Help with dipole please?
 

Hi,
Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly? I have to put it into two trees to get
height. Are there any good links or sights to learn proper making and
installation?
Thanks.

Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly

Hammer, An all band dipole should not be fed with coax. On many of the bands
you want to work, the coax will have too much loss, and may fail due to the
extreme voltages that may be present.
A better choice would be a dipole, as long and high as you can make it. Feed
it with 450 ohm ladder line to an antenna tuner in your shack. The 1:1 balun
should insert between the line and your tuner. You now have an all band
efficient dipole.
BTW the antenna newsgroup would be better to ask this type of question, you
will get loads of answers there.
73 Gary N4AST

Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly

Hammer, An all band dipole should not be fed with coax. On many of the bands
you want to work, the coax will have too much loss, and may fail due to the
extreme voltages that may be present.
A better choice would be a dipole, as long and high as you can make it. Feed
it with 450 ohm ladder line to an antenna tuner in your shack. The 1:1 balun
should insert between the line and your tuner. You now have an all band
efficient dipole.
BTW the antenna newsgroup would be better to ask this type of question, you
will get loads of answers there.
73 Gary N4AST

Hammer wrote:
Hi,
Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly? I have to put it into two trees to get
height. Are there any good links or sights to learn proper making and
installation?

A lot depends on how much space you have.

A straight dipole with a 1:1 balun and coax will only cover one band.
Well, maybe two if you cut it for 40 meters. (it'll then work OK on 15
as well)

You have a few other options:

- Make the dipole as long as possible (the exact length is unimportant);
don't use the balun; use ladder line instead of coax; and connect it to
a tuner in the shack.

- Run several dipoles in parallel. 132' for 80m, 66' for 40m, 33' for
20m, etc. They can all share the same balun and coax.

- Trade the 1:1 balun for a 4:1 and put up an off-center-fed dipole. A
132' antenna, with 44' on one side and 88' on the other, will work well
on every band between 80 and 10 with the exception of 15. (and it's
close enough on 15 that if your rig has an autotuner, it'll work there
too)

I've got the latter antenna. It's the most "bang for the buck" in my
antenna collection. (it even works halfway decent for DXing the AM
broadcast band!)

A good general rule for wire antennas is as high as possible, as
straight as possible, and as far from obstructions as possible. And
don't sweat it if "as far as possible" isn't very far. (UNLESS the
obstruction is a power line!)
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com

Hammer wrote:
Hi,
Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly? I have to put it into two trees to get
height. Are there any good links or sights to learn proper making and
installation?

A lot depends on how much space you have.

A straight dipole with a 1:1 balun and coax will only cover one band.
Well, maybe two if you cut it for 40 meters. (it'll then work OK on 15
as well)

You have a few other options:

- Make the dipole as long as possible (the exact length is unimportant);
don't use the balun; use ladder line instead of coax; and connect it to
a tuner in the shack.

- Run several dipoles in parallel. 132' for 80m, 66' for 40m, 33' for
20m, etc. They can all share the same balun and coax.

- Trade the 1:1 balun for a 4:1 and put up an off-center-fed dipole. A
132' antenna, with 44' on one side and 88' on the other, will work well
on every band between 80 and 10 with the exception of 15. (and it's
close enough on 15 that if your rig has an autotuner, it'll work there
too)

I've got the latter antenna. It's the most "bang for the buck" in my
antenna collection. (it even works halfway decent for DXing the AM
broadcast band!)

A good general rule for wire antennas is as high as possible, as
straight as possible, and as far from obstructions as possible. And
don't sweat it if "as far as possible" isn't very far. (UNLESS the
obstruction is a power line!)
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com

"Hammer" wrote in message
...
Hi,
Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly? I have to put it into two trees to get
height. Are there any good links or sights to learn proper making and
installation?
Thanks.

A standard dipole will only work well on one band. However, if you put
several different dipoles together in parallel, you can have antennas for
different bands using the same feedpoint.

Check out:
http://www.geocities.com/n2uhc/2banddipole.com for more information. I use
a combination 20/40 meter dipole for portable operation with my QRP rigs.

