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Old October 19th 04, 09:33 PM
Brian
 
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Default significance of feedline orientation

The antenna I had up before I moved was end-fed at the 9:1 transformer,
ground point. Would moving the feed-point, ground, transformer closer
towards the middle of the antenna have any negative effects, or effects at
all? My new residence would accomodate this orientation better. By the way,
I found a cool shop called Communication Headquarters right down the street
that has a ton of radio gear, yay!

-Brian


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Old October 20th 04, 12:06 PM
RHF
 
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Default

= = = "Brian" wrote in message
= = = ink.net...

The antenna I had up before I moved was end-fed at the 9:1 transformer,
ground point. Would moving the feed-point, ground, transformer closer
towards the middle of the antenna have any negative effects, or effects at
all? My new residence would accomodate this orientation better. By the way,
I found a cool shop called Communication Headquarters right down the street
that has a ton of radio gear, yay!

-Brian


BRIAN,

I guess what you are talking (writing) about is the Placement
of the Feed-in-Line of the Antenna. Originally your Feed-in-Line
(Coax Cable) was at One End of your Antenna. Now you are asking
about the possibility of placing the Feed-in-Line more toward
the Center of the Antenna.

This type of Center-Fed Antenna is called a Dipole.
- A Compilation of Dipole Antennas
http://groups.yahoo.com/group/Shortw...na/message/774

Another type of Off-Center-Fed Antenna is called the Windom.
- Windom Antenna 160M - 10M = July 2004 Monthly Antenna Image
http://groups.yahoo.com/group/Shortw...a/message/1085
- My Favorite Multi-Band Antenna - The "WINDOM"
- - by G. E. "Buck" Rogers Sr [K4ABT]
This is an 'improved' Windom that is set-up as an Off-Center-Fed
Dipole with a Balun and Coax Feed-in-Line.
- A Six-Band, HF Windom Antenna - by K3MT
http://users.erols.com/k3mt/windom/windom.htm
- Eight Bands On One Coax - The Windom Antenna - by KH2D
http://kh2d.net/windom.cfm
- Coaxially Fed Windom Antenna
http://salsawaves.com/antennas/windom/
http://www.qsl.net/sv1bsx/windom/windom.html
- The Windom Antenna - by R.J.Edwards [G4FGQ]
http://www.smeter.net/antennas/windom2.php
- Off-Center Feed - The "Windom" Antenna - by Bill Buchholz [K8SYH]
http://www.k4lrg.org/Projects/Windom_K8SYH.html

QUESTION: The Windom or the Dipole ?
- Windom -vice- Dipole which is the better SWL Antenna ? ? ?
http://groups.yahoo.com/group/Shortw...nna/message/80
- A Second Look = Windom -=V=- Dipole = Which is the better SWL Antenna
http://groups.yahoo.com/group/Shortw...na/message/588

* The ORIGINAL Windom Antenna:
A single 'bare' Wire Antenna Element that is Fed at a Point that
is 36% to 64% of the Length of the Wire. The Feed-in-Line is
also a simple Insulated Wire.

* The Improved "Low Noise" Windom Antenna:
A single 'bare' Wire Antenna Element that is Fed at a Point that
is 36% to 64% of the Length of the Wire. A UnUn type Matching
Transformer is used to 'couple' the Wire Antenna Element to the
Coax Cable. The Feed-in-Line is Coax Cable.

* The "Dipole" Windom Antenna:
Two un-equal 'bare' Wire Antenna Elements that are Fed at a Point
that has the shorter wire 36% and the longer wire 64% of the
Length of the Available Space. A Balun type Matching Transformer
is used to 'couple' the Wire Antenna Element to the Coax Cable.
The Feed-in-Line is Coax Cable.

* The "G5RV" Windom Antenna:
Two un-equal 'bare' Wire Antenna Elements that are Fed at a Point
that has the shorter wire 36% and the longer wire 64% of the
Length of the Available Space. A Ladder Line is used as a
Vertical Antenna Element to the Ground. At the Ground a Balun
type Matching Transformer is used to 'couple' the Vertical Antenna
Element to the Coax Cable. The Feed-in-Line is Coax Cable.

