On Thu, 10 Nov 2016 14:40:12 -0600, Jon Elson
wrote:
The OP is definitly in a weak area (45 miles from stations) and IS using an
aplifier just under the antenna.
Yep, and there's another problem:
http://802.11junk.com/jeffl/coverage/KBCZ-WBZ/WBZ-Lenny.jpg
That a really rough and crude guestimate of the path, which shows a
150ft pile of dirt blocking the signal. It could be knife edge
diffraction, but I don't think so. My guess(tm) is some part of his
system (antenna, amp, coax, splitter, power injector, TV) is broken.
Anybody within a few miles in the general
direction of the broadcast antenna could be trashing his signal.
Yep. I didn't check for other UHF TV stations in his area. Overload
(blocking) is possible, but usually affects ALL the channels. Since I
determined that the theoretical signal strength from both WBZ and KVCB
are almost identical, I don't see a nearby signal trashing one signal,
but not the other. The lack of complaints about other channels also
points to a specific problem on UHF channel 30.
Without
the proper equipment (portable spectrum analyzer), it could be quite hard to
find the problem.
Test equipment is always nice to have. However, I think this one can
be nailed by simply substituting parts of the puzzle and comparing the
effects on both WBZ and KBCZ. When something is replaced that makes
the signals equal, then the problem has been found.
However, if you really want to use a portable spectrum analyzer, any
of the RTL2832U SDR receiver dongles make a nifty spectrum analyzer.
http://www.rtl-sdr.com/?s=spectrum+analyzer
I run several RTL-SDR programs on my Google Nexus 7 tablet that acts
something like a spectrum analyzer.
https://play.google.com/store/apps/details?id=marto.androsdr2
The basic sensitivity of the typical USB SDR dongle sucks without an
RF preamp, but should be good enough to see what's arriving from the
antenna mounted amplifier.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558