RF in the Trees

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RF in the Trees

Edward A. Dauer
I have been playing with the two-tree solution to the one tree problem,
with a family of inverted Vees (and a K3 and KX3, for keeping this on
topic).  The "one tree problem" is that a Vee hoisted onto a top limb of a
coniferous tree is inevitably too close to if not tangled into the
branches below the apex.  So, I've been selecting two of the tallest
candidates a couple of hundred feet apart and stringing a stout nylon rope
between them.  In the middle of the cord I attach the balun for the Vees,
thereby allowing the legs to be in the clear, moveable from side to side,
and tied to smaller (8') trees at their distal ends.  In one variation on
the theme I had a 40 meter dipole as the center section of the supporting
rope, tied to the same balun as an 80 meter vee.  In another I tried a
linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't
perform as well as the full length version.

The surrounding forest is very likely still a problem, but that's life in
the woods.

Ted, KN1CBR


>
>Message: 8
>Date: Wed, 25 Jun 2014 12:14:27 -0700 (GMT-07:00)
>From: Fred Townsend <[hidden email]>
>To: Rstafford12 <[hidden email]>, [hidden email]
>Subject: Re: [Elecraft] extended double Zepp
>Message-ID:
> <[hidden email]>
>
>Content-Type: text/plain; charset=UTF-8
>
>Richard:
>I have run a double Zepp hung from the trees as you suggest. If you can
>do it I would get the antenna across the tops of the trees. 45' is too
>low for 80M unless you are running NVIS in which case you are too high at
>45'. Keep in mind that pine trees are parasitic so keep the wire, even if
>insulated, away from the trees. Inverted V works if you can't maintain
>60'.
>73,
>Fred, AE6QL
>
>
>-----Original Message-----
>>From: Rstafford12 <[hidden email]>
>>Sent: Jun 25, 2014 11:12 AM
>>To: [hidden email]
>>Subject: [Elecraft] extended double Zepp
>>
>>I realize this is another somewhat not on topic post, but it is in
>>regards to my KX1 and KX3. I have a mature pine forest; 60 -70 foot
>>trees. How compromised would an EDZ be hung 45 feet up about four rows
>>of trees in from the perimeter? No branches or needles inside the forest
>>until 50 feet up. Richard KD0NPM
>
>

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Re: RF in the Trees

Elecraft mailing list
I use a similar approach.  I have a very strong Kevlar line strung
between two tall trees and the dipoles are at least 40 feet from either
tree.  My dipoles at 60 feet out perform my beam at 30 feet by a
substantial margin.

Doug, K0DXV

On 6/25/14, 6:43 PM, Dauer, Edward wrote:

> I have been playing with the two-tree solution to the one tree problem,
> with a family of inverted Vees (and a K3 and KX3, for keeping this on
> topic).  The "one tree problem" is that a Vee hoisted onto a top limb of a
> coniferous tree is inevitably too close to if not tangled into the
> branches below the apex.  So, I've been selecting two of the tallest
> candidates a couple of hundred feet apart and stringing a stout nylon rope
> between them.  In the middle of the cord I attach the balun for the Vees,
> thereby allowing the legs to be in the clear, moveable from side to side,
> and tied to smaller (8') trees at their distal ends.  In one variation on
> the theme I had a 40 meter dipole as the center section of the supporting
> rope, tied to the same balun as an 80 meter vee.  In another I tried a
> linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't
> perform as well as the full length version.
>
> The surrounding forest is very likely still a problem, but that's life in
> the woods.
>
> Ted, KN1CBR
>
>
>> Message: 8
>> Date: Wed, 25 Jun 2014 12:14:27 -0700 (GMT-07:00)
>> From: Fred Townsend <[hidden email]>
>> To: Rstafford12 <[hidden email]>, [hidden email]
>> Subject: Re: [Elecraft] extended double Zepp
>> Message-ID:
>> <[hidden email]>
>>
>> Content-Type: text/plain; charset=UTF-8
>>
>> Richard:
>> I have run a double Zepp hung from the trees as you suggest. If you can
>> do it I would get the antenna across the tops of the trees. 45' is too
>> low for 80M unless you are running NVIS in which case you are too high at
>> 45'. Keep in mind that pine trees are parasitic so keep the wire, even if
>> insulated, away from the trees. Inverted V works if you can't maintain
>> 60'.
>> 73,
>> Fred, AE6QL
>>
>>
>> -----Original Message-----
>>> From: Rstafford12 <[hidden email]>
>>> Sent: Jun 25, 2014 11:12 AM
>>> To: [hidden email]
>>> Subject: [Elecraft] extended double Zepp
>>>
>>> I realize this is another somewhat not on topic post, but it is in
>>> regards to my KX1 and KX3. I have a mature pine forest; 60 -70 foot
>>> trees. How compromised would an EDZ be hung 45 feet up about four rows
>>> of trees in from the perimeter? No branches or needles inside the forest
>>> until 50 feet up. Richard KD0NPM
>>
> ______________________________________________________________
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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Re: RF in the Trees

