Re: Topband: Fwd: Re: Drone and pulley

[Grant Saviers]

The are a number of drone remote releases available.  Given the small 
payload capacity of cheap drones the weight is critical for everything - 
line + release + sinker.  The polyethylene woven fishing line has 
amazing strength and low weight.  I use it for my tennis ball launcher 
to top 120' straight up shots.


Grant KZ1W

On 11/27/2018 14:21 PM, WW3S wrote:

There are some amazing drone videos on K3LR website

Sent from my iPad


On Nov 27, 2018, at 5:11 PM, terry burge  wrote:

Interesting about the drones. I want to get one or maybe have someone who runs 
them take a video of my tower and place. High quality video that is. If you 
ever watch youtube/Andrew Caramata doing his property management/excavation 
stuff you will be amazed by how long his video are and the distances he flies 
with his drone. He even has a video where he takes it apart and does a repair 
on the camera mount system to get it to run smoothly. I'm a real fan of this 
youtube videos about the arborist/tree climbing pruning and tree removing 
(don't know exactly what to call it). Ace Tree out of VK land has some awesome 
videos. I could use someone around here like that but the one quote I got was 
over $1000.

With the drone I would think if you can come up with a mechanism to release the 
rope/fish line you could use a fishing weight about 1 to 1.5 oz and run you 
line over a tree and drop it. That would keep you from tangling up your drone 
coming down again.

Most of all they really can do some tremendous video with the drone!

Terry
KI7M



-- Original Message --
From: Mike Waters 
To: Tree , topband@contesting.com
Date: November 27, 2018 at 1:21 PM
Subject: Re: Topband: Drone and pulley

Oooh! Thanks! I didn't think of that.

73, Mike
www.w0btu.com



On Tue, Nov 27, 2018, 2:43 PM Tree  wrote:

Trying to picture how you bring a line down from the top of a tree with a
drone...  without it getting snagged.  Guess you need a weight of some kind
to pull the rope down and away from the propellers.

Tree N6TR


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Topband: Wednesday 160m DX Activity Night

[Roger Kennedy]

It's so frustrating that you always hear hundreds of stations on Top Band
whenever there's a contest on, or when there's some DX-pedition active on
the band . . . yet most of the time the band is dead !

I find it even more frustrating that there's often people posting lots
stations that are on the band using FT8 (which doesn't interest me in the
slightest) . . . yet NOBODY is on CW.

That's why last Winter I suggested a regular Wednesday Activity Night . . .
one evening when hopefully lots of stations would make the effort to come on
the band at the same time, so we could all work each other.

It was pretty successful . . . so hopefully we can make it work again this
Winter too !

I'll certainly be on the band from around 2300Z tomorrow night.

73 Roger G3YRO

_
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Re: Topband: Fwd: Re: Drone and pulley

[WW3S]

There are some amazing drone videos on K3LR website

Sent from my iPad

> On Nov 27, 2018, at 5:11 PM, terry burge  wrote:
> 
> Interesting about the drones. I want to get one or maybe have someone who 
> runs them take a video of my tower and place. High quality video that is. If 
> you ever watch youtube/Andrew Caramata doing his property 
> management/excavation stuff you will be amazed by how long his video are and 
> the distances he flies with his drone. He even has a video where he takes it 
> apart and does a repair on the camera mount system to get it to run smoothly. 
> I'm a real fan of this youtube videos about the arborist/tree climbing 
> pruning and tree removing (don't know exactly what to call it). Ace Tree out 
> of VK land has some awesome videos. I could use someone around here like that 
> but the one quote I got was over $1000.
> 
> With the drone I would think if you can come up with a mechanism to release 
> the rope/fish line you could use a fishing weight about 1 to 1.5 oz and run 
> you line over a tree and drop it. That would keep you from tangling up your 
> drone coming down again. 
> 
> Most of all they really can do some tremendous video with the drone!
> 
> Terry
> KI7M
> 
> 
>> -- Original Message --
>> From: Mike Waters 
>> To: Tree , topband@contesting.com
>> Date: November 27, 2018 at 1:21 PM
>> Subject: Re: Topband: Drone and pulley
>> 
>> Oooh! Thanks! I didn't think of that.
>> 
>> 73, Mike
>> www.w0btu.com
>> 
>> 
>>> On Tue, Nov 27, 2018, 2:43 PM Tree  wrote:
>>> 
>>> Trying to picture how you bring a line down from the top of a tree with a
>>> drone...  without it getting snagged.  Guess you need a weight of some kind
>>> to pull the rope down and away from the propellers.
>>> 
>>> Tree N6TR
>>> 
>> _
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Topband: Fwd: Re: Drone and pulley

[terry burge]

Interesting about the drones. I want to get one or maybe have someone who runs 
them take a video of my tower and place. High quality video that is. If you 
ever watch youtube/Andrew Caramata doing his property management/excavation 
stuff you will be amazed by how long his video are and the distances he flies 
with his drone. He even has a video where he takes it apart and does a repair 
on the camera mount system to get it to run smoothly. I'm a real fan of this 
youtube videos about the arborist/tree climbing pruning and tree removing 
(don't know exactly what to call it). Ace Tree out of VK land has some awesome 
videos. I could use someone around here like that but the one quote I got was 
over $1000.

With the drone I would think if you can come up with a mechanism to release the 
rope/fish line you could use a fishing weight about 1 to 1.5 oz and run you 
line over a tree and drop it. That would keep you from tangling up your drone 
coming down again. 

Most of all they really can do some tremendous video with the drone!

