I went through quite a bit of debate trying to decide which type of
antenna would crown my tower. I can't directly address the original question
about ice survivability with my own experience. Others have already
addressed the ins and outs of gain and pattern in this popular thread, which
resurfaces from time-to-time. I think the subject that really separates the
two antennas is maintenance and reliability.
It was very tempting to have 5 optimized bands (or more) in one antenna with
a boomless quad. These have proportional spacing, and you can nest VHF/UHF
quads inside. I have a friend who has a homebrew boomless HF quad on a 40
foot tower with a hazer. Although it does work quite well, he does have to
service it regularly, and a BAD ice storm here in southeast Virginia in Dec
'98 snapped two of his spreaders, while no local yagi owners lost elements.
I think the best made quads, in terms of reputation for surviving icing are
those from Max Gain Systems. The best performers also have separate feeds
for each band, requiring an antenna switch, thus more complexity.
It would be much harder to climb up and service a quad than a yagi. Another
consideration is that I sidemounted some vertical antennas on my tower. The
bottom ends of the quad elements would have interfered with the tops of the
verticals causing pattern interaction, and forcing me to install the
verticals lower. There are many more points to service with a quad than,
say, a trapless multiband yagi. The more complexity, the more the
maintenance.
I chose the Force 12 C-3E trapless yagi with the stainless steel hardware
option. It gives 5 bands (12 & 17 not optimized, but useable, with a tuner)
with the simplest design mechanically, smallest windload area, and extremely
light, compared to a quad of similar *survivability*. It was very easy to
install, using a tram line. It has a single feed point, using a choke coil
balun, for a minimum number of parts and connections. I think the design of
the F-12 antennas in general also balances the windload torque on the mast
to a minimum, reducing stresses on the rotor in a storm. These issues, not
advantages in patterns or gain, are what made the comparison no contest for
me.
Good luck!
--...MARK_N1LO...--
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