Good Afternoon Randy,
Yesterday a 450mhz yagi portable directional antenna came in that I
ordered. 120hz arc RFI diminishes with frequency. Thus if you can hear
it at a higher frequency it makes more precise triangulation possible
once near the suspected source.
Prior to now I had primarily been doing my triangulation's at 145mhz and
below.
Today, I still am triangulating on the pole behind 637 Clifft Street and
at 450mhz this becomes very apparent. I get the strongest signal at the
top of the pole, no surprise there since that is the 7.2kv area. Since I
cannot hear it with ultrasonic, I am speculating that one of the
connections (transformer and lightning arrester) underneath the critter
guards is the cause, maybe loose. Or possible the insulator or lightning
arrester has a crack in it.
At any rate, thought I would update you on my findings. I surveyed all
the nearby poles and they are all quiet at 450mhz.
Its the pole behind the old wood shop building at 637 Clifft with jungle
like growth.
Thanks,
Chuck
One more note; After doing 4 triangulation's on different days, I still
center on the pole behind 637 Clifft Street. However, the next pole east
I get about 2/3's the strength readings. Poles either side of those 2
drops off drastically. So if nothing is found on the pole behind 637
Clifft, then please check the next one east.
Just wanted to add that.
Appreciate very much,
Chuck
On 10/7/21 7:03 PM, Charles Plunk wrote:
Good Evening Randy (or whomever is checking Randy's email while he is
away),
Thanks for the repairs today and finding the bad (cracked) disconnect.
I am encouraged that will solve the RFI on that pole. The young man I
spoke to was very courteous and confident he found the issue as well.
I will monitor it over time.
The RFI on the pole behind 637 Clifft Street remains though. Just
wanted to make sure you knew the disconnect did not fix this second
issue in case you need to do another request. I triangulated it
yesterday again for more than an hour, after I spoke to the crew,
using increasingly higher frequencies and still centered on this pole
behind 637 Clifft Street. Its just about got to be on the few pieces
of single phase hardware on the 7.2kv side of the transformer. A
instructor in RFI for Utilities advised this below;
-------------
Going by your notes, a single phase pole with nothing but a pole top
pin and a ground is probably one of two things.
Most common and most likely would be the staple and they shouldn't be
hammered in they should be removed and replaced so the new staple is
in fresh wood and will be tight for a long time.
The second source will be one of the bolts holding the pole top pin.
Commonly one is a through bolt that goes all the way through the pole
with a nut and washer on the backside and often the second one is a
lag which is no more than a very large wood screw that always comes
loose.
At any rate I would suggest they tighten both pole top pins and
replace the Staples maybe the first three or four from the top.
Sometimes hammering The staples in will work and sometimes only
temporarily. Other times not at all. /
/
It's unlikely to be a tie wire or the insulator unless it's been
struck by lightning which is a possibility and frequently you can tell
with binoculars that the top of the insulator is now White where the
coating has been burned off of it by the lightning. If it's insulated
conductor then that would be the most likely source that isn't
detectable with ultrasound (/Note; I could not hear it with
Ultrasound)/, because the arcing is through the rubber and on top of
the insulator where it can't be seen.
If it's a bare conductor and the tie wire is insulated then ask them
to remove about 4 inches of the insulation from the tie wire and twist
that end of the tie wire tightly on to the line and then that will
solve that problem. I'd love to see a picture of that pole standing
under the line looking straight up so you can see both sides of the pole.
At any rate these items will definitely cover that pole and you're
fortunate, if that is the source pole, to have such an easy pull to
resolve an issue on.
Best wishes and I look forward to hearing the result
-----------
Thanks,
Chuck
655 Clifft Street
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