Jim Brown-10
In reply to this post by Edward A. Dauer
On 6/25/2014 5:43 PM, Dauer, Edward wrote:
> So, I've been selecting two of the tallest
> candidates a couple of hundred feet apart and stringing a stout nylon rope
> between them.  In the middle of the cord I attach the balun for the Vees,
> thereby allowing the legs to be in the clear, moveable from side to side,
> and tied to smaller (8') trees at their distal ends.  In one variation on
> the theme I had a 40 meter dipole as the center section of the supporting
> rope, tied to the same balun as an 80 meter vee.  In another I tried a
> linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't
> perform as well as the full length version.

If you can suspend a flat antenna between two tall trees, why would you
want an inverted vee, which is a less effective radiator?

Your two trees 200 ft apart could support a full size 80/40 fan and a
20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good
antenna, and is easy to build.

My technique has evolved to starting with #8 bare copper from the big
box store, stretch it VERY slowly between a tree and a trailer hitch
until it breaks. Do this carefully where there's no one around to get
hurt. Now you have #10 hard drawn copper, which is pretty strong, and
pre-stretched. Use that for the longest dipole in each fan. Use #12 or
#14 THHN (house wire) for the other elements. I make spacers by cutting
1/2-in PVC conduit into lengths of about 16 in for 3-wire fans, and
about 12 inches for 2-wire fans. 5-6 ft between spacers is a good rule
of thumb. Hold the spacers in place by soldering short lengths of copper
around the spacer to the bare copper of the long element.

The higher your antenna is, the more robust your center insulator should
be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than
50 ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11
depending on the Z at resonance. Don't waste a dB or two with small
coax. My 110 ft 80/40 fans are fed with Belden 8213.

For weights, I fill 6 gallon water jugs with dry sand, and tie one to
one end of each span. The other end can be fixed. I have pulleys high my
trees. If you don't have a pulley and weight, your antenna WILL end up
on the ground, and it won't take a big storm for that to happen.

My HF antennas are all at the 110-120 ft level in a dense redwood forest
that towers 50-75 ft above them. They work. My "seat of the pants"
observation is that attenuation increases with frequency, and is
greatest with vertical polarization. 432 MHz is a waste of time, 2M sort
of works, and 6M works pretty well.

For an analysis of the value of height, study this. It supports the
statement earlier in this thread that a high dipole beats a low tri-bander.

http://k9yc.com/VertOrHorizontal-Slides.pdf

When Fred observes that the ends of antennas are "hotter," he means that
this is voltage maxima and a current minima, so good insulation is
needed to whatever the antenna is attached. I once melted heavy dacron
rope that was tied directly to the end of said dipole (well, twice,
actually). The extra ingredient was that it was wet. Duh.

73, Jim K9YC
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Re: RF in the Trees

Charlie T, K3ICH
Don't rule out traps.

Also, the RF Connection and probably others, sell a nice stranded copperweld
wire that has a black polyethylene insulation.  If I remember correctly, it
is 13 ga and is ideal for antennas.  For all practical purposes, it doesn't
stretch,  is fairly slippery  and only a little "springier" than hard drawn
copper.

I use those double ferrule aluminum crimp on's that are designed for
flexible wire cable to hold everything together.  I was concerned about them
holding through the poly insulation, but the following antenna has been up
for about ten years now.  It consists of a double (fan) dipole with a pair
of 80 meter traps in the top leg for 160 & 80 M coverage and a pair of 40
meter traps in the lower leg for 60 & 40 M coverage.  It is fed thru a 1:1
balun with RG-213 and is tuned for resonance.  Basically, I operate SSB 99%
of the time, so the antenna is tuned for that end of the bands.  An MN-2700
tuner in the shack takes care of  small excursions from resonance.  It's
only up about 50 feet, so performance is what you'd expect. It's not
straight either and is sort of a lazy Z, being strung between two 55'
telephone poles that are 105 feet apart.  The ends droop down at about 45
degrees to tie-off points in trees.  A compromise? Yes, but it works.

