It may not even be a failed component, as any two pieces of poorly
bonded hardware can produce noise. That could explain the temperature
dependence. In any case, have them check all the hardware on that pole.
73,
Scott K9MA
(Who has had WAY too much experience tracking power line noise!)
On 1/28/2024 11:30 AM, Alan Higbie wrote:
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://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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Scott K9MA
k9ma@sdellington.us
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