Hello,

I just moved to a new location. My backyard has some 20 trees spread around
at a distance of 5 to max 10mtrs between each of them.
I would like to opt for a full size 40mtr(7Mhz) vertical and have (only)the
2 following options her:

1) full size 1/4 wire vertical inside fishing pole, mounted in a tree at a
foot height between 7 and 10mtrs from ground level. Some 4 elevated radials
will be added.

2) full size 1/4 wire vertical at ground level, parallel to a tree at a
distance of 0.5 till max 1 mtr. Ground screen will be some 16 pcs of wire
buried in the surrounding ground.



I have no clue about any effects of trees here. They are not pine trees.
There are lots of other parameters in the whole picture, but the trees is a
totally unkown factor for me.

Please share me your experiences.

Thanks in advance.

'73 Mark, PA5MW

On Thu, 27 Jan 2005 22:20:15 +0100, "M. van Wijk" pa5mwremove
all(incl) between @home.nl wrote:

Hello,

I just moved to a new location. My backyard has some 20 trees spread around
at a distance of 5 to max 10mtrs between each of them.
I would like to opt for a full size 40mtr(7Mhz) vertical and have (only)the
2 following options her:

1) full size 1/4 wire vertical inside fishing pole, mounted in a tree at a
foot height between 7 and 10mtrs from ground level. Some 4 elevated radials
will be added.

2) full size 1/4 wire vertical at ground level, parallel to a tree at a
distance of 0.5 till max 1 mtr. Ground screen will be some 16 pcs of wire
buried in the surrounding ground.



I have no clue about any effects of trees here. They are not pine trees.
There are lots of other parameters in the whole picture, but the trees is a
totally unkown factor for me.

Please share me your experiences.


Dear Mark,

I thought no one had many trees over there. There's a rumour that you
make shoes from trees. Can't be so - would be damned uncomfortable.

Anyway, trees are bad news for verticals. They absorb too much of the
energy - the closer you are to the tree, the more energy is induced in
the tree and dissipated as wasted heat. There is no data on this that
I am aware of, but I would say the effect is similar to that of
surrounding your antenna with the wood rafters and sheathing of an
attic.

My recommendation would be to get your energy running perpendicular to
the trees to minimize that coupling and hope for the best. In other
words, in your environment a poor dipole would be better than an
excellent vertical. In fact, that's usually my position even without
the tree problem - Hi!

Bob, W9DMK, Dahlgren, VA
Replace "nobody" with my callsign for e-mail
http://www.qsl.net/w9dmk
http://zaffora/f2o.org/W9DMK/W9dmk.html

Try the vertical off the ground, keeping the base of the antenna and four
radials about 3-4 meters off the ground. should work quite well and uses
less radials. Theoretically you can use two radials (worth comparing, you
may be pleasantly surprised).

Bill, W4WNT


"M. van Wijk" pa5mwremove all(incl) between @home.nl wrote in message
...
Hello,

I just moved to a new location. My backyard has some 20 trees spread
around
at a distance of 5 to max 10mtrs between each of them.
I would like to opt for a full size 40mtr(7Mhz) vertical and have
(only)the
2 following options her:

1) full size 1/4 wire vertical inside fishing pole, mounted in a tree at a
foot height between 7 and 10mtrs from ground level. Some 4 elevated
radials
will be added.

2) full size 1/4 wire vertical at ground level, parallel to a tree at a
distance of 0.5 till max 1 mtr. Ground screen will be some 16 pcs of wire
buried in the surrounding ground.



I have no clue about any effects of trees here. They are not pine trees.
There are lots of other parameters in the whole picture, but the trees is
a
totally unkown factor for me.

Please share me your experiences.

Thanks in advance.

'73 Mark, PA5MW

On Thu, 27 Jan 2005 22:20:15 +0100, "M. van Wijk" pa5mwremove
all(incl) between @home.nl wrote:

Hello,

I just moved to a new location. My backyard has some 20 trees spread around
at a distance of 5 to max 10mtrs between each of them.
I would like to opt for a full size 40mtr(7Mhz) vertical and have (only)the
2 following options her:

1) full size 1/4 wire vertical inside fishing pole, mounted in a tree at a
foot height between 7 and 10mtrs from ground level. Some 4 elevated radials
will be added.

2) full size 1/4 wire vertical at ground level, parallel to a tree at a
distance of 0.5 till max 1 mtr. Ground screen will be some 16 pcs of wire
buried in the surrounding ground.



