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MINI HORIZONTAL "V" 2 ELEMENT "HAMSTICK" 20M BEAM.
by Russ Wilson, VE6VK

Material Required:
4ea 20M "Hamsticks"
1 inch diameter boom 4 ft 6 inches long.
1 aluminuum mounting bracket driven element.
1 aluminum mounting bracket reflector.
4 insulated CB mounting kits 3/8" by 24 TPI (2 can be un-insulated for reflector.
Wire for hairpin match. 14 gauge electrical wire with insulation removed.
Coaxial balun 12.5 ft RG58 wound on a 1-1/4 inch white PVC 8 inches long.
Bolts, nuts, lock washers for mounting.

CONSTRUCTION:

Two aluminum brackets are made out of scrap aluminum 1/16 inch thick or a little heavier if desired. The brackets are bent into shape as per the photographs to allow element kits to be mounted so the elements are at 90 degrees from one another.
At 15 ft off the ground, measurements were made of the Driven element using an electrical 1/2 wave length of RG58 as a 1:1 transformer. Using the antenna analyzer from the ground the following measurements were noted.
Impedance 25 ohms
SWR 2:1
The antenna was resonated to 14250 Khz.

A hairpin match was made using #14 gauge electrical wire with insulation removed. Two lengths 18 inches long are required. (See Arrl Antenna Book for more on hairpin matching)
The two wires have solder lugs placed on them at one end. These ends are connected to each mounting kit terminal for the Driven Element. The wires are spaced 1-7/8 inches from each other and are arranged so they are approximately 1 inch above the boom. See photographs for details below.
A couple of wood or plastic spacers are used to keep the wires separated. Also a piece of 3/8 inch thick plastic is mounted on the boom, 2 holes drilled for the wires to pass through for extra support. After the hairpin is mounted and a temporary shorting bar placed across the hairpin, the antenna is placed in its original position and further readings taken, adjusting the sliding short across the hairpin, until the impedance of 50 ohms is reached. A little juggling of the whips to bring the driven element back to 14250 Khz is necessary. After a few minutes of testing and adjustment of the hairpin short and the whips, the resonant frequency of 14250 Khz is reached and the impedance reads 50 ohms. The wire short on the hairpin can be permanently soldered.

Measure the length of the whip on the driven element, multiply this by 6% and add this to the length of each driven element whip. In my case it was 38.5 inches. 2.3 inches was added to each reflector whip. The boom length was experimented with and the length shown seemed to be optimum for the short boom. The reason for the resonant frequency chosen was my own personal preference as I do quite a lot of operating for IOTA 14260. If you wish to operate CW or any other preferred frequency you can choose by figuring out the frequency response of the beam is approximately 200Khz. The photographs should assist in figuring out the brackets etc. The actual measurements from tip of whip of each half element to boom.

Driven 1/2 element = 86.625 inches (220.0 Cm)
Reflector 1/2 element = 91.75 inches (233.0 Cm)
This is using the regular Lakeview Hamsticks.
The PHF type are much better and you do not have to readjust or mark the whips.


I worked XZ7A on CW with the beam and 80 watts, so apparently it works.
A frequency run and measured SWR is as follows:

14100      2.5:1
14130      1.5:1
14140      1.3:1
14150      1.2:1
14165         1:1
14202         1:1
14250         1:1
14300      1.1:1
14350      1.4:1


 


The finished product!


The not so "Ugly" balun



Note the 90 degree angle between element attachment mounts
and the 45 degree angle to the boom of the driven and reflector elements!
 



Pictures above showing driven element detail
with hairpin match attached and insulators mounted on boom

Many thanks to Russ, VE6VK for allowing us to share his project with all!
Russ not only is a fine antenna builder, ask him how to catch a fish!
Email Russ here for questions

 







  

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