Terry
KI7M


> -- Original Message --
> From: Mike Waters 
> To: Tree , topband@contesting.com
> Date: November 27, 2018 at 1:21 PM
> Subject: Re: Topband: Drone and pulley
> 
> Oooh! Thanks! I didn't think of that.
> 
> 73, Mike
> www.w0btu.com
> 
> 
> On Tue, Nov 27, 2018, 2:43 PM Tree  wrote:
> 
> > Trying to picture how you bring a line down from the top of a tree with a
> > drone...  without it getting snagged.  Guess you need a weight of some kind
> > to pull the rope down and away from the propellers.
> >
> > Tree N6TR
> >
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
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Re: Topband: Drone and pulley

[Mike Waters]

Oooh! Thanks! I didn't think of that.

73, Mike
www.w0btu.com


On Tue, Nov 27, 2018, 2:43 PM Tree  wrote:

> Trying to picture how you bring a line down from the top of a tree with a
> drone...  without it getting snagged.  Guess you need a weight of some kind
> to pull the rope down and away from the propellers.
>
> Tree N6TR
>
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Drone and pulley

[AB2E Darrell]

Hi Mike,
FB on the drone to string the line.  Best of luck with it.
In case the initial 3/16 line is too heavy for the drone, I have a suggestion 
that might help.
I too mostly use 3/16 line for tree antenna projects. I use an air cannon made 
by a local, which has a fishing reel, and I use Daiwa braided line initially 
over the tree (J-Braid 
https://smile.amazon.com/gp/product/B00ZYQXKU2/ref=oh_aui_detailpage_o01_s00?ie=UTF8=1
 ). Then I haul the 3/16 dacron rope over the tree with braided line. I've 
never had it break, and it's extremely light weight.

I would be interested in how you make out with the drone. The air cannon 
generally works well, but a few times the line has tangled on the way over the 
tree as the projective (6in pvc 1/4in) passes through the tiny branches.

73 Darrell AB2E
Amazon.com : Daiwa J-Braid 300M 8-Strand Woven Round Braid Line : Sports  
Outdoors
Amazon.com : Daiwa J-Braid 300M 8-Strand Woven Round Braid Line : Sports  
Outdoors
smile.amazon.com



From: Topband  on behalf of Mike Waters 

Sent: Tuesday, November 27, 2018 3:32 PM
To: topband@contesting.com
Subject: Re: Topband: Drone and pulley

Hi Paul,

Happy to! That's my problem too, lots of trees too close together.

This is the drone I ordered:

https://www.amazon.com/DROCON-Brushless-minutes-Quadcopter-Distance/dp/B06XTNS8HF/ref=as_li_ss_tl?s=toys-and-games=UTF8=1508031043=1-4=mjx+bugs+3+BLUE=sl1=dglobe_affordable-20=76e02ecd1fd450e244867238228bfb10
Prices on drones have really come down.

My plan is to tie 3/16" braided nylon cord to the drone; take off
vertically from the S side of the tree about 50' away to at least twice the
tree's height, move straight N at that height, and then descend straight
down *at least* 50' past the tree. (I'm being overcautious.)

That line will then be used to pull a 1/4" or 3/8" nylon rope over the tree
and make a loop (tie the ends together). At those ends is where the metal
pulley will be, attached at that point with about 2 or 3 feet of rope to
keep it from touching the tree. The 14 AWG THHN wire for the inverted-L
will go through that pulley.

*This drone may or may not work. *It doesn't have features like GPS that
more expensive drones have.  I won't receive it until after the first week
in December.

73, Mike
www.w0btu.com


On Tue, Nov 27, 2018, 1:12 PM [private] wrote:

> Sir : could you tell me what drone and accessories you 're going to use
> for that pulley - in - the - tree job?
>
> My QTH is almost all trees ... shooting fishing line gets hopelessly
> tangled in a number of trees . Sure would like to "drop" a line from a
> drone.
>
>
_
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Re: Topband: Drone and pulley

[MrToby]

I test drove this method with a DJI Phantom and a remote release triggered
by flashing the drone's running lights.  The drone had no problem carrying
1/8" nylon rope 100' into sky and releasing.

Marshall, AA0FO

On Tue, Nov 27, 2018, 2:32 PM Mike Waters  Hi Paul,
>
> Happy to! That's my problem too, lots of trees too close together.
>
> This is the drone I ordered:
>
>
> https://www.amazon.com/DROCON-Brushless-minutes-Quadcopter-Distance/dp/B06XTNS8HF/ref=as_li_ss_tl?s=toys-and-games=UTF8=1508031043=1-4=mjx+bugs+3+BLUE=sl1=dglobe_affordable-20=76e02ecd1fd450e244867238228bfb10
> Prices on drones have really come down.
>
> My plan is to tie 3/16" braided nylon cord to the drone; take off
> vertically from the S side of the tree about 50' away to at least twice the
> tree's height, move straight N at that height, and then descend straight
> down *at least* 50' past the tree. (I'm being overcautious.)
>
> That line will then be used to pull a 1/4" or 3/8" nylon rope over the tree
> and make a loop (tie the ends together). At those ends is where the metal
> pulley will be, attached at that point with about 2 or 3 feet of rope to
> keep it from touching the tree. The 14 AWG THHN wire for the inverted-L
> will go through that pulley.
>
> *This drone may or may not work. *It doesn't have features like GPS that
> more expensive drones have.  I won't receive it until after the first week
> in December.
>
> 73, Mike
> www.w0btu.com
>
>
> On Tue, Nov 27, 2018, 1:12 PM [private] wrote:
>
> > Sir : could you tell me what drone and accessories you 're going to use
> > for that pulley - in - the - tree job?
> >
> > My QTH is almost all trees ... shooting fishing line gets hopelessly
> > tangled in a number of trees . Sure would like to "drop" a line from a
> > drone.
> >
> >
> _
> Searchable Archives: http://www.contesting.com/_topband - Topband
> Reflector
>
_
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Re: Topband: Drone and pulley

[Mike Waters]

Hi Paul,

Happy to! That's my problem too, lots of trees too close together.