Just keep in mind that the different elements for different bands will
interact with each other. If this weren't the case it would be feasable to
put elements for 80-10 together and use the same feedpoint. Since they do
interact, you may want to put together what's known as a fan dipole, where
the different elements are angled away from each other to cut down on the
interaction.

--
Tom Sevart N2UHC
Frontenac, KS
http://www.geocities.com/n2uhc

"Hammer" wrote in message
...
Hi,
Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly? I have to put it into two trees to get
height. Are there any good links or sights to learn proper making and
installation?
Thanks.

A standard dipole will only work well on one band. However, if you put
several different dipoles together in parallel, you can have antennas for
different bands using the same feedpoint.

Check out:
http://www.geocities.com/n2uhc/2banddipole.com for more information. I use
a combination 20/40 meter dipole for portable operation with my QRP rigs.

Just keep in mind that the different elements for different bands will
interact with each other. If this weren't the case it would be feasable to
put elements for 80-10 together and use the same feedpoint. Since they do
interact, you may want to put together what's known as a fan dipole, where
the different elements are angled away from each other to cut down on the
interaction.

--
Tom Sevart N2UHC
Frontenac, KS
http://www.geocities.com/n2uhc

A standard dipole will only work well on one band. However, if you put
several different dipoles together in parallel, you can have antennas for
different bands using the same feedpoint.
==========================
A single dipole will work well on many bands ,provided a balanced feeder of
300 - 450 or 600 Ohms (to name a few) is used ,obviously with a balanced to
unbalanced matching unit.
For this purpose I successfully use a 2 times 21 metres (68 ft) dipole with
a 450 Ohms ribbon feeder on all bands from 1.8 to 30 MHz. The length is not
all that critical although the dipole should preferably be half a wavelength
for the lower freq band used.
Because of its balanced behaviour the feeder does not radiate . In my case
the feeder runs into and over the loft into the lower level shack without RF
interference problems .

Frank GM0CSZ / KN6WH

A standard dipole will only work well on one band. However, if you put
several different dipoles together in parallel, you can have antennas for
different bands using the same feedpoint.
==========================
A single dipole will work well on many bands ,provided a balanced feeder of
300 - 450 or 600 Ohms (to name a few) is used ,obviously with a balanced to
unbalanced matching unit.
For this purpose I successfully use a 2 times 21 metres (68 ft) dipole with
a 450 Ohms ribbon feeder on all bands from 1.8 to 30 MHz. The length is not
all that critical although the dipole should preferably be half a wavelength
for the lower freq band used.
Because of its balanced behaviour the feeder does not radiate . In my case
the feeder runs into and over the loft into the lower level shack without RF
interference problems .

Frank GM0CSZ / KN6WH

On Sat, 7 Feb 2004 12:45:29 -0500, "Hammer"
wrote:

Hi,
Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly? I have to put it into two trees to get
height. Are there any good links or sights to learn proper making and
installation?
Thanks.

To keep things simple and multi-band I would suggest you try to feed
your dipole with open wire feeder and use a balanced tuner. You won't
need that balun. I have been doing that with a dipole cut for 80m and
it tunes well on ALL bands (even 160, but is not that great on that
band!) and works effectively for me. Of course you will get different
radiation patterns on each band - but it works and if you have a good
tuner it can be a very efficient antenna for QRP.

I have tried using multi-leg dipoles, G5RV's and trapped dipoles for
different bands but they are harder to set-up and simply did not work
as well for me. I believe your easiest multi-band option is what I
mentioned above.


You can even make your own open-wire feeders for next to nothing and
have a much longer, less lossy feedline than you would get with RG8
coax, especially on 10metres. Get the dipole up as high as possible.
It really is very simple and effective.

Larry Gagnon VE7EA
***************
remove "fake" from email address

On Sat, 7 Feb 2004 12:45:29 -0500, "Hammer"
wrote:

Hi,
Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly? I have to put it into two trees to get
height. Are there any good links or sights to learn proper making and
installation?
Thanks.

To keep things simple and multi-band I would suggest you try to feed
your dipole with open wire feeder and use a balanced tuner. You won't
need that balun. I have been doing that with a dipole cut for 80m and
it tunes well on ALL bands (even 160, but is not that great on that
band!) and works effectively for me. Of course you will get different
radiation patterns on each band - but it works and if you have a good
tuner it can be a very efficient antenna for QRP.

