If you don't want to shunt feed your tower, you don't want a sloper,
unless you mean a sloping dipole. But that isn't likely to be very good
either. To work the zones you listed, you need something to produce
good gain at low angles.
A beam made from inverted vees won't work very well at low height.
However if you can keep the ends at about 50 ft above ground it should
do pretty good. It will be a killer for stateside, but even for DX a 2
element version should outperform a single vertical in one direction.
This antenna takes up a LOT of space.
Phased verticals are a good choice, but are can be a lot of work putting
down radials. For DX purposes two phased verticals should be about the
same as the 2 element beam using vees, although the beam will kill the
verticals for close contacts.
Another antenna for consideration is the loop I described in another
post today. If your supports are in the right direction, a vertically
oriented loop fed with vertical polarization may be an option. A loop
with the top wire at 80 feet, with 102 ft horizontal wires and 42 ft
vertical wires will beat a single vertical in two directions. It will be
slightly better than that vee beam up to about 17 degrees elevation.
I don't know propagation from your location, but some of the zones you
mentioned are often better long path from where I am. That may be a
consideration.
Since this is a temporary antenna and you want to have it going in
November, I would suggest the simplest antenna to construct. You will
have to be the judge of that depending on what you have to work with.
You can't work them if you can't hear them. What do you have for
receiving? Got room for a beverage?
Jerry, K4SAV
Stone, Gary R. wrote:
>Greetings,
>
>
>
>Well, I am thinking of putting up a temporary (due to my situation)
>better antenna for 80 meters. I hope to do this for the end of November
>CW contest. I am trying to finish up some zones on 80 meters.
>
>
>
>What I have is an 80 foot tower (and I don't want to shunt feed the
>tower due to some other equip mounted on the tower and I would be afraid
>of frying the components - like my wireless Internet and I want it more
>temporary due to my landscape considerations).
>
>
>
>1- I am thinking about a half-wave wire sloper and if hung from the top
>of the tower I could get a pretty decent angle? (drawback here is my
>house is just about in the way of a good direction for most of the 80
>meter targets I need for my WAZ 80 meters - but this could be workable.
>
>
>
>2- I could sting up a temporary vertical wire with 40 or more radials
>laid on the ground. To do this I could string a rope from the top of
>the tower to a large tree and drop the vertical down from the rope?
>
>
>
>3- I could maybe make a 3 element wire V beam and again hang that from
>the rope between my tower and the tree?
>
>
>
>I am in Texas and several of the zones I need on 80 meters are in the
>same general direction (18,22,23, 24,26) so a 2 element could split the
>difference some. And I could use it one direction (toward pacific and
>asia) for half the contest and switch the reflector and director for
>pointing toward Europe and Africa for the rest?
>
>
>
>So, any input appreciated. Especially any experience with a wire
>vertical beam - or a wire V beam would be appreciated. Could I drop 3
>vertical elements (1/4 wave each) off the rope between the tree and the
>tower to get gain? Would they have to be three quarter waves (I would
>have only a max of about 70 feet with some expected droop from the rope
>off the 80 foot tower.
>
>
>
>Ideas appreciated.
>
>
>
>Gary, N5PHT
>
>
>
>
>
>
>
>_______________________________________________
>
>
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk@contesting.com
>http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|