This is the drone I ordered:

https://www.amazon.com/DROCON-Brushless-minutes-Quadcopter-Distance/dp/B06XTNS8HF/ref=as_li_ss_tl?s=toys-and-games=UTF8=1508031043=1-4=mjx+bugs+3+BLUE=sl1=dglobe_affordable-20=76e02ecd1fd450e244867238228bfb10
Prices on drones have really come down.

My plan is to tie 3/16" braided nylon cord to the drone; take off
vertically from the S side of the tree about 50' away to at least twice the
tree's height, move straight N at that height, and then descend straight
down *at least* 50' past the tree. (I'm being overcautious.)

That line will then be used to pull a 1/4" or 3/8" nylon rope over the tree
and make a loop (tie the ends together). At those ends is where the metal
pulley will be, attached at that point with about 2 or 3 feet of rope to
keep it from touching the tree. The 14 AWG THHN wire for the inverted-L
will go through that pulley.

*This drone may or may not work. *It doesn't have features like GPS that
more expensive drones have.  I won't receive it until after the first week
in December.

73, Mike
www.w0btu.com


On Tue, Nov 27, 2018, 1:12 PM [private] wrote:

> Sir : could you tell me what drone and accessories you 're going to use
> for that pulley - in - the - tree job?
>
> My QTH is almost all trees ... shooting fishing line gets hopelessly
> tangled in a number of trees . Sure would like to "drop" a line from a
> drone.
>
>
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Vertical antennas aren't always best for DX everywhere - the facts

[GEORGE WALLNER]

There is no such things as "best antenna".
When I lived in Arizona, I had on a hill-top a doublet with 300 foot arms at 
100 foot height (effectively more because of the hill-top). I used it both 
as a doublet and as a vertical T (with the two wires of the ladder line 
shorted). It had about 40 radials of various lengths, between 100 and 150 
feet. Almost always the doublet was better.
Now I live in FL, on an island, and my vertical is on the edge of the 
salt-water. It is only 45 foot tall with two top loading wires. It gets out 
very well and I have no interest in trying a dipole.
A lot depends on the location. I believe that it mostly has to do with the 
ground, but there are other factors that are harder to figure.
I used to operate mobile/portable from the Australian outback (mostly 
central and western Queensland). The ground there is generally very poor 
(low conductivity). I had a  a 20 foot vertical fed via a tuner and an 
inverted V doublet. I would stop every night, camp, throw on the ground a 
few "radials" and the doublet over a tree.I operated, mostly on 80 and 40 
meters. Different locations, with pretty much the same looking ground (dry 
dirt) gave very different results on the two antennas. Sometimes the doublet 
was better, sometimes the vertical, often both were either bad or good at 
the same time. Most of the time I could not pin-point the reason. Hill-top 
locations were not always the best. Near creeks or swamps, even from a 
valley, generally I got better results. But some of the best locations were 
totally unremarkable. I did this for more than 15 years, often visiting the 
same sites. There was a consistency: the good sites were good year after 
year and the bad ones stayed bad. 

Go figure...
73,
George

On Mon, 26 Nov 2018 15:19:58 -0600
 Mike Waters  wrote:

This has been an eye-opening discussion for me! I have always preached the
'gospel' of vertical-is-usually-best based on W8JI, ON4UN, and *many* other
long-time Topbanders. Someday I'll have to revise
www.w0btu.com/160_meters.html   and 
include a link to this thread.

I stand corrected. Thank you, gentlemen! :-)

73, Mike
www.w0btu.com  


On Mon, Nov 26, 2018, 12:56 AM Steve Ireland  wrote:

Hi Frank (and Rick)

Somewhere I have a map of the lines of geomagnetic latitude superimposed
on a Mercator projection of the world, but I can’t find it right now.
Unlike the ruler-straight lines of conventional latitude, geomagnetic
latitude lines wander across the world like a collection of snake tracks.

As a result of how geomagnetic latitude snakes across the globe, a
comparison can’t be directly made between similar geomagnetic latitudes in
the northern and southern hemispheres – where Tom W8JI lives is probably
very different to me in terms of the closeness of his geomagnetic latitude
to the electron gyro-frequency.  As Carl K9LA points out, the geomagnetic
latitude relates to polarization and involves the ordinary and
extraordinary waves that propagate through the ionosphere, and how 160m is
affected by being close to the electron gyro-frequency.

About 10 to 15 years ago, Carl, Nick Hall-Patch VE7DXR and Bob NM7M (SK)
(also a physicist like Carl, as I’m sure you recall) helped Mike VK6HD (SK)
and I to understand why our horizontal cloud-warmers outperformed efficient
vertical antenna systems in SW WA.

You are quite correct, the Fresnel zone where I live (the mostly far field
region where ground gain is developed) has very poor conductivity. And, to
repeat your point as this is not as widely known as it should be, poor
Fresnel Zone conductivity has very little impact on the performance of
horizontally polarized antennas, while having a major impact on vertically
polarised ones.