I have no clue about any effects of trees here. They are not pine trees.
There are lots of other parameters in the whole picture, but the trees is a
totally unkown factor for me.

Please share me your experiences.

Thanks in advance.

'73 Mark, PA5MW



Don't take me for an expert here, but I like the option number 2.
While the tree may have some effect, I don't think it will stop your
signal or cause so much loss you can't be heard. However, the more
radials, the better. Rather than the four above ground radials, the
16 buried may produce better results.


--
Buck
N4PGW

"M. van Wijk" pa5mwremove all(incl) between @home.nl wrote in message
...
Hello,

I just moved to a new location. My backyard has some 20 trees spread
around
at a distance of 5 to max 10mtrs between each of them.
I would like to opt for a full size 40mtr(7Mhz) vertical and have
(only)the
2 following options her:

1) full size 1/4 wire vertical inside fishing pole, mounted in a tree at a
foot height between 7 and 10mtrs from ground level. Some 4 elevated
radials
will be added.

2) full size 1/4 wire vertical at ground level, parallel to a tree at a
distance of 0.5 till max 1 mtr. Ground screen will be some 16 pcs of wire
buried in the surrounding ground.



I have no clue about any effects of trees here. They are not pine trees.
There are lots of other parameters in the whole picture, but the trees is
a
totally unkown factor for me.

Please share me your experiences.

Thanks in advance.

'73 Mark, PA5MW


Mark,
I had a 40 m 1/4 vertical hanging from a tree branch. Feedpoint was about 8
meters above ground with 4 radials. On the average, performance was equal to
the 40 m dipole at 15 meters. It was about 3 meters from the tree trunk. If
you are going to have buried, or ground mounted radials, you would need a
lot more than 4. Oh, BTW, the tree is 25 m tall.

Tam/WB2TT

M=2E van Wijk (incl) wrote:
Hello,

I just moved to a new location. My backyard has some 20 trees spread
around
at a distance of 5 to max 10mtrs between each of them.
I would like to opt for a full size 40mtr(7Mhz) vertical and have
(only)the
2 following options her:

1) full size 1/4 wire vertical inside fishing pole, mounted in a tree
at a
foot height between 7 and 10mtrs from ground level. Some 4 elevated
radials
will be added.

2) full size 1/4 wire vertical at ground level, parallel to a tree at
a
distance of 0.5 till max 1 mtr. Ground screen will be some 16 pcs of
wire
buried in the surrounding ground.



I have no clue about any effects of trees here. They are not pine
trees.
There are lots of other parameters in the whole picture, but the
trees is a
totally unkown factor for me.

Please share me your experiences.

Thanks in advance.

You might consider a simple inverted L given all the trees you have
available. Build a very conventional half-wave coax-fed 40M dipole.
Suspend half of it (35 feet long?) vertically with the lower end a foot
or two above the ground from one tree then pull the other half more or
less horizontally to another tree. Pull the coax away from the elevated
feedpoint toward the Radio Room. Trim wires to resonance. No messy
radials needed and most likely you wouldn't need a tuner or "tuning
network" either. It would be just a standard inverted vee rotated 45=BA.
Half-wave inverted Ls without radials scream, been there, done 'em.

Research on the subject done by the U.S. Army years ago determined that
trees have no measurable effects on HF antennas. Trees do have an
effect on vhf/uhf antennas. There was a thread in this NG in the past
which addressed the topic in sdome detail and which is probably still
archived. Run a search on "Do Trees Absorb RF?"
=20
'73 Mark, PA5MW

w3rv

I also have recently moved to a new QTH. At my last, I was
a devotee of ground mounted verticals with many buried
radials. My main antenna there was a 42 foot vertical, with
48 buried radials, each about 50 feet long. This time, being
older and less inclined to digging, and work in general, but
still being a devotee of verticals, I decided to try a
vertical dipole in a tree. It is 28 feet long (tall), with
the bottom end inches off the ground. The feed is in the
middle with open wire line and an air-core balun. I use a
"balanced balanced" Richard Measures-style "L" network tuner
in the shack. The tree is a tall, skinny one, and the
vertical wire is about five feet from the tree. I have been
using it for about three months now, on 80 through 20
meters, mostly on my favorite, 40 cw.

I suppose at this point, following the pattern of others, I
should go into a dissertation on signal absorption by trees,
effect on pattern, effect of lack of radials, etc. I don't
have any first-hand information on all that, but I can say
that it works great for me. Performance is comparable to
the aforementioned vertical at my previous QTH, considering
that it is somewhat shorter. I certainly wouldn't advise
against trying one because of seemingly adverse theoretical
considerations.