I have tried using multi-leg dipoles, G5RV's and trapped dipoles for
different bands but they are harder to set-up and simply did not work
as well for me. I believe your easiest multi-band option is what I
mentioned above.


You can even make your own open-wire feeders for next to nothing and
have a much longer, less lossy feedline than you would get with RG8
coax, especially on 10metres. Get the dipole up as high as possible.
It really is very simple and effective.

Larry Gagnon VE7EA
***************
remove "fake" from email address

On Sat, 7 Feb 2004 12:45:29 -0500, "Hammer"
wrote:

Hi,
Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly? I have to put it into two trees to get
height. Are there any good links or sights to learn proper making and
installation?
Thanks.

Also, make sure that one end of your dipole is fastened to the tree
with a weighted pulley system, so that when you get strong winds the
dipole won't snap. I run the line through a small pulley attached to
the tree and then hang a brick off the end of that line. Works very
well in winds to give the dipole some give.

Larry VE7EA
***************
remove "fake" from email address

On Sat, 7 Feb 2004 12:45:29 -0500, "Hammer"
wrote:

Hi,
Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this
dipole should be to work properly? I have to put it into two trees to get
height. Are there any good links or sights to learn proper making and
installation?
Thanks.

Also, make sure that one end of your dipole is fastened to the tree
with a weighted pulley system, so that when you get strong winds the
dipole won't snap. I run the line through a small pulley attached to
the tree and then hang a brick off the end of that line. Works very
well in winds to give the dipole some give.

Larry VE7EA
***************
remove "fake" from email address

Larry Gagnon wrote:

Also, make sure that one end of your dipole is fastened to the tree
with a weighted pulley system, so that when you get strong winds the
dipole won't snap. I run the line through a small pulley attached to
the tree and then hang a brick off the end of that line. Works very
well in winds to give the dipole some give.

I find that that system works well, though I've had to use a cinder-
block instead of a brick. I suspect that the weight of the mass on
the line is dependent on circumstances too numerous to enumerate.

Here in Oklahoma, it also serves well as a combined wind speed gauge
and wind direction indicator.

--
Mike Andrews

Tired old sysadmin

Larry Gagnon wrote:

Also, make sure that one end of your dipole is fastened to the tree
with a weighted pulley system, so that when you get strong winds the
dipole won't snap. I run the line through a small pulley attached to
the tree and then hang a brick off the end of that line. Works very
well in winds to give the dipole some give.

I find that that system works well, though I've had to use a cinder-
block instead of a brick. I suspect that the weight of the mass on
the line is dependent on circumstances too numerous to enumerate.

Here in Oklahoma, it also serves well as a combined wind speed gauge
and wind direction indicator.

--
Mike Andrews

Tired old sysadmin

Putting up a 10 through 160 or 10 through 80 meters dipole.... Are there
any good links or sights to learn proper making and installation?

Also, make sure that one end of your dipole is fastened to the tree
with a weighted pulley system, so that when you get strong winds the
dipole won't snap. I run the line through a small pulley attached to
the tree and then hang a brick off the end of that line....

DO be sure to fasten the weight with another rope so that if (when?)
the antenna does break, the brick won't fall on someone's head!

If one or both of the trees is liable to sway a LOT, you can add another
pully to the weight and run the rope back UP the tree to where the
first antenna pulley is; that way, one weight (which probably needs to
be heavier) can handle twich as much sway.

--Myron.
--
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)

Putting up a 10 through 160 or 10 through 80 meters dipole.... Are there
any good links or sights to learn proper making and installation?

Also, make sure that one end of your dipole is fastened to the tree
with a weighted pulley system, so that when you get strong winds the
dipole won't snap. I run the line through a small pulley attached to
the tree and then hang a brick off the end of that line....

DO be sure to fasten the weight with another rope so that if (when?)
the antenna does break, the brick won't fall on someone's head!

If one or both of the trees is liable to sway a LOT, you can add another
pully to the weight and run the rope back UP the tree to where the
first antenna pulley is; that way, one weight (which probably needs to
be heavier) can handle twich as much sway.

--Myron.
--
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)