= = = "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
..