Steve W9HJW

On 28 Jan 2005 04:38:01 -0800, wrote:


M. van Wijk (incl) wrote:
Hello,

I just moved to a new location. My backyard has some 20 trees spread
around
at a distance of 5 to max 10mtrs between each of them.
I would like to opt for a full size 40mtr(7Mhz) vertical and have
(only)the
2 following options her:

1) full size 1/4 wire vertical inside fishing pole, mounted in a tree
at a
foot height between 7 and 10mtrs from ground level. Some 4 elevated
radials
will be added.

2) full size 1/4 wire vertical at ground level, parallel to a tree at
a
distance of 0.5 till max 1 mtr. Ground screen will be some 16 pcs of
wire
buried in the surrounding ground.



I have no clue about any effects of trees here. They are not pine
trees.
There are lots of other parameters in the whole picture, but the
trees is a
totally unkown factor for me.

Please share me your experiences.

Thanks in advance.

You might consider a simple inverted L given all the trees you have
available. Build a very conventional half-wave coax-fed 40M dipole.
Suspend half of it (35 feet long?) vertically with the lower end a foot
or two above the ground from one tree then pull the other half more or
less horizontally to another tree. Pull the coax away from the elevated
feedpoint toward the Radio Room. Trim wires to resonance. No messy
radials needed and most likely you wouldn't need a tuner or "tuning
network" either. It would be just a standard inverted vee rotated 45º.
Half-wave inverted Ls without radials scream, been there, done 'em.

Research on the subject done by the U.S. Army years ago determined that
trees have no measurable effects on HF antennas. Trees do have an
effect on vhf/uhf antennas. There was a thread in this NG in the past
which addressed the topic in sdome detail and which is probably still
archived. Run a search on "Do Trees Absorb RF?"

'73 Mark, PA5MW

w3rv


Since he has room to hang a vertical, he can hang a slanted dipole
too. That would be a little directional but pointed in the right
direction it could be a great antenna.


--
Buck
N4PGW

On Fri, 28 Jan 2005 12:24:13 -0500, Buck wrote:

On 28 Jan 2005 04:38:01 -0800, wrote:


M. van Wijk (incl) wrote:
Hello,

I just moved to a new location. My backyard has some 20 trees spread
around
at a distance of 5 to max 10mtrs between each of them.
I would like to opt for a full size 40mtr(7Mhz) vertical and have
(only)the
2 following options her:

1) full size 1/4 wire vertical inside fishing pole, mounted in a tree
at a
foot height between 7 and 10mtrs from ground level. Some 4 elevated
radials
will be added.

2) full size 1/4 wire vertical at ground level, parallel to a tree at
a
distance of 0.5 till max 1 mtr. Ground screen will be some 16 pcs of
wire
buried in the surrounding ground.



I have no clue about any effects of trees here. They are not pine
trees.
There are lots of other parameters in the whole picture, but the
trees is a
totally unkown factor for me.

Please share me your experiences.

Thanks in advance.

You might consider a simple inverted L given all the trees you have
available. Build a very conventional half-wave coax-fed 40M dipole.
Suspend half of it (35 feet long?) vertically with the lower end a foot
or two above the ground from one tree then pull the other half more or
less horizontally to another tree. Pull the coax away from the elevated
feedpoint toward the Radio Room. Trim wires to resonance. No messy
radials needed and most likely you wouldn't need a tuner or "tuning
network" either. It would be just a standard inverted vee rotated 45º.
Half-wave inverted Ls without radials scream, been there, done 'em.

Research on the subject done by the U.S. Army years ago determined that
trees have no measurable effects on HF antennas. Trees do have an
effect on vhf/uhf antennas. There was a thread in this NG in the past
which addressed the topic in sdome detail and which is probably still
archived. Run a search on "Do Trees Absorb RF?"

'73 Mark, PA5MW

w3rv


Since he has room to hang a vertical, he can hang a slanted dipole
too. That would be a little directional but pointed in the right
direction it could be a great antenna.


OOPS! forget my last....

(remember to engage brain before fingers.)
--
Buck
N4PGW

Buck wrote:



Since he has room to hang a vertical, he can hang a slanted dipole
too. That would be a little directional but pointed in the right
direction it could be a great antenna.


OOPS! forget my last....

(remember to engage brain before fingers.)
Heh. We all do it. "Welcome to da club."

--
Buck
N4PGW

w3rv