While the Fresnel (far field) zone of my location, is basically rock
(granite and ‘coffee rock’), Mike’s final location beside the Kalgan
estuary appeared to have much better Fresnel zone conductivity, with less
rock than me and, in around half the compass directions, salt water.
However, his inverted-L with an 80’ vertical section over 120 buried
quarter-wave radials at Kalgan performed only marginally better than our
previous attempts at vertical antenna systems did.

On this basis, I came to the conclusion that the dominant problem was
likely to be the geomagnetic latitude issue, rather than poor conductivity
in the Fresnel zone – which it certainly is also an issue here.

To investigate this further, I sought out the opportunity to operate
directly by the sea here with a good vertical antenna. After much
paperwork, I managed to get permission to operation from the Cape Leeuwin
lighthouse, which is 40m-plus high and on a narrow finger of land
surrounded by sea for over 300 degrees.

In a Stew Perry TBDC in the early 2000s, with the assistance of my friend
Phil VK6PH, we put up a full-sized quarter-wave wire vertical on the most
seaward side of the lighthouse, less than 60 metres from 

Re: Topband: Vertical antennas aren't always best for DX

[n4is]

John 

I think I understand where we disagree. Most low dipoles on 160m are 30 to
60 ft high, 1/4 wave high is not low for most stations. Very few can afford
a dipole at 120 ft high.
You right 50% is a ball parking number but it brings the attention to the
importance of 3D and separation between horizontal and vertical
polarization. In special on 160m, where I am a firm believer on two
different propagation path, one vert, and another horizontal.

By the way, what you mentioned about QSB is true, I observed this phenomenon
since the first year with the   HWF in 2009. QSB is  just a shift in
polarization between horizontal and vertical.

73's
JC
N4IS

-Original Message-
From: John Kaufmann  
Sent: Tuesday, November 27, 2018 9:36 AM
To: n...@n4is.com; topband@contesting.com
Subject: RE: Topband: Vertical antennas aren't always best for DX

JC, 

You said: " Every dipole or inverted V irradiate  50% of the power
horizontal polarized broadside with the wire and 50% of the power vertical
polarized along the wire."  You cited EZNEC as evidence.

I am merely pointing out that as a general rule, this is not true.  The
issue *is* math because that is precisely how you determine the fraction of
power that goes into horizontal polarization and into vertical polarization.
As I pointed out, the relevant math is a 3-dimensional integration of the
radiation pattern in spherical coordinates.  

Take a dipole that is 1/4 wavelength high, which we can all agree is "low"
in wavelength terms.  At a takeoff angle of 90 degrees (straight up), EZNEC
shows that the horizontal and vertical components of radiation are about the
same.  It is easy to think there is a 50/50 split in horizontal/vertical
power because of this.  However, this neglects the radiation at lower angles
where the large majority of the radiated power is produced.  At a 45 degree
takeoff angle, the broadside horizontal power dominates the vertical power
by about 4 dB and the ratio increases at lower angles.  If the dipole is
higher than 1/4 wavelength, the ratio becomes even greater.

The math does not lie.

73, John W1FV



-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
n...@n4is.com
Sent: Tuesday, November 27, 2018 8:50 AM
To: jkaufm...@alum.mit.edu; topband@contesting.com
Subject: Re: Topband: Vertical antennas aren't always best for DX

John

 

The issue here is not math. It is the interaction of fields and matter. A
good text book is Electromagnetic waves and radiating system  by Edward C
Jordan and Keith G. Balmain. Chapter 9.

 

You can not ignore the close proximity with ground on 160m antennas for both
transmit signal and receiving signal. Too close it became more a
transmission line, getting high the irradiation increase and the maximum
horizontal power radiated or receiving signal intensity are near 1 ½ wave
high. The take off angle depends on the ground itself.

 

73’s

JC

N4IS

 

From: John Kaufmann 
Sent: Tuesday, November 27, 2018 8:16 AM
To: n...@n4is.com; topband@contesting.com
Subject: RE: Topband: Vertical antennas aren't always best for DX

 

In considering the *total power* radiated by any antenna, you need to look
at the 3-dimensional antenna pattern, not a 2-dimensional slice.  The total
radiated power is the 3-dimensional integration of the 3-dimensional
radiation pattern.  It is convenient to do this in spherical coordinates
because that is how we visualize 3-dimensional patterns.   In spherical
coordinates the integration applies the *smallest* weighting at elevation
angles around zenith.  Even if the dipole is low, the calculation shows that
the fraction of power that goes straight up is small compared to the total
radiated power.   This is easily understood in 3-dimensional spherical
coordinates:
https://www.khanacademy.org/math/multivariable-calculus/integrating-multivar
iable-functions/triple-integrals-a/a/triple-integrals-in-spherical-coordinat
es.

73, John W1FV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
n...@n4is.com 
Sent: Tuesday, November 27, 2018 6:58 AM
To: jkaufm...@alum.mit.edu  ;
topband@contesting.com 
Subject: Re: Topband: Vertical antennas aren't always best for DX

Sorry ,  but all antenna's on 160m are close to the ground and it is the

case, you can check by yourself using EZENEC if you don't know how to

calculate the fields.

There is no misleading here.

73

JC

N4IS

 

-Original Message-

From: Topband mailto:topband-boun...@contesting.com> > On Behalf Of John Kaufmann

Sent: Monday, November 26, 2018 8:53 PM

To: topband@contesting.com  

Subject: Re: Topband: Vertical antennas aren't always best for DX

The statement that the half of a horizontal dipole's radiation is vertically

polarized is misleading and needs qualification.  There is a vertically

polarized component 

Re: Topband: Vertical antennas aren't always best for DX

[n4is]

Hi John

On EZNEC  for sure  3D. do not use total field, under description select
horizontal and vertical field only and see the red line , vertical field and
green line horizontal field, use real ground.

