In the vehicle I often like to use an old (i.e. analogue and inexpensive)
spectrum analyser like some of the portable Texscan CATV ones.
As CATV companies have transitioned from NTSC to QAM channel line-ups, high
quality field analysis meters have been showing up on the used market in big
numbers. I recently acquired a used Wavetek SAM III Digital for about USD
$100. Another great unit is the SAM I Analog.
http://www.ham-radio.com/k6sti/sam.htm
These units are excellent for localizing power line noise, especially when
used with a scope to replicate the noise finding method recommended by
Loftness and Radar Engineers. Dual AM and FM detectors, 480 MHz standard,
800 MHz optional, and tunes down to DC with lesser accuracy but fully
useable for noise search. It also has a rechargeable battery, super-rugged
field construction and a very high quality multi-step attenuator. A
significant feature over other FSMs is that with a scope, it functions as a
basic spectrum analyzer with reasonably good resolution bandwidth. Although
the S/A function won't help to localize power line noise, it's a handy
feature for secondary purposes. Not sure what these Wavetek units sold for
new, but I would not be surprised if they were in the $2K+ area.
Paul, W9AC
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Stew Perry Topband Distance Challenge coming on December 29th.
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