Maybe I was not clear in my last post (although I did state it was from my
perspective. Maybe that is insufficient in this day and time.)
For starters, not knowing the type of antenna puts one at a disadvantage when
watching that first video where the op steps through the ham bands and observes
the noise at varying intensities as different bands are selected. I would also
like to add the antenna type to the video description.
Secondly, again, from my perspective, it would be nice to know the
*environment* in which these observations are made. No? We don't even know if
it is urban vs suburban vs out in the country (I have not checked the ops
location on Goggle maps, and it is possible the op is at an alternate location)
and whether the op has 3 phase 14 kV service running down the street out in
front of his property or whether he is in town and has buried utilities in the
back alley.
Why do I ask this? Because I have experience in tracking down noise in both
kinds of environments, and would like to access the proper experience or memory
'database' to get a better idea of the scenario we are dealing with 'on the
ground' in the op's area.
These are not unreasonable requests, nor are they in the vein of conjecture or
hypothesis or speculation. These are requests for factual information.
On the subject of actual DFing, much can be written. It can also be said that
most ppl, including some of the professionals are ill-equipped to DF much below
2 meters and especially on the lower ham bands like 80 and 160 meters. For DF
service on the lower frequency bands I have found some of the older marine
direction finders incorporating a sense antenna to be ideal for lower band DF
work. Imagine a hand-held receiver with a Cardioid antenna pattern and one gets
the idea.
In just the preceding 7 months I have DF'd and the power company has corrected
three different what I call in correspondence "wide-area" arcing noise sources
affecting, in particular, 160 meters with very little noticeable interference
on the other bands. These 'sources' were on the order of 1.5 to 5 miles away
and involved distribution lines. One of these adventures (the five mile away
source) I posted to the list back in about February or March with little
attendant fanfare.
The five-mile-away source was also discernible on the lower end of the LW
beacon band using the battery powered portable Marine DF receiver.
Regards,
Jim WB5WPA
From: Frank N. Haas KB4T <utility.rfi.pro@gmail.com>
To: rfi@contesting.com
Sent: Sunday, September 25, 2016 9:17 PM
Subject: Re: [RFI] Noise - where do I start?
Questions of greater importance:
1. Is the affected party equipped to do a search that will produce useful
results? A battery operated AM-FM-SW-VHF receiver with a useful signal
strength indicator and a directional antenna suitable for a walking search
that heats fairly well at the highest relevant frequency is essential. (My
personal choice is the Radar Engineers collection but for hams I recommend
the Tecsun PL660SLV available from Amazon or eBay for $85 to $150.)
2. Does the searcher have an open mind? This kind of search is not an
eyeball search until the structure containing the source is located...and
even then, equipment must still be relied upon to pinpoint the source. By
open mind, I mean a willingness to trust the equipment and not waste time
guessing or deviating from the search path to pursue something seen or
guessed.
3. Does the searcher know how to direction-find? The type of power
distribution facilities in the area is irrelevant at this point. Finding
the structure that contains the source is the only objective. Only by
trusting your equipment and using it correctly to lead you to the source
will the job get done with a minimum of wasted time and effort.
4. Has the searcher done enough listening and record keeping to have a
good idea when the source is active, the best (highest?) frequency at which
to listen to hear and track the source and decide what tools are best to
locate the source? (Receiver, antenna, attenuator)
I do this for a living so for me time is money. Everything I do is done for
a good reason or I'm wasting time and money. Efficiency demands that every
part of the process have a useful purpose.
Hams and enthusiasts use these situations as learning experiences so extra
steps and experiments are often included. Lessons learned and experience
gained justify such steps. I still think that every step should be
evaluated to determine the value it will add to the process. At each point
along the way, the question that should be asked is, "How will this help me
pinpoint the source?" If a good answer can't be found, abandon that step or
option and move on to what will help.
Hunting interference need not be complicated. In fact it's a pretty simple
process. One located it can be complicated to correct or eliminate but
that's another subject entirely.
Stepping off my soapbox now.
73,
FranK N Haas KB4T
Utility Interference Investigator
Florida (on vacation in NC)
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