portable flag
>    unidirectional antenna; then zero'ed in with 440 mHz 7 element yagi.
>    Repeated process.
>    3. Important clue: The RFI is steadier (and stronger) with lower
>    temperatures. Example: absolutely horrible with outside air temp. of 0
>    degrees F.  But, more of spitting intermittent irregular approx. 1-3
>    impulses per second when temperature gets above 35 deg. F - and settles
>    down at 40-45 deg. F.  All under windless conditions.
>    4. I don't know enough about what hardware components on pole would be
>    most likely to be temperature sensitive.
>
> This reflector does not allow attachments.
>
> So, I have temporarily uploaded a PHOTO to my QRZ.com page
>
> https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.qrz.com%2Fdb%2FK0AV&data=05%7C02%7Cmike.carter%40unh.edu%7C44ee17d476c548d0384d08dc2026dd46%7Cd6241893512d46dc8d2bbe47e25f5666%7C0%7C0%7C638420598501112815%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata=kCN2N4c78lQnb1b18N9OxFqqRbQ0zmOW6oxF%2F6K07QY%3D&reserved=0
> <https://www.qrz.com/db/K0AV><https://www.qrz.com/db/K0AV>
>
> *Note:* The RFI is coming from the pole on the *RIGHT - NOT the one on the
> left.*
>
> Thanks for ideas.
>
> 73, Alan K0AV
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> --
>
> *Dave - WØLEV *
>
>
>

-- 

*Dave - WØLEV*