Look it again.

73's
JC

-Original Message-
From: John Kaufmann  
Sent: Tuesday, November 27, 2018 9:36 AM
To: n...@n4is.com; topband@contesting.com
Subject: RE: Topband: Vertical antennas aren't always best for DX

JC, 

You said: " Every dipole or inverted V irradiate  50% of the power
horizontal polarized broadside with the wire and 50% of the power vertical
polarized along the wire."  You cited EZNEC as evidence.

I am merely pointing out that as a general rule, this is not true.  The
issue *is* math because that is precisely how you determine the fraction of
power that goes into horizontal polarization and into vertical polarization.
As I pointed out, the relevant math is a 3-dimensional integration of the
radiation pattern in spherical coordinates.  

Take a dipole that is 1/4 wavelength high, which we can all agree is "low"
in wavelength terms.  At a takeoff angle of 90 degrees (straight up), EZNEC
shows that the horizontal and vertical components of radiation are about the
same.  It is easy to think there is a 50/50 split in horizontal/vertical
power because of this.  However, this neglects the radiation at lower angles
where the large majority of the radiated power is produced.  At a 45 degree
takeoff angle, the broadside horizontal power dominates the vertical power
by about 4 dB and the ratio increases at lower angles.  If the dipole is
higher than 1/4 wavelength, the ratio becomes even greater.

The math does not lie.

73, John W1FV



-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
n...@n4is.com
Sent: Tuesday, November 27, 2018 8:50 AM
To: jkaufm...@alum.mit.edu; topband@contesting.com
Subject: Re: Topband: Vertical antennas aren't always best for DX

John

 

The issue here is not math. It is the interaction of fields and matter. A
good text book is Electromagnetic waves and radiating system  by Edward C
Jordan and Keith G. Balmain. Chapter 9.

 

You can not ignore the close proximity with ground on 160m antennas for both
transmit signal and receiving signal. Too close it became more a
transmission line, getting high the irradiation increase and the maximum
horizontal power radiated or receiving signal intensity are near 1 ½ wave
high. The take off angle depends on the ground itself.

 

73’s

JC

N4IS

 

From: John Kaufmann 
Sent: Tuesday, November 27, 2018 8:16 AM
To: n...@n4is.com; topband@contesting.com
Subject: RE: Topband: Vertical antennas aren't always best for DX

 

In considering the *total power* radiated by any antenna, you need to look
at the 3-dimensional antenna pattern, not a 2-dimensional slice.  The total
radiated power is the 3-dimensional integration of the 3-dimensional
radiation pattern.  It is convenient to do this in spherical coordinates
because that is how we visualize 3-dimensional patterns.   In spherical
coordinates the integration applies the *smallest* weighting at elevation
angles around zenith.  Even if the dipole is low, the calculation shows that
the fraction of power that goes straight up is small compared to the total
radiated power.   This is easily understood in 3-dimensional spherical
coordinates:
https://www.khanacademy.org/math/multivariable-calculus/integrating-multivar
iable-functions/triple-integrals-a/a/triple-integrals-in-spherical-coordinat
es.

73, John W1FV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
n...@n4is.com 
Sent: Tuesday, November 27, 2018 6:58 AM
To: jkaufm...@alum.mit.edu  ;
topband@contesting.com 
Subject: Re: Topband: Vertical antennas aren't always best for DX

Sorry ,  but all antenna's on 160m are close to the ground and it is the

case, you can check by yourself using EZENEC if you don't know how to

calculate the fields.

There is no misleading here.

73

JC

N4IS

 

-Original Message-

From: Topband mailto:topband-boun...@contesting.com> > On Behalf Of John Kaufmann

Sent: Monday, November 26, 2018 8:53 PM

To: topband@contesting.com  

Subject: Re: Topband: Vertical antennas aren't always best for DX

The statement that the half of a horizontal dipole's radiation is vertically

polarized is misleading and needs qualification.  There is a vertically

polarized component off the ends of the dipole but it is only of consequence

at takeoff angles approaching 90 degrees, in other words straight overhead.

I would argue that these takeoff angles are of little interest for long

distance propagation.   

At takeoff angles lower than 60 degrees or so, the total radiation pattern

of a dipole at any reasonable height becomes dominated by the horizontally

polarized component that is broadside to 

Re: Topband: Vertical antennas aren't always best for DX

[John Kaufmann]

JC, 

You said: " Every dipole or inverted V irradiate  50% of the power
horizontal polarized broadside with the wire and 50% of the power vertical
polarized along the wire."  You cited EZNEC as evidence.

I am merely pointing out that as a general rule, this is not true.  The
issue *is* math because that is precisely how you determine the fraction of
power that goes into horizontal polarization and into vertical polarization.
As I pointed out, the relevant math is a 3-dimensional integration of the
radiation pattern in spherical coordinates.  

Take a dipole that is 1/4 wavelength high, which we can all agree is "low"
in wavelength terms.  At a takeoff angle of 90 degrees (straight up), EZNEC
shows that the horizontal and vertical components of radiation are about the
same.  It is easy to think there is a 50/50 split in horizontal/vertical
power because of this.  However, this neglects the radiation at lower angles
where the large majority of the radiated power is produced.  At a 45 degree
takeoff angle, the broadside horizontal power dominates the vertical power
by about 4 dB and the ratio increases at lower angles.  If the dipole is
higher than 1/4 wavelength, the ratio becomes even greater.

