In a message dated 04/18/06 18:17:18 Eastern Standard Time, wlfuqu00@uky.edu
writes:
That reminds me about an interesting incident with a MFJ antenna analyzer.
Our club had just put up an new 2 meter repeater antenna. They had made
some adjustments to it in one of the member's back yard with it on a short
mast. When they took it to the site and installed it the MFJ analyzer was
pegged indicating a very high SWR. They were at a loss as to what had gone
wrong with the antenna. After hearing about their problem I informed them
that there were some high power pager antennas only a few hundred feet
away. I suggested that they check it again with a real swr/power meter. The
problem was that the antenna was picking up the 150 MHz signals from the
near by paging transmitters, and since there was more power flow from the
antenna to the analyzer than the in the forward direction the analyzer
thought the was SWR greater than infinity to one.
73
Bill wa4lav
Yep. Sorta ditto here.
I'm the AEC for the county ARES/RACES group. I had put together a new fan
dipole (80m/60m/40m) for installation at the Government Services bunker, but I
wanted to give it a pre-test in the back yard. I hauled it up the extra
tower halyard, and lifted the ends into my trees. Fired up the MFJ-269 and
proceeded to take some measurements.
Very strange! The measurements kept jumping in random excursions of
variable amplitude.
Yeah, it was kinda cloudy. And rain had been predicted to be arriving soon.
But the amplitude of the jumps seemed to be increasing. Increasing to the
point of concern. Bad coax? Wet coax? Tree branches touching? And then the
rumbles starting to roll in.
As the spikes started to peg the meter, I figured it was kinda prudent to
terminate the test, strike the halyard, lay the antenna to the ground, and get
my butt inside (just before the sky opened up.
The MFJ makes a wonderful RF field sniffer.
Unca Billy
N3TR
Chester County (PA) A/R AEC
PS --- The fan is still going gang-busterz. Required no retuning when
strung from the rooftop tower over to the main comm tower. Operates
wonderfully @
the design and harmonic freqs.
Better public service auxiliary comms thru fine ham engineering. HIHI.
;-))
Sidenote: Consider fans for efficiency and quick QSY. No trap losses. No
relays. No manual switches to forget to throw. HIHI.
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