I have been doing a lot of reading on methods to detect and resolve some of
these more difficult problems with powerline RFI.
There is an amazing amount of information and techniques that can be used that
goes beyond the typical methods that hams use.
Do a search on the subject of "partial discharge" There are many tools that can
be used to diagnose these poles and infrastructure.
For example, read some information from this company and others like Doble.
https://www.powermdt.com/partial-discharge
https://www.powermdt.com/sensor-technology
Companies like Doble and their PDS100
https://www.doble.com/product/pds100/
The technique of HFCT measurement could be used with a simple homebrew current
probe. However, I would be very cautious about fiddling around and connecting
things like a current probe around an arcing poles ground lead. I tried
simulating a similar ground lead discharge using a Fischer RF current probe and
current limited arcing source, and it seems to work. The same goes for a
capacitive probe that is nothing more than a high voltage coupling capacitor to
direct couple the noise.
The above-mentioned Doble PDS100 is a low resolution spectrum analyzer that
costs 20 thousand dollars. Something like the TinySa with a current probe and
preamp and bandpass filter for UHF detection could equally with. The
specifications on the PDS is worse than those early CATV cable TV and
Satellite TV spectrum analyzers. They are simply using the spectrum analyzer
with an an initial spectrum scan to establish the background noise floor then
they connect the sensors to establish if there is any partial discharge
activity. There are huge range of readily available scientifice and engineering
papers all freely available. The powerMDT web page has some good technical
information on the discharge characteristics of arcing and corona sources that
can help identify the sources of such emissions. Companies like Biddle also
sell a UHF PD spectrum analyser equipment. Even readily afordable spectrum
analyzers like the base model Rigol have better specifications than these PD
analyzers.
I just found some of this technical information on the techniques and
measurements very interesting. I am not an expert in the field. There is
certainly a lot more useful information on these companies web pages than you
will find from sources like Radar Engineers and the Loftness book.
73CraigVK3OD
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|