SUGGESTION: Since you have an Antenna Wire Element; 9:1 Matching
Transformer; Coax Cable; and Ground Rod from your old Antenna
installation. You may wish to consider a basic Windom Antenna
with a Single Wire "Off-Center-Fed Antenna Element to fill your
'available space'. Measure the Available 'space' for your Wire
Antenna Element and Mark-Off 36% of that distance as the Location
of your Feed-Point. Run your Coax Cable up to your Matching
Transformer at this Feed-Point.

iane ~ RHF
..
..
Some Say: On A Clear Day You Can See Forever.
http://groups.yahoo.com/group/Shortw...na/message/502
I BELIEVE: On A Clear Night...
You Can Hear Forever and Beyond, The Beyond !
..
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Old October 20th 04, 02:04 PM
Brian
 
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BRIAN,

I guess what you are talking (writing) about is the Placement
of the Feed-in-Line of the Antenna. Originally your Feed-in-Line
(Coax Cable) was at One End of your Antenna. Now you are asking
about the possibility of placing the Feed-in-Line more toward
the Center of the Antenna.


Yes, that is correct and thank you very much for the information. I had not
heard of the Windom antenna before, but will do some research on it. Sounds
like what I am going for though. Thanks again, 73.

-Brian


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Old October 21st 04, 12:09 AM
RHF
 
Posts: n/a
Default

= = = "Brian" wrote in message
= = = ink.net...
BRIAN,

I guess what you are talking (writing) about is the Placement
of the Feed-in-Line of the Antenna. Originally your Feed-in-Line
(Coax Cable) was at One End of your Antenna. Now you are asking
about the possibility of placing the Feed-in-Line more toward
the Center of the Antenna.


Yes, that is correct and thank you very much for the information. I had not
heard of the Windom antenna before, but will do some research on it. Sounds
like what I am going for though. Thanks again, 73.

-Brian


BRAIN,

If you are interested in a ready-made Windom Antenna then
check-out the "Carolina Windom".
http://www.radioworks.com/ccwcover.html
- Does the Vertical Radiator really work ?
http://www.radioworks.com/ccwpat.html
- What make the Carolina Windom so good ?
http://www.radioworks.com/ccwsogood.html

Also take a look at these two other ready-made Windom Antennas:
* Classic Windom "No-Tune" Multi-band Antenna - by Antennas & More
http://www.antennasmore.com/windom.htm
* OFF-CENTER FED "CLASSIC WINDOM WIRE" 80-10 METERS - by KK4TR
http://kk4tr.tripod.com/index-10.html
- Windon with a Balun and Coax Feed-in-Line
http://kk4tr.tripod.com/classic_windom.jpg
- Windom with Balun, Ladder Line Vertical and Coax Cable Feed-in-Line
http://kk4tr.tripod.com/kk4tr_windom.jpg

Another ready-made Windom Antenna is the RF Systems "Mini-Windom"
Antenna which is only 16 Feet Long with a 16 Feet Feed-in-Line.
http://www.universal-radio.com/catalog/sw_ant/3575.html
http://www.rys.nl/rfsystems2.html


iane ~ RHF
..
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Old October 21st 04, 09:45 AM
starman
 
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Default

Brian wrote:

The antenna I had up before I moved was end-fed at the 9:1 transformer,
ground point. Would moving the feed-point, ground, transformer closer
towards the middle of the antenna have any negative effects, or effects at
all? My new residence would accomodate this orientation better. By the way,
I found a cool shop called Communication Headquarters right down the street
that has a ton of radio gear, yay!

-Brian


As you move along the wire the impedance changes. Moving the feedpoint
to some other location could result your 9:1 balun being less efficient
(mismatched). There are antennas which use a feedline connected to some
point along the wire instead of the end but you have to make the
connection at a specifc location, not just anywhere. The 'Windom' is one
of these types. The following website shows the design of a basic Windom
antenna. Note that the balun is 4:1 instead of your 9:1 for the end fed
wire. This is because the impedance at the connection point for a Windom
is lower than the end of a random wire or inverted-L.

http://www.packetradio.com/windom.htm


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Old October 21st 04, 02:54 PM
Brian
 
