I think it's fair to point out that Sam's inquiry did not mention that
he doesn't have equipment and isn't mobile enough to chase after
something. Thus it's a bit unfair to get one's feathers all puffed up
when these important facts were not included in the original post. I'm
in no way clairvoyant. I would bet most of the folks on this list are
not either.
It's a bit disconcerting especially when one's intent is to share
useful info. It is absolutely amazing to me how seemingly simple
messages can have so many interpretations, good and bad. So, for the
record, my intent was not to be critical. My intent was to point out
that the most important fact one needs when resolving an RFI problem
is where it's coming from. I suspect Mike's "Well said." was meant to
compliment the author of the commentary rather than a slap at the
originator of the thread. I hope we can move on and stay focused on
the RFI parts and not the interpretation parts. This is not a
psychological forum. It's an RFI focused forum so back to topic...
Sam asked what something sounded like. A fair question. An exercise
that many seem to find at least entertaining if not useful. I, for
one, do not find that exercise of much value. I accept that having the
"signature" of an interfering signal can be useful but I rarely ever
need that info. I am able to locate 99% of the interference sources I
pursue without ever even seeing the signature. In fact, I only use my
Radar Engineers Model 242 (the receiver with the nifty LCD display and
display memories) only when I'm chasing an HF only source.
In fact, I have found some pesky carriers, buzzes, wheezes, burps and
so on with just a simple Eton E5 and a quick walk around the nearest
few houses. The E5 is an AM/FM/SW handheld that offers only a speaker
and a stingy signal strength meter.
The vast majority of interference sources I locate are within a 1/4
mile of the affected party. Only rarely do I find sources that are
farther away than a 1/2 mile. The argument can be made that multiple
power line sources can exist in a given area and finding THE source
among several requires a snapshot of the specific offender. Those
situations are EXTREMELY rare in my experience. In fact, I can usually
sort out multiple power line sources simply by paying attention to
what direction the DF equipment says the signals are coming from. If
the DF gear points to multiple buzzing sources I know I have more than
one place to look.
The RADAR ENGINEERS ad is not misleading. There are a great many
people who want very much to be precise and have detailed data about
their searches. I'm not one of them. It's not necessary for most of my
work. Having a snapshot of the signature is nice but is often of
little value to me. I don't need that information to locate the vast
majority of sources I chase. Most hams don't need signature info
either. Ask anyone who does bunny hunting how often they need the
signature of the signal they are chasing.
Admittedly I have an advantage over most. I do have the right
directional antennas and frequency-agile receivers to search on just
about any frequency. I realize that many people DO NOT have these
tools. I feel very strongly that local ham radio clubs need to begin
investing in these tools for the benefit of their ham radio community.
The spectrum is only getting more polluted. Hams are my most frequent
customers. Hams are among the most susceptible RFI victims. It only
makes sense to begin ramping up for the challenge. But this is another
topic entirely.
When I teach others how to DF, I am always amused by how often people
try to use their eyes instead of trusting their equipment. I believe
only superheroes can actually hear RF directly or perhaps see the
radio waves. Most of us mere mortals can neither see nor hear RF. So
we must use radio equipment as our eyes, ears and pointers.
Even if I could recognize the signature of an interference source
definitively without fail, that doesn't get me any CLOSER to resolving
my problem. Only by DFing the signal will I get CLOSER to it. Frankly,
I don't want to know what type of device I'm chasing until I actually
find it. I don't want my eyes and pre-conceived notions to get in the
way of my trust in my equipment. As someone else pointed out earlier
in this thread, you are no better off knowing what you are chasing and
can actually confuse the issue by assuming that your speculation is
accurate.
There are many ways to DF signals. I'm not sure this is the place to
get into that. Suffice to say, that knowing what type of device your
hunting isn't going to help you locate it.
I guess the bottom line here is equip yourself, or call upon your
peers or an expert, and start an objective DF effort to locate the
source. Then, over a couple of beers at lunch, you can laugh about the
$2000 Wobbulator 5000 that you just found that was blanketing the
spectrum with something that sounded just like power line
interference.
73,
Frank N. Haas KB4T
Utility Interference Investigator
Florida
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