I like what I hard you say in one of your classes, Mike, and that was advice to
the repair people to use an ultrasonic sniffer when they got up into the bucket
truck, to verify that they can hear the noise ultrasonically. If they can't,
it's the wrong pole.
We don't usually recommend to hams that they use ultrasonic equipment. First,
the inexpensive products available to hams are not sensitive enough to really
rely on them. Second, it does take some skill and practice, and one can be
misled by both corona and by the fact that sometimes, things lika sparking on
the top of an insulator can be blocked by the insulator so not seen from ground
level. If a ham can find the pole, his job is pretty much done.
But utlitiy personnel should use it, because they can closer and use it to
pinpoint an exact source.
Ed
From: RFI <rfi-bounces@contesting.com> on behalf of Michael Martin
<mike@rfiservices.com>
Sent: Thursday, December 12, 2019 10:50 AM
To: Wes Stewart <n7ws@yahoo.com>
Cc: rfi@contesting.com <rfi@contesting.com>
Subject: Re: [RFI] RFI Digest, Vol 203, Issue 15
Everyone has their own opinion,
So here's mine!
I use ultrasound on almost a daily basis. Usually when people have a difficult
time utilizing a source on a pole it's because they're on the wrong Pole. using
RF to locate the source is highly recommended and a must.
Also keep in mind that ultrasound units such as the mfj is very insensitive but
using an ultrasound device such as the radar engineers model 251, Which has
probably three times the sensitivity level of the mfj, can produce very good
results. Again it's only as good as the previous step so if you haven't
verified that the structure you're looking at contains the source you may not
be at the source structure there for the results will be poor with the next
step. I use ultrasound with about a 95% success rate. Even when I cannot
determine the source when using the ultrasound, I can usually determine what it
is because the ultrasound doesn't work.
As for the union issue, I've seen a couple of inputs concerning that and the
fact is there are Union rules and regulations that limit who can do this, not
just a safety standard. Unions determine, in a lot of companies, who can do
what job and high voltage is an area where they often regulate. The hot stick
line sniffer that is used on the end of a hot stick is extremely functional and
100% successful. The hotstick line sniffer has an RF detector that works at 114
megahertz as well as ultrasound that is 43 kilohertz. Both work well but may
only be used by people qualified to work in the primary zone or within the
minimum approach distance.
K3RFI
On Dec 10, 2019, 6:22 PM, at 6:22 PM, Wes Stewart via RFI <rfi@contesting.com>
wrote:
>I'm friendly with the RFI sleuth with our local electric coop (also a
>ham). He tells me that ground level ultrasonic sniffers are pretty
>worthless. Any physical obstruction attenuates the signal, according
>to him. They do use one but on a hot stick where it can sniff up
>close. Unfortunately, it's a union shop so he can't do it and has to
>have a line crewman do it. The logistics of this are really
>detrimental to efficiency. (Unspoken opinion of unions goes
>here.......................................)
>Wes N7WS
>
>
>
>Date: Tue, 10 Dec 2019 17:47:18 +0000
>From: David Eckhardt <davearea51a@gmail.com>
>To: Rfi List <rfi@contesting.com>
>Cc: "Bascombe J. Wilson" <jay.wilson@vodec.net>, Terry Bullett
> <tbullett@skybeam.com>, Ted C <hm55555@hotmail.com>, Greg Ella
> <gregella53@gmail.com>
>Subject: [RFI] ULTRASONICS for RFI SLEUTHING
>Message-ID:
>
><CAODdWWEESYCOMeuRLNXZh2M3_9Bj=xtA=Ypsn4Q7YKmJqhO1KQ@mail.gmail.com>
>Content-Type: text/plain; charset="UTF-8"
>
>Use of an ultrasonic detector is highly useful in finding discharges on
>the
>electric distribution grid, especially localized to the home
>neighborhood.
>Sure, MFJ makes one, but there is an option I ran across on the AirSpy
>group. if you have a Discovery (or R3 modified HF+) from AirSpy, you
>have
>an ultrasonic receiver. Have a view of the following link:
>
> https://youtu.be/H8z02pICisM
>
>--
>Dave - W?LEV
>************************************
>
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