I have seen many plots of inverted V and flat top dipoles, but none of a
V or U shaped one.

That is like one I have up for 80 meters. I have two trees that are
about 20 feet short of the distance I need for an 80 meter dipole. The
trees are so that I can get the wire up about 60 to 70 feet on the ends
and the middle is only about 35 to 40 feet above ground. As I don't
plan on digging up and moving the tree, I just have to take what I can
get for that antenna. I know it would be nice to have the middle up
higher as that is where most of the radiation is suspose to come from.

Are there any web sites that may have one of those types of antennas
already ploted ?


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Ralph Mowery wrote:

I have seen many plots of inverted V and flat top dipoles, but none of a
V or U shaped one.

That is like one I have up for 80 meters. I have two trees that are
about 20 feet short of the distance I need for an 80 meter dipole. The
trees are so that I can get the wire up about 60 to 70 feet on the ends
and the middle is only about 35 to 40 feet above ground. As I don't
plan on digging up and moving the tree, I just have to take what I can
get for that antenna. I know it would be nice to have the middle up
higher as that is where most of the radiation is suspose to come from.

Are there any web sites that may have one of those types of antennas
already ploted ?


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The free demo version of EZNEC will do it.


--
Jim Pennino

On 8/31/2016 10:10 AM, Ralph Mowery wrote:

I have seen many plots of inverted V and flat top dipoles, but none of a
V or U shaped one.

That is like one I have up for 80 meters. I have two trees that are
about 20 feet short of the distance I need for an 80 meter dipole. The
trees are so that I can get the wire up about 60 to 70 feet on the ends
and the middle is only about 35 to 40 feet above ground. As I don't
plan on digging up and moving the tree, I just have to take what I can
get for that antenna. I know it would be nice to have the middle up
higher as that is where most of the radiation is suspose to come from.

Are there any web sites that may have one of those types of antennas
already ploted ?

Yeah. Search for V antenna on the Web. A V antenna has some gain
pointing approximately away from the apex. Your description indicates
that you might warm the clouds. Jimp's suggestion is a good one.

In article , says...


Yeah. Search for V antenna on the Web. A V antenna has some gain
pointing approximately away from the apex. Your description indicates
that you might warm the clouds. Jimp's suggestion is a good one.

I know about th emodling programs and have played with a few that
already have the elements in them. Just have not seen one for the U
shaped one like I have. I am not too familiar on how to enter elements
that are not streight. Come to think of it, I guess I could enter it
just as a V shape like the inverted V antennas are.

The V antennas that have gain I am thinking of are usully horizontal
and several wavelengths long.




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Ralph Mowery wrote:
In article , says...


Yeah. Search for V antenna on the Web. A V antenna has some gain
pointing approximately away from the apex. Your description indicates
that you might warm the clouds. Jimp's suggestion is a good one.

I know about th emodling programs and have played with a few that
already have the elements in them. Just have not seen one for the U
shaped one like I have. I am not too familiar on how to enter elements
that are not streight. Come to think of it, I guess I could enter it
just as a V shape like the inverted V antennas are.

The V antennas that have gain I am thinking of are usully horizontal
and several wavelengths long.




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A dipole with no support in the middle and the weight of the cable will
be close enough to straight for all practicle purpose.

If you support in the middle, the wire on each side will take the shape
of a Catenary. See: https://en.wikipedia.org/wiki/Catenary

You can, from the above, plot what the shape will be and approximate
with two or three straight lines for either side.


--
Jim Pennino

On 8/31/2016 1:46 PM, Ralph Mowery wrote:
In article , says...


Yeah. Search for V antenna on the Web. A V antenna has some gain
pointing approximately away from the apex. Your description indicates
that you might warm the clouds. Jimp's suggestion is a good one.

I know about th emodling programs and have played with a few that
already have the elements in them. Just have not seen one for the U
shaped one like I have. I am not too familiar on how to enter elements
that are not streight. Come to think of it, I guess I could enter it
just as a V shape like the inverted V antennas are.

The V antennas that have gain I am thinking of are usully horizontal
and several wavelengths long.

What jimp said plus EZNEC can model a catenary. I've not used it, but
it's there.

Ralph Mowery wrote:

I have seen many plots of inverted V and flat top dipoles, but none of a
V or U shaped one.

That is like one I have up for 80 meters. I have two trees that are
about 20 feet short of the distance I need for an 80 meter dipole. The
trees are so that I can get the wire up about 60 to 70 feet on the ends
and the middle is only about 35 to 40 feet above ground. As I don't
plan on digging up and moving the tree, I just have to take what I can
get for that antenna. I know it would be nice to have the middle up
higher as that is where most of the radiation is suspose to come from.

