My antenna is similar to yours, but slightly longer. I have a 110 feet
dipole running between my chimney and a tree at the back of the lot. The
dipole is at a height of 30 feet and is fed with open-wire. I use an antenna
tuner and the antenna works fairly well on all bands 80 through 10 meters.

John, N9JG

"Cecil Moore" wrote in message
.. .
Andre & Sharon Walker wrote:
I was hoping to get away from traps, but i dont think its possible :-(. I
only have a smallish yard, with just 30m from the chimmny (brick ) to the
back of the yard, so i think a decent wire antenna is out...but i am open
to
suggestions. I guess the other considerstion is to keep "she inside"
happy .

A 1/2WL dipole is 20m on 40m and can be made to work on
all HF bands 40m-10m. That's probably what I would do
and then do something romantic to keep the XYL happy.
--
73, Cecil http://www.w5dxp.com

John, N9JG wrote:
My antenna is similar to yours, but slightly longer. I have a 110 feet
dipole running between my chimney and a tree at the back of the lot. The
dipole is at a height of 30 feet and is fed with open-wire. I use an antenna
tuner and the antenna works fairly well on all bands 80 through 10 meters.

Your dipole is 8 feet longer than the G5RV length which
is a positive for 80m operation. For your favorite bands,
there is probably an optimum length of feedline. EZNEC
allows one to model different lengths of feedline. I
wrote a compiled BASIC DOS program that will estimate
the optimum lengths of feedline at:

http://www.w5dxp.com/imax.exe
--
73, Cecil http://www.w5dxp.com

What do you mean by optimum length since open-wire feedline has minimal
loss? When I moved into this property last July, I just strung the longest
wire that would fit into the lot, and reeled out the amount of feedline that
would reach between the tuner and my shack on the second floor. I can not
make the feedline appreciably shorter, and if I made it longer I would have
to figure out how to support the additional feedline. I estimate the
feedline has a length of 70 feet.

John, N9JG

"Cecil Moore" wrote in message
et...
John, N9JG wrote:
My antenna is similar to yours, but slightly longer. I have a 110 feet
dipole running between my chimney and a tree at the back of the lot. The
dipole is at a height of 30 feet and is fed with open-wire. I use an
antenna tuner and the antenna works fairly well on all bands 80 through
10 meters.

Your dipole is 8 feet longer than the G5RV length which
is a positive for 80m operation. For your favorite bands,
there is probably an optimum length of feedline. EZNEC
allows one to model different lengths of feedline. I
wrote a compiled BASIC DOS program that will estimate
the optimum lengths of feedline at:

http://www.w5dxp.com/imax.exe
--
73, Cecil http://www.w5dxp.com

John, N9JG wrote:
What do you mean by optimum length since open-wire feedline has minimal
loss?

By "optimum length", I mean the length where you can
switch your antenna tuner into bypass mode and obtain
a 50 ohm SWR of less than ~1.6:1. For any dipole that
is 1/2WL on the lowest frequency of operation, that
will be at an SWR current maximum point making the
antenna plus tuned feeder system resonant without a tuner.

On 20m, for example, if one can vary the ladder-line
length by plus or minus 15 feet, one can always locate
the SWR current maximum point and usually bypass the
antenna tuner. I have a 20m 1/2WL dipole that I use
on 20m, 17m, 15m, 12m, 10m, and 6m without a conventional
antenna tuner by simply varying the length of the
300 ohm ladder-line.
--
73, Cecil http://www.w5dxp.com

Thanks for the explanation. What you have described would be more convenient
from an operating standpoint since I would have one less thing to tune
during a QSY.

"Cecil Moore" wrote in message
t...
John, N9JG wrote:
What do you mean by optimum length since open-wire feedline has minimal
loss?

By "optimum length", I mean the length where you can
switch your antenna tuner into bypass mode and obtain
a 50 ohm SWR of less than ~1.6:1. For any dipole that
is 1/2WL on the lowest frequency of operation, that
will be at an SWR current maximum point making the
antenna plus tuned feeder system resonant without a tuner.

On 20m, for example, if one can vary the ladder-line
length by plus or minus 15 feet, one can always locate
the SWR current maximum point and usually bypass the
antenna tuner. I have a 20m 1/2WL dipole that I use
on 20m, 17m, 15m, 12m, 10m, and 6m without a conventional
antenna tuner by simply varying the length of the
300 ohm ladder-line.
--
73, Cecil http://www.w5dxp.com

"John, N9JG" wrote in
et:

Thanks for the explanation. What you have described would be more
convenient from an operating standpoint since I would have one less
thing to tune during a QSY.

You might have misunderstood Cecil. I think he is describing a system where
the "optimal length" may be different on each band, so whilst you don't
tune an ATU, you tune the feeder length.

Cecil will confirm or deny... Owen

Owen Duffy wrote:
"John, N9JG" wrote in
et:

Thanks for the explanation. What you have described would be more
convenient from an operating standpoint since I would have one less
thing to tune during a QSY.

You might have misunderstood Cecil. I think he is describing a system where
the "optimal length" may be different on each band, so whilst you don't
tune an ATU, you tune the feeder length.

Throwing a couple of knife switches is certainly an easier
and faster QSY than rotating a coil switch and twisting
two interacting capacitor knobs.
--
73, Cecil http://www.w5dxp.com