On Oct 9, 2007, at 9:56 AM, ku8e at bellsouth.net wrote:
> We have a 90 foot tower that holds the 40 meter yagi and a C3 above
> it. The tower has a pully
> system on it with a tram line. ... We can now use the tram system
> to support some other type
> of antenna.
>
> There is presently a 80 meter dipole at around 60 ft that is
> broadside towards the USA. It works fine
> for working W/VE along with our beverage. What I would like to do
> is maybe have some type of
> directional antenna pointed towards EU that could maybe be switched
> to the Pacific when the band dies
> to EU.
It may be tough to do something really sophisticated with a single 90
foot support.
How about a group of slopers? 90 feet is plenty high to support 1/4
wave and pretty close for 1/2 wave slopers. Seems like you could put
together a half-size version of the K3LR 160m sloper array:
http://www.arrl.org/members-only/tis/info/pdf/9408036.pdf (ARRL
members only)
How about a bi-directional SCV (Self-contained, Vertically-polarized
wire antennas):
http://www.cebik.com/scv/scv0.html
> I was scouring thru the ON4UN antenna book this weekend looking
> for ideas. I was thinking of maybe trying some type of phased wire
> vertical system. Phased verticals spaces 1/4 wl apart and with a
> 135 degree delay line you can get about 4.5db gain endfire. I also
> saw a diagram for a wire vertical with
> a sloping refector and director. The reflector had a loading coil
> with an Xl of 65 ohms on it. The director
> was grounded. I was also thinking about some phased delta loop
> system. I would like to try a quad but I think the tower is not
> tall enough.
I'd agree with you there.
You might think of using the central 90 foot tower to support a 4-
square (or may be just half a 4-square). 80m verticals are less than
70 feet tall. The phased verticals are an interesting idea. You could
drop them down from guy or support halyard.
One element of the K3LR sloper array would probably be the easiest to
arrange -- no tower climbing, no phasing lines, just hook it on from
the ground, pull it up and tie it off.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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