Tower 1
Tower 1 is 97 feet of Rohn 25. This tower has a homebrew insulated base
using three large ceramic insulators. They are about 8-inches diameter and a bit of overkill -- one would have done the job.
To test their load I drove over an extra one that was cracked with my Jeep several times with no damage done.
This tower is series-fed as a vertical on 160 meters. For top loading, there
is a 4-element 6-meter yagi, a recently added modified HyGain 105BA for 10 meters, a long 220-mHz yagi for the PacketCluster
node backbone link, and a couple of phased 2-meter verticals for the PacketCluster user frequency. A small LC network at the
base brings the tower into resonance around 1830 kHz.
A 1/4 wave wire for 40 meters is hung off the tower and works quite well
as a backup to the 40m beam on another tower.
Large coils of coax or small hardline are wound on 6-inch PVC forms to serve
as RF chokes on the feedlines and rotor cable going up the tower. These are placed right at the base. I could have eliminated
these by shunt-feeding the tower but I wanted to be able to easily "float" the tower to enable tuning of the parasitic elements.
Thanks to Tom, W8JI, for the RF choke idea.
Sloping T-shaped parasitic elements for 160 meters are hung off the top
of the tower, supported by rope catenaries. These are spaced out 66 feet to the NE, SE, SW and NW, giving us a switchable
3-element parastic array in four directions. This project is still under construction -- so far I have the NE/SW elements
and the SE element in place. For more info on this K3LR array see ON4UN's Low Band Antennas book.
An extra director (90 feet of Rohn 25, base loaded) toward Europe
gives us four elements in that direction.
There are 120 radials coming off the center driven element, and
120 radials coming off each of the parastic elements. These are 1/4 wave radials or as long as it takes to meet buss wires
midway between elements.Radials are mostly No. 12 insulated THHN stranded wire obtained from a local scrap yard. Some are
No. 19 enameled wire.
The tower is located in the middle of a small grove of about 20 loblolly
pine trees that are about 70 feet tall. Guys are a mix of Phillystran and EHS steel with insulators.
Tower 2
Tower 2 is 97 feet of Rohn 45. This holds a stack of Hy-Gain 204BA 4-element
20-meter yagis at 33, 65 and 98 feet. Only the top one rotates (on a Tailtwister rotor); the lower two are fixed on Europe.
A relay box at the base of the tower allows remote selection of any combination of the antennas.
Tower 3
Tower 3 is 97 feet of Rohn 25. This holds two Wilson 15-meter yagis, model
415-M. These are four elements on a 17-foot boom. They are placed at 98 feet and 65 feet,.
An inverted Vee for 160 meters hangs from 95 feet.
Tower 4
Tower 4 is Rohn 55, installed in the winter of 2004-2005, and has a HyGain Discoverer
7-3 three element yagi on top, with plans for a second one lower down to be a stack..
Tower 5
Tower 5 is Rohn 25, offering an additional director toward Europe.
.
Tower 6
Tower 6 is 64 feet of Rohn 25 sitting on insulators, serving as a driven element for an 80 meter
parasitic array. Still under construction.
Other antennas
A rope catenary at 80 feet between Tower 1 and Tower 2 supports a 2-element delta loop parasitic
array for 80 meters, switchable NE/SW.
Numerous Beverage antennas for receiving are described on another page.
