[TowerTalk] antenna choices for K4XS

[Ward Silver]

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 at contesting.com wrote:
> The difference between Mosley and the other antennas is entirely
> in antenna efficiency - not directivity.