The math does not lie.

73, John W1FV



-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
n...@n4is.com
Sent: Tuesday, November 27, 2018 8:50 AM
To: jkaufm...@alum.mit.edu; topband@contesting.com
Subject: Re: Topband: Vertical antennas aren't always best for DX

John

 

The issue here is not math. It is the interaction of fields and matter. A
good text book is Electromagnetic waves and radiating system  by Edward C
Jordan and Keith G. Balmain. Chapter 9.

 

You can not ignore the close proximity with ground on 160m antennas for both
transmit signal and receiving signal. Too close it became more a
transmission line, getting high the irradiation increase and the maximum
horizontal power radiated or receiving signal intensity are near 1 ½ wave
high. The take off angle depends on the ground itself.

 

73’s

JC

N4IS

 

From: John Kaufmann  
Sent: Tuesday, November 27, 2018 8:16 AM
To: n...@n4is.com; topband@contesting.com
Subject: RE: Topband: Vertical antennas aren't always best for DX

 

In considering the *total power* radiated by any antenna, you need to look
at the 3-dimensional antenna pattern, not a 2-dimensional slice.  The total
radiated power is the 3-dimensional integration of the 3-dimensional
radiation pattern.  It is convenient to do this in spherical coordinates
because that is how we visualize 3-dimensional patterns.   In spherical
coordinates the integration applies the *smallest* weighting at elevation
angles around zenith.  Even if the dipole is low, the calculation shows that
the fraction of power that goes straight up is small compared to the total
radiated power.   This is easily understood in 3-dimensional spherical
coordinates:
https://www.khanacademy.org/math/multivariable-calculus/integrating-multivar
iable-functions/triple-integrals-a/a/triple-integrals-in-spherical-coordinat
es.

73, John W1FV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
n...@n4is.com  
Sent: Tuesday, November 27, 2018 6:58 AM
To: jkaufm...@alum.mit.edu  ;
topband@contesting.com  
Subject: Re: Topband: Vertical antennas aren't always best for DX

Sorry ,  but all antenna's on 160m are close to the ground and it is the

case, you can check by yourself using EZENEC if you don't know how to

calculate the fields.

There is no misleading here.

73

JC

N4IS

 

-Original Message-

From: Topband mailto:topband-boun...@contesting.com> > On Behalf Of John Kaufmann

Sent: Monday, November 26, 2018 8:53 PM

To: topband@contesting.com  

Subject: Re: Topband: Vertical antennas aren't always best for DX

The statement that the half of a horizontal dipole's radiation is vertically

polarized is misleading and needs qualification.  There is a vertically

polarized component off the ends of the dipole but it is only of consequence

at takeoff angles approaching 90 degrees, in other words straight overhead.

I would argue that these takeoff angles are of little interest for long

distance propagation.   

At takeoff angles lower than 60 degrees or so, the total radiation pattern

of a dipole at any reasonable height becomes dominated by the horizontally

polarized component that is broadside to the dipole.   The lower the angle

or the higher the dipole, the more insignificant the vertical component

becomes. This is all verifiable in EZNEC.  If this were not true, you would

not see the well-defined radiation patterns that are produced by HF Yagi's

at higher frequencies were the radiation is horizontally polarized for

virtually all signals of interest.

73, John W1FV

-Original Message-

From: Topband 

Re: Topband: Vertical antennas aren't always best for DX

[n4is]

John

 

The issue here is not math. It is the interaction of fields and matter. A
good text book is Electromagnetic waves and radiating system  by Edward C
Jordan and Keith G. Balmain. Chapter 9.

 

You can not ignore the close proximity with ground on 160m antennas for both
transmit signal and receiving signal. Too close it became more a
transmission line, getting high the irradiation increase and the maximum
horizontal power radiated or receiving signal intensity are near 1 ½ wave
high. The take off angle depends on the ground itself.

 

73’s

JC

N4IS

 

From: John Kaufmann  
Sent: Tuesday, November 27, 2018 8:16 AM
To: n...@n4is.com; topband@contesting.com
Subject: RE: Topband: Vertical antennas aren't always best for DX

 

In considering the *total power* radiated by any antenna, you need to look
at the 3-dimensional antenna pattern, not a 2-dimensional slice.  The total
radiated power is the 3-dimensional integration of the 3-dimensional
radiation pattern.  It is convenient to do this in spherical coordinates
because that is how we visualize 3-dimensional patterns.   In spherical
coordinates the integration applies the *smallest* weighting at elevation
angles around zenith.  Even if the dipole is low, the calculation shows that
the fraction of power that goes straight up is small compared to the total
radiated power.   This is easily understood in 3-dimensional spherical
coordinates:
https://www.khanacademy.org/math/multivariable-calculus/integrating-multivar
iable-functions/triple-integrals-a/a/triple-integrals-in-spherical-coordinat
es.

73, John W1FV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
n...@n4is.com  
Sent: Tuesday, November 27, 2018 6:58 AM
To: jkaufm...@alum.mit.edu  ;
topband@contesting.com  
Subject: Re: Topband: Vertical antennas aren't always best for DX

Sorry ,  but all antenna's on 160m are close to the ground and it is the

case, you can check by yourself using EZENEC if you don't know how to

calculate the fields.

There is no misleading here.