73, Charlie k3ICH




----- Original Message -----
From: "Jim Brown" <[hidden email]>
To: <[hidden email]>
Sent: Thursday, June 26, 2014 1:55 AM
Subject: Re: [Elecraft] RF in the Trees


> On 6/25/2014 5:43 PM, Dauer, Edward wrote:
>> So, I've been selecting two of the tallest
>> candidates a couple of hundred feet apart and stringing a stout nylon
>> rope
>> between them.  In the middle of the cord I attach the balun for the Vees,
>> thereby allowing the legs to be in the clear, moveable from side to side,
>> and tied to smaller (8') trees at their distal ends.  In one variation on
>> the theme I had a 40 meter dipole as the center section of the supporting
>> rope, tied to the same balun as an 80 meter vee.  In another I tried a
>> linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't
>> perform as well as the full length version.
>
> If you can suspend a flat antenna between two tall trees, why would you
> want an inverted vee, which is a less effective radiator?
>
> Your two trees 200 ft apart could support a full size 80/40 fan and a
> 20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good
> antenna, and is easy to build.
>
> My technique has evolved to starting with #8 bare copper from the big box
> store, stretch it VERY slowly between a tree and a trailer hitch until it
> breaks. Do this carefully where there's no one around to get hurt. Now you
> have #10 hard drawn copper, which is pretty strong, and pre-stretched. Use
> that for the longest dipole in each fan. Use #12 or #14 THHN (house wire)
> for the other elements. I make spacers by cutting 1/2-in PVC conduit into
> lengths of about 16 in for 3-wire fans, and about 12 inches for 2-wire
> fans. 5-6 ft between spacers is a good rule of thumb. Hold the spacers in
> place by soldering short lengths of copper around the spacer to the bare
> copper of the long element.
>
> The higher your antenna is, the more robust your center insulator should
> be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than 50
> ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11 depending
> on the Z at resonance. Don't waste a dB or two with small coax. My 110 ft
> 80/40 fans are fed with Belden 8213.
>
> For weights, I fill 6 gallon water jugs with dry sand, and tie one to one
> end of each span. The other end can be fixed. I have pulleys high my
> trees. If you don't have a pulley and weight, your antenna WILL end up on
> the ground, and it won't take a big storm for that to happen.
>
> My HF antennas are all at the 110-120 ft level in a dense redwood forest
> that towers 50-75 ft above them. They work. My "seat of the pants"
> observation is that attenuation increases with frequency, and is greatest
> with vertical polarization. 432 MHz is a waste of time, 2M sort of works,
> and 6M works pretty well.
>
> For an analysis of the value of height, study this. It supports the
> statement earlier in this thread that a high dipole beats a low
> tri-bander.
>
> http://k9yc.com/VertOrHorizontal-Slides.pdf
>
> When Fred observes that the ends of antennas are "hotter," he means that
> this is voltage maxima and a current minima, so good insulation is needed
> to whatever the antenna is attached. I once melted heavy dacron rope that
> was tied directly to the end of said dipole (well, twice, actually). The
> extra ingredient was that it was wet. Duh.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

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Re: RF in the Trees

Elecraft mailing list
In reply to this post by Jim Brown-10
This is an interesting discussion about antennas for forest regions where you have very tall trees.  I have a lot of trees, but getting an antenna to 45 or 50 feet would involve very small branches.  I have mostly Chinese Tallow Trees with some Ash and Beech, so stringing a wire from trees is marginal for me.  I do have a 65 foot tower and conductive soil, so the trombone elements from SteppIR work well for me.  You will be surprised how directive a rotatable dipole at 65 feet can be for 30 and 40 with 6 to 10 dB nulls at the ends and not much loss over a full dipole.  A 60 foot wire vertical from a ground stake to the top guy is a good 80 meter antenna and if you add an 80 meter trap and a drooping extension it pretty good for 160.  I have lived near a neighbor with 100 foot pine trees and I have seen them leaning nearly 45 degrees in 100 mile an hour winds during Hurricane Alicia.  I think a wire antenna would break.
 
Willis 'Cookie' Cooke, TDXS DX Chairman
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart


On Thursday, June 26, 2014 12:57 AM, Jim Brown <[hidden email]> wrote:
 


On 6/25/2014 5:43 PM, Dauer, Edward wrote:
> So, I've been selecting two of the tallest
> candidates a couple of hundred feet apart and stringing a stout nylon rope
> between them.  In the middle of the cord I attach the balun for the Vees,
> thereby allowing the legs to be in the clear, moveable from side to side,
> and tied to smaller (8') trees at their distal ends.  In one variation on
> the theme I had a 40 meter dipole as the center section of the supporting
> rope, tied to the same balun as an 80 meter vee.  In another I tried a
> linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but didn't
> perform as well as the full length version.

