Fully support your views on the 5 band 2 element quad design Ken,
three years
ago I constructed a Gem quad for a friend back in the UK, added
elements for
12 and 17 metres and fed it with UR67 coax to an Ameritron remotely
controlled switch box on a 60 foot Versatower, then via individual 1/4
wave 75 ohm
matching stubs to the driven elements. Made the terminators for the
driven elements
out of Lexan and fitted PL259 plugs to them to take the 75 ohm stubs.
Very little
soldering involved apart from terminating the reflectors.
He rarely lifts it above the 40 foot mark but it will bust any pileup
on any band and
usually in less than 10 minutes. The only problem was the plastic ties
originally
used to fasten the elements to the spreaders failed too frequently, I
replaced them
with short lenghts of enamelled wire a year ago and we have,nt had a
break since,
the performance was unaffected. Front to back ratio, which can be
tricky on quads,
is excellent on all bands.
Another friend has the same antenna but fed with individual feed lines
for each band
which terminate in a manual coax switch in the shack, tower height is
only 40 foot
but the performance is equally outstanding. Sixteen contacts,
different bands and
modes, with VK0IR is testimony to that.
Bob G4LVQ now EA7/G4LVQ.
----- Original Message -----
From: <K7GCO@aol.com>
To: <Towertalk@contesting.com>
Sent: 28 October 1999 09:46
Subject: Re: R: [TowerTalk] Re: Welcome to towertalk
>
> Several has asked about a 5 band 2 element quad design with
individually
> driven elements using a coax switch at the tower. I actually added
6M also.
> I tested the design where the DE's are tied together.
> < In Eznec on 20, 18, 15, 12 & 10M I have 5 clean (improved)
patterns with a
> 5 band 2 element quad of tapered spacing and individual driven
elements. I
> even added 6M and you won't believe what happened to it. There is
very very
> little RF on the other off band DE's and reflectors.
> Not so with all DE's tied together which saves the customer
money but
> destroys the pattern. On 10M the free space vertical pattern is
tipped down
> about 35 degrees due to the unbalanced currents in the 18, 15 & 12M
DE. On
> 10M, the 20M DE has a high level of current in it as does the
reflector. I
> call CQ DX and DX stations call me from all directions around the
quad. Not
> so with individually driven elements. NOTE! So far every antenna
I've
> modeled in Eznec has checked out exactly for patterns good and bad
and even
> to the ohm. Putting a 6 band 2 element quad with tapered spacing in
a
> computer is a big job also.
--
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