73

JC

N4IS

 

-Original Message-

From: Topband mailto:topband-boun...@contesting.com> > On Behalf Of John Kaufmann

Sent: Monday, November 26, 2018 8:53 PM

To: topband@contesting.com  

Subject: Re: Topband: Vertical antennas aren't always best for DX

The statement that the half of a horizontal dipole's radiation is vertically

polarized is misleading and needs qualification.  There is a vertically

polarized component off the ends of the dipole but it is only of consequence

at takeoff angles approaching 90 degrees, in other words straight overhead.

I would argue that these takeoff angles are of little interest for long

distance propagation.   

At takeoff angles lower than 60 degrees or so, the total radiation pattern

of a dipole at any reasonable height becomes dominated by the horizontally

polarized component that is broadside to the dipole.   The lower the angle

or the higher the dipole, the more insignificant the vertical component

becomes. This is all verifiable in EZNEC.  If this were not true, you would

not see the well-defined radiation patterns that are produced by HF Yagi's

at higher frequencies were the radiation is horizontally polarized for

virtually all signals of interest.

73, John W1FV

-Original Message-

From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of

n...@n4is.com  

Sent: Monday, November 26, 2018 11:06 AM

To: 'Roger Kennedy'; topband@contesting.com  

Subject: Re: Topband: Vertical antennas aren't always best for DX

Roger

Every dipole or inverted V irradiate  50% of the power horizontal polarized

broadside with the wire and 50% of the power vertical polarized along the

wire. After the first refraction it does not matter. 

This is an electro-magnetic wave law. You can check that on EZENEC, it is

not a anecdote.

 

The advantage over vertical 1/4 wave antenna is efficiency.  The vertical

efficiency depends on the ground plane resistance, it is common to see

invert L with only 50 % irradiated power, the other 50% is dissipated on the

ground.

"In Theory, we know everything, but nothing works"

"In Practice, everything works, but we don't know why"

We never will fully understand the 160m band.

73's

JC

N4IS

 

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Topband: Vertical antennas aren't always best for DX

[Roger Kennedy]

Yes, but according to EZNEC, a 160m dipole at 50ft produces very little
radiation at low angles, compared to one at 150ft.

But I'm sceptical about the accuracy of EZNEC with such a low antenna, as
it's just based on theory . . . I'm not convinced it can accurately model
the real-world situation of what is actually happening with the ground
underneath the antenna.  (remember - my 160m dipole is like a 20m dipole 3ft
off the ground!)

Roger G3YRO



Sorry ,  but all antenna's on 160m are close to the ground and it is the
case, you can check by yourself using EZENEC if you don't know how to
calculate the fields.

There is no misleading here.

73
JC
N4IS
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

Re: Topband: Vertical antennas aren't always best for DX

[John Kaufmann]

In considering the *total power* radiated by any antenna, you need to look
at the 3-dimensional antenna pattern, not a 2-dimensional slice.  The total
radiated power is the 3-dimensional integration of the 3-dimensional
radiation pattern.  It is convenient to do this in spherical coordinates
because that is how we visualize 3-dimensional patterns.   In spherical
coordinates the integration applies the *smallest* weighting at elevation
angles around zenith.  Even if the dipole is low, the calculation shows that
the fraction of power that goes straight up is small compared to the total
radiated power.   This is easily understood in 3-dimensional spherical
coordinates:
https://www.khanacademy.org/math/multivariable-calculus/integrating-multivar
iable-functions/triple-integrals-a/a/triple-integrals-in-spherical-coordinat
es.

73, John W1FV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
n...@n4is.com
Sent: Tuesday, November 27, 2018 6:58 AM
To: jkaufm...@alum.mit.edu; topband@contesting.com
Subject: Re: Topband: Vertical antennas aren't always best for DX

Sorry ,  but all antenna's on 160m are close to the ground and it is the
case, you can check by yourself using EZENEC if you don't know how to
calculate the fields.

There is no misleading here.

73
JC
N4IS



-Original Message-
From: Topband  On Behalf Of John Kaufmann
Sent: Monday, November 26, 2018 8:53 PM
To: topband@contesting.com
Subject: Re: Topband: Vertical antennas aren't always best for DX

The statement that the half of a horizontal dipole's radiation is vertically
polarized is misleading and needs qualification.  There is a vertically
polarized component off the ends of the dipole but it is only of consequence
at takeoff angles approaching 90 degrees, in other words straight overhead.
I would argue that these takeoff angles are of little interest for long
distance propagation.   

At takeoff angles lower than 60 degrees or so, the total radiation pattern
of a dipole at any reasonable height becomes dominated by the horizontally
polarized component that is broadside to the dipole.   The lower the angle
or the higher the dipole, the more insignificant the vertical component
becomes. This is all verifiable in EZNEC.  If this were not true, you would
not see the well-defined radiation patterns that are produced by HF Yagi's
at higher frequencies were the radiation is horizontally polarized for
virtually all signals of interest.

73, John W1FV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
n...@n4is.com
Sent: Monday, November 26, 2018 11:06 AM
To: 'Roger Kennedy'; topband@contesting.com
Subject: Re: Topband: Vertical antennas aren't always best for DX

Roger

Every dipole or inverted V irradiate  50% of the power horizontal polarized
broadside with the wire and 50% of the power vertical polarized along the
wire. After the first refraction it does not matter. 

This is an electro-magnetic wave law. You can check that on EZENEC, it is
not a anecdote.


The advantage over vertical 1/4 wave antenna is efficiency.  The vertical
efficiency depends on the ground plane resistance, it is common to see
invert L with only 50 % irradiated power, the other 50% is dissipated on the
ground.

"In Theory, we know everything, but nothing works"

"In Practice, everything works, but we don't know why"

We never will fully understand the 160m band.