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As you move along the wire the impedance changes. Moving the feedpoint
to some other location could result your 9:1 balun being less efficient
(mismatched). There are antennas which use a feedline connected to some
point along the wire instead of the end but you have to make the
connection at a specifc location, not just anywhere. The 'Windom' is one
of these types. The following website shows the design of a basic Windom
antenna. Note that the balun is 4:1 instead of your 9:1 for the end fed
wire. This is because the impedance at the connection point for a Windom
is lower than the end of a random wire or inverted-L.

http://www.packetradio.com/windom.htm


Thanks for the info. After doing research on the Windom antenna I gathered
it was going to be a little more involved than I expected, and I'm not sure
if it will be as effective for receiving. I'm leaning towards sticking with
the random wire and just getting more coax to reach the feed point instead
of bringing the lead-in closer.

-Brian


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Old October 22nd 04, 01:43 AM
RHF
 
Posts: n/a
Default

= = = "Brian" wrote in message
= = = link.net...
As you move along the wire the impedance changes. Moving the feedpoint
to some other location could result your 9:1 balun being less efficient
(mismatched). There are antennas which use a feedline connected to some
point along the wire instead of the end but you have to make the
connection at a specifc location, not just anywhere. The 'Windom' is one
of these types. The following website shows the design of a basic Windom
antenna. Note that the balun is 4:1 instead of your 9:1 for the end fed
wire. This is because the impedance at the connection point for a Windom
is lower than the end of a random wire or inverted-L.

http://www.packetradio.com/windom.htm


Thanks for the info. After doing research on the Windom antenna I gathered
it was going to be a little more involved than I expected, and I'm not sure
if it will be as effective for receiving. I'm leaning towards sticking with
the random wire and just getting more coax to reach the feed point instead
of bringing the lead-in closer.

-Brian



BRAIN,

If you configure your Windom as an Off-Center-Fed Dipole Antenna.
(Two Wires with the Balun's Primary between them.)
- Then the 4:1 Balun will work well.

However, 'if' you configure your Windom as an Off-Center-Fed
Longwire (Random Wire) Antenna. (A Single Wire with one Lead
of the UnUn's Primary connected to the 38%/62% Mid-Point.)
- Then the 9:1 UnUn (MLB) will work well.

SIZING YOUR WINDOM ANTENNA:

Measure the Distance that is available for you to 'suspend'
your Windom's Wire Antenna Element.
Calculate the 38% 'short' Arm and the 62% 'Long' Arm.

For the Dipole 'configured' Type Windom.
If you have between 65 to 80 Feet 'available' try:
* Cut the Long-Arm of this Antenna for the 49 Meter SW Band
= Long-Arm's Length = 38.5 Feet
= Long-Arm (38.5) / Total Length (62.7) = 61.5%
* Cut the Short-Arm of this Antenna for the 31 Meter SW Band
= Short-Arm's Length = 24.1 Feet
= Short-Arm (24.1) / Total Length (62.7) = 38.5%
Total Length of this Windom Antenna would be 62.7 Feet.

For the Longwire 'configured' Type Windom.
If you have between 110 to 120 Feet 'available' try:
* Cut the Long-Arm of this Antenna for the 41 Meter SW Band
= Long-Arm's Length = 69 Feet
= Long-Arm (69) / Total Length (106) = 65%
* Cut the Short-Arm of this Antenna for the 22 Meter SW Band
= Short-Arm's Length = 37 Feet
= Short-Arm (37) / Total Length (106) = 35%
Total Length of this Windom Antenna would be 106 Feet.

FWIW: I 'like' the Dipole 'configured' Type Windom with a
300 Ohm Twin Lead or 450 Ohm Ladder Line Vertical Feed-in-Line.
Using the above set-of-numbers for the Dipole 'configured'
Windom Antenna.
- Mount/Rig the Antenna at a Height of 24-26 Feet.
- Run the Ladder Line Straight Down Vertically.
- Install a Ground Rod at this point in the Ground 'directly'
under the Ladder Line.
- Mount your Balun 'directly' on the Ground Rod.
- Run/Route your Coax Cable from the 'junction' of the Ground
Rod and Ladder Line and to your Radios/Shack.
- Connect the Ground Rod/Wire; Ladder Line and Coax Cable to
the Balun.

iane ~ RHF
..
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