Like most absolutes in life, this one is not absolute.There is a device which
you MUST track by itsnoise signature – the Sling Media Homeplug Ethernet
device. In Europe it is called PLT.
It uses a homeowner’s house wiring – and thewiring of every other home sharing
the commercial power distribution transformer – tobroadcast its ‘wifi’ signal.
A singleunit, in one home, will radiate from every foot of wiring in every home
on thesame transformer. DF’ing one with my National HFDF showed signal
–everywhere. There were peaks and nullsof course, but it originated from every
home and outbuilding with AC wiring. Since it is an HF signal and by design
has no VHF component,going higher in frequency to precisely resolve its
location is notpossible. You have to describe thedevice to the homeowner, and
then find it by a hard search. I have samples of its audio (RF) signatureif
you encounter this beast and want to shorten your time spent in locatingit.
Description: repetitive at approximately a 2 secondinterval. Fairly regular.
It sounds similar to an electric fence, butunlike electric fences, it is very
frequency specific. No RFI > 25 Mc. It is notched to avoid the amateur bands,
but blankets the 19meter and other higher and lower SW bands. Also there is no
component in the AM BCB. What my National HFDF unit did locate, was a pair of
arcingAC power connections in the attic of my neighbor’s home. We found the
Sling unit almost by accidentwhile killing breakers to repair the arcing
wiring.
I am not a professional RFI investigator. Just a poor dumb engineer.
ScottNM8R
On Tuesday, May 10, 2016 1:48 PM, Frank N. Haas KB4T
<utility.rfi.pro@gmail.com> wrote:
While extreme, the last example should be adequate proof that there is no
predicting how far RFI CAN or will travel.
I categorize this question in the same manner I categorize questions about
what a source might be by the recorded sound of the source. That is,
speculation about the nature of a source may be entertaining but it serves
no other useful purpose.
Each case is unique just like every other case. Time is best spent choosing
the best method for locating the source followed by actually locating the
source. Whether the source is 100 feet or 100 miles away, once it is found
all questions will be answered.
For the billionth time: RFI is not pinpointed with eyes or ears alone. Good
equipment ("tools") coupled with proper interpretation of the data provided
by the equipment will lead the investigator to the source. Guessing what a
source might be or how far away it might be is a fruitless waste of time.
It is my opinion that the primary message here should be: *Find it first.*
The answers will then be apparent.
Frank N. Haas KB4T
Utility RFI Investigator
Florida
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