Are there any web sites that may have one of those types of antennas
already ploted ?


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One other thought, a trap dipole is physically shorter and you get
multiple bands.

According to the Reyco trap charts, the total lengths a

30/80 ~117 feet
40/80 ~113 feet
30/40/80 ~106 feet

Or you can go single band and inductively load each leg.


--
Jim Pennino

On Wednesday, August 31, 2016 at 11:01:09 AM UTC-6, wrote:
Ralph Mowery wrote:

I have seen many plots of inverted V and flat top dipoles, but none of a
V or U shaped one.

That is like one I have up for 80 meters. I have two trees that are
about 20 feet short of the distance I need for an 80 meter dipole. The
trees are so that I can get the wire up about 60 to 70 feet on the ends
and the middle is only about 35 to 40 feet above ground. As I don't
plan on digging up and moving the tree, I just have to take what I can
get for that antenna. I know it would be nice to have the middle up
higher as that is where most of the radiation is suspose to come from.

Are there any web sites that may have one of those types of antennas
already ploted ?


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One other thought, a trap dipole is physically shorter and you get
multiple bands.

According to the Reyco trap charts, the total lengths a

30/80 ~117 feet
40/80 ~113 feet
30/40/80 ~106 feet

Or you can go single band and inductively load each leg.


--
Jim Pennino

All you lose is bandwidth although you can always adjust it for your
favorite areas of the bands you operate on.
Irv VE6BP

In article ,
Ralph Mowery wrote:

I have seen many plots of inverted V and flat top dipoles, but none of a
V or U shaped one.

That is like one I have up for 80 meters. I have two trees that are
about 20 feet short of the distance I need for an 80 meter dipole. The
trees are so that I can get the wire up about 60 to 70 feet on the ends
and the middle is only about 35 to 40 feet above ground.


Here's a different suggestion. Put up as long a section (horizontal
except for the sag) as you can between the two trees. Say you can get
115 ft that way. Then extend each end 10 ft by adding a vertical wire
dropping down. Now the high current point on 80 m is way up in the air
where it will do the most good and the antenna won't be as much of a
cloud-warmer as your non-inverted V would have been.

Yet another suggestion: Just put what you can up there between the two
trees. So it's 20 ft or so short. Feed it with home-made open wire
(second choice: ladder-line). Use a good tuner. The main problem with
antennas slightly short of a half-wave long is that they have relatively
low resistance and appreciable capacitive reactance so feedline losses
go up. But if you use really low loss feedline they can still be pretty
good. For use on harmonics there is some advantage to avoiding an actual
half-wave on 80 m since that will have very high impedance on even
harmonics and with some feedline lengths can be very hard to match.

David VE7EZM and AF7BZ

--
David Ryeburn

To send e-mail, change "netz" to "net"

In article david_ryeburn-9073AE.11364031082016@88-209-239-
213.giganet.hu, says...



Here's a different suggestion. Put up as long a section (horizontal
except for the sag) as you can between the two trees. Say you can get
115 ft that way. Then extend each end 10 ft by adding a vertical wire
dropping down. Now the high current point on 80 m is way up in the air
where it will do the most good and the antenna won't be as much of a
cloud-warmer as your non-inverted V would have been.

Yet another suggestion: Just put what you can up there between the two
trees. So it's 20 ft or so short. Feed it with home-made open wire
(second choice: ladder-line). Use a good tuner. The main problem with
antennas slightly short of a half-wave long is that they have relatively
low resistance and appreciable capacitive reactance so feedline losses
go up. But if you use really low loss feedline they can still be pretty
good. For use on harmonics there is some advantage to avoiding an actual
half-wave on 80 m since that will have very high impedance on even
harmonics and with some feedline lengths can be very hard to match.

David VE7EZM and AF7BZ

Thanks for all the ideas. That is not the only antenna I have for the
low bands. I do have a 60 foot tower and triband on it. Also an off
center fed antenna in another directionthat is long enough to be almost
flat.

If one of the ropes had not grown into the tree, I might be tempted to
try loading it near the end, but I can not get that end down now.

Most of my work on 80 meters is just some friends in the state and not
not much DX so the cloud warmer is really to my advantage on 80.

I was just courious as to what patern it may be for that U or V shaped
antenna as I don't recall seeing a computer plot of one. Just the flat
top and inverted V antennas.



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