If you can suspend a flat antenna between two tall trees, why would you
want an inverted vee, which is a less effective radiator?

Your two trees 200 ft apart could support a full size 80/40 fan and a
20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good
antenna, and is easy to build.

My technique has evolved to starting with #8 bare copper from the big
box store, stretch it VERY slowly between a tree and a trailer hitch
until it breaks. Do this carefully where there's no one around to get
hurt. Now you have #10 hard drawn copper, which is pretty strong, and
pre-stretched. Use that for the longest dipole in each fan. Use #12 or
#14 THHN (house wire) for the other elements. I make spacers by cutting
1/2-in PVC conduit into lengths of about 16 in for 3-wire fans, and
about 12 inches for 2-wire fans. 5-6 ft between spacers is a good rule
of thumb. Hold the spacers in place by soldering short lengths of copper
around the spacer to the bare copper of the long element.

The higher your antenna is, the more robust your center insulator should
be. A high 80/40 dipole (80 ft or more) will be closer to 75 ohms than
50 ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or RG11
depending on the Z at resonance. Don't waste a dB or two with small
coax. My 110 ft 80/40 fans are fed with Belden 8213.

For weights, I fill 6 gallon water jugs with dry sand, and tie one to
one end of each span. The other end can be fixed. I have pulleys high my
trees. If you don't have a pulley and weight, your antenna WILL end up
on the ground, and it won't take a big storm for that to happen.

My HF antennas are all at the 110-120 ft level in a dense redwood forest
that towers 50-75 ft above them. They work. My "seat of the pants"
observation is that attenuation increases with frequency, and is
greatest with vertical polarization. 432 MHz is a waste of time, 2M sort
of works, and 6M works pretty well.

For an analysis of the value of height, study this. It supports the
statement earlier in this thread that a high dipole beats a low tri-bander.

http://k9yc.com/VertOrHorizontal-Slides.pdf

When Fred observes that the ends of antennas are "hotter," he means that
this is voltage maxima and a current minima, so good insulation is
needed to whatever the antenna is attached. I once melted heavy dacron
rope that was tied directly to the end of said dipole (well, twice,
actually). The extra ingredient was that it was wet. Duh.

73, Jim K9YC
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Re: RF in the Trees

Elecraft mailing list
In reply to this post by Jim Brown-10
The K9YC modelling with EZNEC
<http://k9yc.com/VertOrHorizontal-Slides.pdf> is quite interesting.  
Certainly has me thinking about vertical dipoles.  The half-wave end-fed
looks like the perfect candidate for a simple vertical dipole.

Doug -- K0DXV

On 6/25/14, 11:55 PM, Jim Brown wrote:

> On 6/25/2014 5:43 PM, Dauer, Edward wrote:
>> So, I've been selecting two of the tallest
>> candidates a couple of hundred feet apart and stringing a stout nylon
>> rope
>> between them.  In the middle of the cord I attach the balun for the
>> Vees,
>> thereby allowing the legs to be in the clear, moveable from side to
>> side,
>> and tied to smaller (8') trees at their distal ends.  In one
>> variation on
>> the theme I had a 40 meter dipole as the center section of the
>> supporting
>> rope, tied to the same balun as an 80 meter vee.  In another I tried a
>> linear-loaded 80-meter Vee, about 45' on a leg; it loaded fine but
>> didn't
>> perform as well as the full length version.
>
> If you can suspend a flat antenna between two tall trees, why would
> you want an inverted vee, which is a less effective radiator?
>
> Your two trees 200 ft apart could support a full size 80/40 fan and a
> 20/15/10 fan, in line with each other. A high 80/40 fan is a VERY good
> antenna, and is easy to build.
>
> My technique has evolved to starting with #8 bare copper from the big
> box store, stretch it VERY slowly between a tree and a trailer hitch
> until it breaks. Do this carefully where there's no one around to get
> hurt. Now you have #10 hard drawn copper, which is pretty strong, and
> pre-stretched. Use that for the longest dipole in each fan. Use #12 or
> #14 THHN (house wire) for the other elements. I make spacers by
> cutting 1/2-in PVC conduit into lengths of about 16 in for 3-wire
> fans, and about 12 inches for 2-wire fans. 5-6 ft between spacers is a
> good rule of thumb. Hold the spacers in place by soldering short
> lengths of copper around the spacer to the bare copper of the long
> element.
>
> The higher your antenna is, the more robust your center insulator
> should be. A high 80/40 dipole (80 ft or more) will be closer to 75
> ohms than 50 ohms. A 20/15/10 fan will be close to 50 ohms. Use RG8 or
> RG11 depending on the Z at resonance. Don't waste a dB or two with
> small coax. My 110 ft 80/40 fans are fed with Belden 8213.
>
> For weights, I fill 6 gallon water jugs with dry sand, and tie one to
> one end of each span. The other end can be fixed. I have pulleys high
> my trees. If you don't have a pulley and weight, your antenna WILL end
> up on the ground, and it won't take a big storm for that to happen.
>
> My HF antennas are all at the 110-120 ft level in a dense redwood
> forest that towers 50-75 ft above them. They work. My "seat of the
> pants" observation is that attenuation increases with frequency, and
> is greatest with vertical polarization. 432 MHz is a waste of time, 2M
> sort of works, and 6M works pretty well.
>
> For an analysis of the value of height, study this. It supports the
> statement earlier in this thread that a high dipole beats a low
> tri-bander.
>
> http://k9yc.com/VertOrHorizontal-Slides.pdf
>
> When Fred observes that the ends of antennas are "hotter," he means
> that this is voltage maxima and a current minima, so good insulation
> is needed to whatever the antenna is attached. I once melted heavy
> dacron rope that was tied directly to the end of said dipole (well,
> twice, actually). The extra ingredient was that it was wet. Duh.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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Re: RF in the Trees

KU4AF
That's a good and useful presentation. Although they don't affect Jim's vertical vs. horizontal conclusions, slides 22, 26, and 73 contain errors confusing quarter- and half wavelengths for 160/80/40 meters (i.e. 133 ft is a quarter wave on 160, not a half wave).

John, KU4AF
Pittsboro, NC

Elecraft mailing list wrote
The K9YC modelling with EZNEC
<http://k9yc.com/VertOrHorizontal-Slides.pdf> is quite interesting.  
Certainly has me thinking about vertical dipoles.  The half-wave end-fed
looks like the perfect candidate for a simple vertical dipole.

Doug -- K0DXV
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Re: RF in the Trees

Jim Brown-10
On 6/26/2014 9:17 AM, KU4AF wrote:
> Although they don't affect Jim's
> vertical vs. horizontal conclusions, slides 22, 26, and 73 contain errors
> confusing quarter- and half wavelengths for 160/80/40 meters (i.e. 133 ft is
> a quarter wave on 160, not a half wave).

Thanks John. I had fixed that at least a month ago, but the corrected
version didn't get to the website correctly. It's corrected now.

73, Jim K9YC


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Re: RF in the Trees

Edward R Cole
In reply to this post by Edward A. Dauer
I have used trees to hang "wire" in the past.

Now I use "metal trees" i.e. Rohn-25 and Rohn-45 metal trees.  Much
easier to climb and they do not sway near as much.  Truthfully, the
forest does not reach much higher than50-60 feet in my part of
Alaska.  We get 50-60 mph winds each year (mainly in Nov-Dec) which
lays the native white spruce and birch trees over to about 30 to 45
degrees off plumb and no pulley system will handle that violence.  I
had my anemometer blown off one of the towers last winter.  I guess
it registered 65 when I came apart.  Just got a phone call,
yesterday, that it had been rebuilt and on its way back from the factory.

Two falls ago we had some of the 60-foot spruce blown over that were
pulled out by the roots!  Had heavy rain for two months beforehand
that softened the soil.

I have two 50-foot ROHN-25 spaced 130 foot ad run an inverted-L
between them and a 80/40m inverted-V hung from 40-feet on one at
right angles to the inverted-L (which is tuned to 600m).

We have one member of the ARRL Experimental Group on 600m that has
actually loaded a pine tree to act as a vertical antenna,  He wrapped
a huge amount of wire around the base of the tree as a coupling coil.

73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
Dubus Mag business:
     [hidden email]

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Re: RF in the Trees

Phil Hystad-3
My only method of raising wire into the air to act as dipoles (actually fan dipoles) are trees -- nice tall straight trees.  In my case, Douglas Fir, Red Cedar, and Hemlock.  Each tree is about 80 to 95 feet tall.  I don't climb these trees though.  All antennas launched via bow & arrow with heavy fishing line that lifts up dacron line that lifts up insulated #12 house wire.

