Johnny...
I have no experience with UHF quads, but I modeled, used and modified an
HF quad for over 15 years. I now use a SkyHawk HF triband yagi. Based on
that experience, quads require more mechanical effort for construction
and maintenance. The form factor for a yagi is two-dimensional, while
for a quad it is three-dimensional. Thus, packing, storage and transport
is potentially simpler for the yagi than for the quad. Feeding a yagi is
simpler than for a quad, because the yagi can use a solid driven
element, while the quad generally requires a break in the driven
element; this can complicate construction. Adding elements to a yagi
antenna is mechanically simpler than adding elements to a quad. So,
based on my HF experience - and thinking about UHF quads - I think
mechanical issues might be a significant difference. At UHF a 4/5
element yagi might be easier to deal with than a 3-el quad. My opinion.
...robert
On 4/4/2014 03:05, Johnny Siu wrote:
Hello Elecrafters,
It is off-topic and you can press 'DEL' now.
Hong Kong is quite a hilly place in the rural areas. Local ham
societies are often providing radio communication support services to
charity organisations having fun raising sports activities in these
areas. We have to set up UHF repeaters at the hill tops. Purely
from the radio text books, a 3 element quad gives better performance
than a 3 element yagi. However, I seldom see using directional Quad
in the UHF repeaters.
Apart from performance, are there any disdvantages (or advantages) of
using directional quad instead of yagi in UHF repeaters? Could you
share with me your experience in US?
Thanks for your help in advance and please reply off-the-list to
reduce the traffic in the mail listing (oh, yes, not forum!!)
73
Johnny VR2XMC
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Robert G Strickland, PhD ABPH - KE2WY
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Syracuse, New York, USA
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