[TowerTalk] Re: Yagi's

[K3BU@aol.com]

Received from Art, KB9MZ, which he doesn't mind to share with the group:

>>Hi Yuri
I, like Joe W1JR are getting a lot of enquires on what is the "best' antenna
regarding the recent posts and I am sure you get the same with Rasors
And it appears that even the most seasoned of amateurs just focus on GAIN,
F/B and SWR which is really a very unwise and immature aproach.

GAIN alone sounds very good but what could come along with it?
High gain can come with baggage such as a narrow bandwidth  that
when pointing at Europe the main lobe is not all encompassing but is
so sharp that it requires constant adjustment thus more compatable with 
moon work instead of Dxing.
FRONT TO BACK alone sounds very good also but the figure is useless until one 
views the antenna patterns across the band. In some cases a F/B can 
appear lousy but if one looked at the antenna pattern one might well see
a very narrow lobe that is exactly at the rear but sip, really clean, for
 the rest of the rear 180 degrees and ofcourse the reverse can happen for 
the best of F/B claims which have large lobes to the side and perhaps
 more at the front. At the same time excellent F/B can be very damaging
if your main use is chatting on the nets where you want to hear everybody

SWR can also be misused an awful lot by the inbuilt "matching' system
whether it be capacitor matching method or the use of a folded dipole e.t.c.
but these really could  amount to nothing but a 'fad' .
 If one uses the low loss lines that are available today 
whether it be ladder line or hard line the actual SWR can be
inconsequential in terms of losses. by the same token a very
 good SWR can also hide a very poor antenna

So really no decision can be made without determining it,s end use
and what is required of it  and I am reminded at this time a former 
poll showed that contesters had little interest in F/B!
So there is no real answer or super antenna just a question
of pattern and end use but one MUST always pay attention to the
pattern and how much it varies from the most desired 'spot' 
statistics presented
Art KB9MZ
<<


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