One of my antennas is a 80/40 fan dipole with a home-made balun at the center (created with the help of Jim's, K9YC, RFI paper).  The other is a 30-meter dipole.  Wires up about 50 feet elevation.

Never have had a problem and I have only had one break and I think that was caused by a squirrel looking for food inside of 3/8th Dacron line wrapped over the top of a tree branch.  No problem, I'm getting pretty good with the bow & arrow method of launching.

73, phil, K7PEH

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Re: RF in the Trees

Brian Hunt
In reply to this post by Elecraft mailing list
Jim's presentation is excellent, covering lots of trade-offs that most
of us face putting up antennas.  There are a couple (at least) other
aspects that should be considered.

I've been using an end fed half wave vertical for several years with my
K1 for portable ops.  It's easy to put up on a 33 ft  fiberglass pole
and covers 40, 30, and 20 using loading coils on the lower bands.  I
couple it to the 50 ohm feed line using a link coupled tuned tank
circuit to accommodate the very high feed point impedance.  Since that
impedance can be in the k-ohms, and the voltages involved increase as
the square of the power, this setup is strictly a QRP deal.  If I try to
use more than about 20 w the toroid in the coupler begins to arc like a
Tesla coil.

The other thing I have encountered with verticals vs horizontal antennas
in an urban environment is that verticals are inherently noisier.  For
weak signal situations (QRP Fox Hunts) I've compared the above vertical
with my inverted V and found that the V wins out on receive SNR most of
the time.  I've noticed the same thing comparing vertical vs horizontal
feed setups on a 20 m delta loop I had up for a while.

73,
Brian, K0DTJ


On 6/26/2014 7:59 AM, Doug Person via Elecraft wrote:
> Certainly has me thinking about vertical dipoles.  The half-wave
> end-fed looks like the perfect candidate for a simple vertical dipole.

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Re: RF in the Trees

k6dgw
On 6/26/2014 1:38 PM, Brian Hunt wrote:

> I've been using an end fed half wave vertical for several years with my
> K1 for portable ops.

EFHW's are very popular with the Summits On The Air crowd, and there are
several varieties of transformers that will get the impedance down to
what the ATU in a QRP rig can handle.  Some have added links for band
change, KT5X has a trapped EFHW.
>
> The other thing I have encountered with verticals vs horizontal antennas
> in an urban environment is that verticals are inherently noisier.

True ... not always, but as a rule of thumb from many years ago, a
vertical will likely be noisier.  I have a GAP Titan up on the roof that
I use for the top two WARC bands mostly.  My other two wires will
radiate but because the antennas are large compared to the wavelength,
they tend to squirt my RF in all sorts of useless directions.  There are
times, however, that the vertical is as quiet as the tribander on 20m.

I'm always amazed at how well my magnetic loop works when in the field.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org


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Re: RF in the Trees

Tony Estep
In reply to this post by Phil Hystad-3
On Thu, Jun 26, 2014 at 2:19 PM, Phil Hystad <[hidden email]> wrote:

> ....I'm getting pretty good with the bow & arrow method....

===========
For years I used a slingshot, firing a weight attached to a spinning reel.
Worked pretty good. But last year I bought one of these gadgets:
http://www.kr4loairboss.com/

It has a certain gee-whiz factor that makes you feel like a naughty kid.

Tony KT0NY
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Re: RF in the Trees

Victor Rosenthal 4X6GP
In reply to this post by Brian Hunt
I have a theory about this.

Compare a vertical to a dipole. One reason for additional noise is that
a vertical is omnidirectional, and noise comes from all directions. The
signal is coming from one direction, and if it is the right direction,
then the 2.2 dB gain from directivity of a dipole improves the s/n ratio
by that much. But subjectively the difference seems greater than this.
It's also true that the vertical is better for signals off the side of
the dipole.

As Brian said, most verticals appear to be far noisier in urban
environments where there is a lot of manmade noise. I believe that this
is /not/ because manmade noise tends to be vertically polarized, as is
often said.

I believe that it is because most verticals are not adequately decoupled
from the feedline. Therefore, manmade noise is picked up on the outside
of the feedline and flows directly into the antenna.

This is exactly the same problem that happens with a dipole without a balun.

Therefore the solution to the problem may be a good choke 'balun' at the
vertical's feedpoint.

On 6/26/14 1:38 PM, Brian Hunt wrote:
> The other thing I have encountered with verticals vs horizontal antennas
> in an urban environment is that verticals are inherently noisier.

