I spent the weekend putting in about a mile of radial wire in rocky
soil, so I have missed most of the fun here on the reflector, apparently...
Anyway, some of the poor performance by the Mosley PRO antennas in our
comparison tests was probably efficiency-related. I have to caution,
though, that the lack of a feed line choke balun (as directed by the
manual - part of our test protocol was to do/not-do what the manual said
to do/not-do) likely enabled coupling to the feed line shield. This can
distort the pattern tremendously, spraying RF all over and causing an
apparent lack of gain at low-angles, which is what we measured. Without
a full 3D measurement, I can't say for sure. It did not happen with the
other antennas for which a choke balun was specified and installed (a
bead balun or the manufacturer's own design).
The Mosley designs generally underperform for gain *somewhat* based on
equivalent boom lengths. The designs are decades old, so that is hardly
surprising. In the right location and height, they hold their own as
K4RO demonstrates on a regular basis. They are also quite sturdy
(heavy) if ice or wind is an issue to be considered. But they're not
dummy loads.
73, Ward N0AX
On 4/13/2015 9:15 AM, towertalk-request@contesting.com wrote:
The difference between Mosley and the other antennas is entirely
in antenna efficiency - not directivity.
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