On 12/17/2013 4:45 PM, Jeff Liebermann wrote:
On Tue, 17 Dec 2013 07:42:01 -0500, Jerry Stuckle
wrote:

Actually, if you have the right equipment, you can narrow it down in a
very short time.

What is the right equipment? A portable spectrum analyzer is not in
my budget and my bench test equipment is too heavy for sniffing in the
field. I'm fairly well equipped for 2.4GHz wi-fi interference, but
not for HF.


Most cable-related problems will show up on a certification tester such
as the Fluke DTX CableAnalyzer (the one we use). Others can be isolated
with a spectrum analyzer in conjunction with a (actually, several)
directional antenna(s). Portable spectrum analyzers are pretty easy to
carry around.

If you're in this as a business, both of the above are a necessity for
proper installation.

It seldom takes us more than an hour to find RFI
problems, and most can be done in 10-15 minutes. It never takes us
days, even in large installations.

Impressive. I assume those are continuously generating RFI sources,
not sources that appear intermittently or drift all over the place as
they warm up. I spent about a month chasing down a noise source that
turned out to be the 24v battery charger on a diesel generator. Some
grid tied solar controllers seem to be problems and take some time to
find because they can be miles away. Fortunately, they're usually
easily fixed with the manufacturers optional filter kit. It took me
about a week to determine that my weather station was the source of
some 20 meter trash. The problem was that it only generated noise
when running on the internal backup battery, and not on AC power. The
ones that disappear when the AC power is temporarily turned off are
usually quite easy. The one's that don't take me much longer to find.



Not at all impressive. We have the right equipment to locate problems.
But then our customers don't expect us to chase down 24v battery
chargers on diesel generators. We chase down stuff in our equipment; if
it isn't our stuff we will track it down for them - but we charge by the
hour (and it's a rather hefty charge).

--
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Jerry Stuckle
JDS Computer Training Corp.

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