73's
JC
N4IS


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Re: Topband: Vertical antennas aren't always best for DX

[lennart.michaelsson]

This reminds me of the fine signals 3Y0X was producing on 160 back in
February 2006.
They were using a 3 el horisontal beam 4 ft above the ice...

73
Len SM7BIC

-Ursprungligt meddelande-
Från: Topband  För Roger Kennedy
Skickat: den 27 november 2018 11:39
Till: topband@contesting.com
Ämne: Topband: Vertical antennas aren't always best for DX


Very interesting reading all the comments . . .

Bear in mind that MY Dipoles have always been pretty low, around 50ft.  Also
that the British stations I have done proper comparisons with all have
decent verticals, typically at least 70ft high and over 40 quarter wave
radials. (you would recognise their callsigns)

I personally suspect that having a poor ground under such a low dipole would
cause it to have more low angle radiation than EZNEC predicts (ie the
antenna "thinks" it's higher). This seems to be born out by the fact that
people who have a Dipole that is over a radial system (for their vertical)
DOESN'T seem to work so well for DX as mine does.

So although having my own Vertical AND a Dipole to compare would be great, I
would only consider it if I could get the Dipole a long way away from the
radials. (in practice I could never get a proper set of radials out, nor
could I go high enough - I live in a very ordinary street with a
normal-sized garden, so one leg of my Dipole goes across the street!)

I do at least now have a Receiving Loop in my Loft, which is vertically
polarised. (and has a pre-amp, set to make local signals the same strength
as my Tx antenna). It's very interesting to note the difference on signals
switching between the two. Occasionally, there can be 10dB difference . . .
but MOST of the time, DX signals are exactly the same strength on both
(which supports my 2 theories)

However, based on my signal reports from DX stations, it does seem that my
low Dipoles have always worked much better than most of you guys in NA that
have tried them . . . so I wonder why that is?  Is it down to these
Geomagnetic lines? 


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Re: Topband: Vertical antennas aren't always best for DX

[n4is]

Sorry ,  but all antenna's on 160m are close to the ground and it is the
case, you can check by yourself using EZENEC if you don't know how to
calculate the fields.

There is no misleading here.

73
JC
N4IS



-Original Message-
From: Topband  On Behalf Of John Kaufmann
Sent: Monday, November 26, 2018 8:53 PM
To: topband@contesting.com
Subject: Re: Topband: Vertical antennas aren't always best for DX

The statement that the half of a horizontal dipole's radiation is vertically
polarized is misleading and needs qualification.  There is a vertically
polarized component off the ends of the dipole but it is only of consequence
at takeoff angles approaching 90 degrees, in other words straight overhead.
I would argue that these takeoff angles are of little interest for long
distance propagation.   

At takeoff angles lower than 60 degrees or so, the total radiation pattern
of a dipole at any reasonable height becomes dominated by the horizontally
polarized component that is broadside to the dipole.   The lower the angle
or the higher the dipole, the more insignificant the vertical component
becomes. This is all verifiable in EZNEC.  If this were not true, you would
not see the well-defined radiation patterns that are produced by HF Yagi's
at higher frequencies were the radiation is horizontally polarized for
virtually all signals of interest.

73, John W1FV

-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of
n...@n4is.com
Sent: Monday, November 26, 2018 11:06 AM
To: 'Roger Kennedy'; topband@contesting.com
Subject: Re: Topband: Vertical antennas aren't always best for DX

Roger

Every dipole or inverted V irradiate  50% of the power horizontal polarized
broadside with the wire and 50% of the power vertical polarized along the
wire. After the first refraction it does not matter. 

This is an electro-magnetic wave law. You can check that on EZENEC, it is
not a anecdote.


The advantage over vertical 1/4 wave antenna is efficiency.  The vertical
efficiency depends on the ground plane resistance, it is common to see
invert L with only 50 % irradiated power, the other 50% is dissipated on the
ground.

"In Theory, we know everything, but nothing works"

"In Practice, everything works, but we don't know why"

We never will fully understand the 160m band.

73's
JC
N4IS


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Topband: Vertical antennas aren't always best for DX

[Roger Kennedy]

Very interesting reading all the comments . . .

Bear in mind that MY Dipoles have always been pretty low, around 50ft.  Also
that the British stations I have done proper comparisons with all have
decent verticals, typically at least 70ft high and over 40 quarter wave
radials. (you would recognise their callsigns)

I personally suspect that having a poor ground under such a low dipole would
cause it to have more low angle radiation than EZNEC predicts (ie the
antenna "thinks" it's higher). This seems to be born out by the fact that
people who have a Dipole that is over a radial system (for their vertical)
DOESN'T seem to work so well for DX as mine does.

So although having my own Vertical AND a Dipole to compare would be great, I
would only consider it if I could get the Dipole a long way away from the
radials. (in practice I could never get a proper set of radials out, nor
could I go high enough - I live in a very ordinary street with a
normal-sized garden, so one leg of my Dipole goes across the street!)

I do at least now have a Receiving Loop in my Loft, which is vertically
polarised. (and has a pre-amp, set to make local signals the same strength
as my Tx antenna). It's very interesting to note the difference on signals
switching between the two. Occasionally, there can be 10dB difference . . .
but MOST of the time, DX signals are exactly the same strength on both
(which supports my 2 theories)

However, based on my signal reports from DX stations, it does seem that my
low Dipoles have always worked much better than most of you guys in NA that
have tried them . . . so I wonder why that is?  Is it down to these
Geomagnetic lines? 


_
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