--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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Re: RF in the Trees

Rick WA6NHC
In reply to this post by Tony Estep
This may be off topic, but in light of it being Field Day Weekend in the US....

The problem with the bow or slingshot is when (if) the projectile comes down.  

The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down.  Should it comes later, the risks of impalement can ruin the day.

The slingshot can improve over the arrow by increasing mass but can be equally dangerous.  Accurate shots are challenging.

Here is what I use (no pecuniary interest) and it solves those issues.
http://www.antennalaunchers.com/antlaunching.html 

It is simple to use, moderately safe (standard weapon rules about pointing etc) and accurate shots are simple.  I've used it to clear (and then some) 200' trees.

A weighted tennis ball (of a BRIGHT color so it can be seen) is simple to make an accurate shot; can pass through, then be pulled to earth by the increased mass.  If you clear the tree and want to shorten the flight path, simply touching the fishing line stops momentum immediately, the ball falls.

So there are several options, some safer than others, some more expensive and they all work.  What works best for you is the choice but please be safe and wear a hardhat.

I've also seen someone using the antenna launcher to shoot tennis balls for their dog to chase.  A 100 yard shot is pretty easily done.  By the time the (tiring) dog came back with the ball, the launcher was ready to shoot again.

73,
Rick, WA6NHC

iPad = small keypad = typos = sorry ;-)

> On Jun 26, 2014, at 3:02 PM, Tony Estep <[hidden email]> wrote:
>
>> On Thu, Jun 26, 2014 at 2:19 PM, Phil Hystad <[hidden email]> wrote:
>>
>> ....I'm getting pretty good with the bow & arrow method....
>
> ===========
> For years I used a slingshot, firing a weight attached to a spinning reel.
> Worked pretty good. But last year I bought one of these gadgets:
> http://www.kr4loairboss.com/
>
> It has a certain gee-whiz factor that makes you feel like a naughty kid.
>
> Tony KT0NY
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
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Re: RF in the Trees

W2RMS
I wonder if anyone's ever used a kite in a field to keep a wire "up".
I see kites a lot in the summer, along belt parkway here in Brooklyn and they seem to stay in one place for long periods of time.
I'm sure one can use 12 or 14 AWG wire and let a kite carry it pretty high. Of course you need wind for that but being near water (salt water, no less) there's usually wind present.
Hmm.....

Another idea that may be used to place a wire with a lot of precision is one of those RC quadricopters that are becoming wildly popular.
A little servo "claw" to release the wire or just to place it's apex where you want it...
__________________
Slava (Sal) B, W2RMS
[hidden email]

On Jun 26, 2014, at 7:12 PM, Rick Bates, WA6NHC <[hidden email]> wrote:

> This may be off topic, but in light of it being Field Day Weekend in the US....
>
> The problem with the bow or slingshot is when (if) the projectile comes down.  
>
> The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down.  Should it comes later, the risks of impalement can ruin the day.
>
> The slingshot can improve over the arrow by increasing mass but can be equally dangerous.  Accurate shots are challenging.
>
> Here is what I use (no pecuniary interest) and it solves those issues.
> http://www.antennalaunchers.com/antlaunching.html 
>
> It is simple to use, moderately safe (standard weapon rules about pointing etc) and accurate shots are simple.  I've used it to clear (and then some) 200' trees.
>
> A weighted tennis ball (of a BRIGHT color so it can be seen) is simple to make an accurate shot; can pass through, then be pulled to earth by the increased mass.  If you clear the tree and want to shorten the flight path, simply touching the fishing line stops momentum immediately, the ball falls.
>
> So there are several options, some safer than others, some more expensive and they all work.  What works best for you is the choice but please be safe and wear a hardhat.
>
> I've also seen someone using the antenna launcher to shoot tennis balls for their dog to chase.  A 100 yard shot is pretty easily done.  By the time the (tiring) dog came back with the ball, the launcher was ready to shoot again.
>
> 73,
> Rick, WA6NHC
>
> iPad = small keypad = typos = sorry ;-)
>
>> On Jun 26, 2014, at 3:02 PM, Tony Estep <[hidden email]> wrote:
>>
>>> On Thu, Jun 26, 2014 at 2:19 PM, Phil Hystad <[hidden email]> wrote:
>>>
>>> ....I'm getting pretty good with the bow & arrow method....
>>
>> ===========
>> For years I used a slingshot, firing a weight attached to a spinning reel.
>> Worked pretty good. But last year I bought one of these gadgets:
>> http://www.kr4loairboss.com/
>>
>> It has a certain gee-whiz factor that makes you feel like a naughty kid.
>>
>> Tony KT0NY
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Re: RF in the Trees

