As others have correctly stated, it is an OWA style design so it is closer
to a 3 element on 76 feet, which is a bit short still, but in in the 9 1/2
years that it has been up, it has been a good performer. At 53 deg north
(and way too close to the north magnetic pole) I need that much aluminum to
keep up with guys with low dipoles just a few hundred km south! Some of the
time, anyway.
When the beam was built in the summer of 1998, weight was a big concern as
the antenna would be installed "manually" with a winch line and gin pole,
and leapfrogging the guys, to get it to the 160' level. So at an estimated
1300 lbs, this was plenty to handle in this fashion. A longer boom would
have added more weight than I was equipped to handle at that time.
Plans are under way for a 5 el OWA design on 100 feet of Rohn 80 boom. The
boom is bolted together and weighed in at 1900 pounds. A finished target
weight of 5000 lbs or less is the goal, the capacity of the crane that will
be used to lift it to the 150 foot level. Progress has been slow, most of
the raw materials are on hand, the tower anchors are in, but many hours are
needed to put it all together. And summers are too short up here.
Don
VE6JY
On Sat, Mar 29, 2008 at 9:25 PM, Richard (Rick) Karlquist <
richard@karlquist.com> wrote:
> The boom on this is only 76 feet. That would be
> 19 feet on 20 meters. This seems way too short
> to justify 4 elements. In fact you can do pretty
> well with 3 elements up to a 26 ft boom on 20m.
> IMHO, the "full size" moniker applies only to the
> elements, not the boom.
>
> Rick N6RK
>
> Rob wrote:
> > ... and then there is the 4 element full size 80m yagi.... (+ others
> > on the website).
> >
> > http://alfaradio.ca/users/ve6jy/ve6jy-80m.html
> >
> > Rob
> > VE6TR
> >
> >
>
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