Phil Hystad-3
In reply to this post by Rick WA6NHC

> This may be off topic, but in light of it being Field Day Weekend in the US....
>
> The problem with the bow or slingshot is when (if) the projectile comes down.  
>
> The arrow has an issue because it gets hung up or in branches and doesn't have enough mass to pass through some branches or allow gravity to pull it down.  Should it comes later, the risks of impalement can ruin the day.
>
> The slingshot can improve over the arrow by increasing mass but can be equally dangerous.  Accurate shots are challenging.
>


In my case, the arrows I shoot up into and over trees always land on my property and I am the only one on my property at the time.  So, not much chance of hurting anyone.  I don't think my bow has enough power to launch an arrow off of my property.  Not that my property is that great, more that my bow is not that powerful (30 lb maximum pull).  It is just good enough to launch up into and over my trees.

I have never had an arrow get hung up in branches in all of my experience with the bow.  I think maybe I am just lucky though.

73, phil, K7PEH



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Re: RF in the Trees

k6dgw
In reply to this post by Rick WA6NHC
On 6/26/2014 4:12 PM, Rick Bates, WA6NHC wrote:
> This may be off topic, but in light of it being Field Day Weekend in
> the US....

It's radio, Eric will probably see it as relevant, unless we overdo it,
which we do at times. :-)

> The arrow has an issue because it gets hung up or in branches and
> doesn't have enough mass to pass through some branches or allow
> gravity to pull it down.  Should it comes later, the risks of
> impalement can ruin the day.

I wrapped some heavy, old solder I had around the arrow tip in two
layers, and then wrapped that with electrical tape.  So far, it's always
come down ... sometimes takes a little while with wind moving the
branches. The two layers of solder make the tip very blunt, impalement
is unlikely, bruise maybe if you don't have a hat on.

Regardless of how you do it, my experience is that an Inv-V with the
apex pulled up close to a limb but with the legs pulled out from the
tree works just fine.  It's hard to beat a horizontal 80m dipole with
the center between two 90 ft pine or fir trees more than a wavelength
apart, but sometimes we obsess about antennae minutiae.
>
> The slingshot can improve over the arrow by increasing mass but can
> be equally dangerous.  Accurate shots are challenging.

Arrow works better for me in the field, but the slingshot is a lot
smaller and lighter.  There's a reason arrows are long although the
sling worked for David, I guess.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

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RF in the Trees

Edward A. Dauer
In reply to this post by Edward A. Dauer
Now THAT is what being a ham is about!

OK, my part in this thread is over.  Loading a tree can't be topped.

Ted, KN1CBR


>
>We have one member of the ARRL Experimental Group on 600m that has
>actually loaded a pine tree to act as a vertical antenna,  He wrapped
>a huge amount of wire around the base of the tree as a coupling coil.
>
>73, Ed - KL7UW
>http://www.kl7uw.com
>     "Kits made by KL7UW"
>Dubus Mag business:
>     [hidden email]
>
>
>

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Re: RF in the Trees

k6dgw
In reply to this post by W2RMS
On 6/26/2014 4:24 PM, Slava Baytalskiy wrote:
> I wonder if anyone's ever used a kite in a field to keep a wire
> "up". I see kites a lot in the summer, along belt parkway here in
> Brooklyn and they seem to stay in one place for long periods of
> time. I'm sure one can use 12 or 14 AWG wire and let a kite carry it
> pretty high. Of course you need wind for that but being near water
> (salt water, no less) there's usually wind present. Hmm.....

The original German "Notsender," forerunner of the WW2 Gibson Girl
emergency beacon [AN/CRT-5] used a folded box kite, launched by a rocket
from an inflatable raft ... let's see -- rocket in an inflatable raft,
this conjures up many scenarios, most of them bad.  The CRT-5 operated
on the Holy Frequency [600 meters] and had a weighted copper braid to
drop overboard into the salt water, and the ones we had used balloons
inflated with hydrogen to lift the antenna.  That was problematical in
anything but a dead calm.  I doubt most kites in most situations would
handle #12 or even #14 wire, the high part of the wire ends up being a
long way up toward the kite.
>
> Another idea that may be used to place a wire with a lot of precision
> is one of those RC quadricopters that are becoming wildly popular. A
> little servo "claw" to release the wire or just to place it's apex
> where you want it

Monofilament line, sounds like a great idea!  Pull a Dacron line up and
then the wire.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

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