The triple 4-SQUARE Project

Spring 2004. The 4-square project was lingering in my mind already for a couple of years. Being back home for a longer while, this was the time to go ahead and start working on the long-term 4-square project.

Long-term, because I want to suspend the verticals from trees. And trees need time to grow. I guess in a couple of years the trees for the 40m 4-square will be tall enough, the 80m and 160m 4-squares will take a bit longer ;-

The preparatory work is finished. Cutting the 12 quarter wave 75 Ohm coaxial feed lines to exact lengths and put connectors on them, prepare the 12 small cabinets where the verticals will be attached to, digging a couple of hundreds of meters of one meter deep trenches, etc...

As one can see on the photographs, the 40m 4-square will be centered in the 80m one, which will be centered in the 160m 4-square. Hence the 'Triple 4-square'. Can't wait for the trees to grow....

Karel ON5TN was so eager to do some tests on 4-squares, I decided to buy aluminum and prepare the 40m 4-square for him. On October 3d 2005 - a beautiful autumn day with a partial solar eclipse - we did the following tests with a 4-channel Oscilloscope. A must see !

Click on the following photographs to see the full size pictures of the triple 4-square preparation. Enjoy !

The hard work is finished, let the trees grow, let them grow !
This is an aerial overview with the layout of the triple 4-square clearly visible
On the right hand side foreground, one can notice the K9AY array. At the back of the field one can see the triple 4-square array
Preparation. Preparing four quarter wave 75 Ohm feed lines for 40m, four for 80m and four for 160m. Trimming to correct lengths and putting connectors on takes a while. These feed lines go from the central hybrid coupler to each of the verticals.
Also visible in the back, upright, is 135m of 7/8" hardline 50 Ohm coaxial cable
The finished feed line goes inside red plastic tubing. Note the white pull-cable, which can be used at any time to pull in extra cables for relay switching etc...
Four 160m feedlines are finished
Preparing 12 cabinets which will be placed at each vertical
Twelve cabinets painted and finished
A trench 135m long, one meter deep, goes from the tower to the central main cabinet of the triple 4-square. Inside goes 7/8" hardline 50 Ohm cable, a 30 conductor multi-purpose cable, and a 220V line
Already looking for DX with the 40m feed lines
All twelve feed lines ready to go below surface. The trench from the tower to the center of the 4-squares is finished
40m and 80m trenches for SW direction are finished, and here we are digging the 160m feed line trench
This neat little machine is supposed to dig in straight lines, so we needed some horsepower to bend the curves

NW direction feed lines in place

After some 500m of digging (at the same time a Beverage coaxial cable was put in a 170m trench), we've reached the finish line
This is Karel ON5TN, who likes electronics, DX-ing, going on DX-peditions (XU and 6W so far), and who is not afraid of making his hands dirty.
Here he's working on the spot where the central main cabinet will come, playing with the feed lines...
The 40m feed line is visible coming out of the ground, in the direction of the central cabinet
This is one of the feed lines surfacing the earth, nicely labelled thanks to Karel ON5TN
Beyond the open cabinet one can see the 40/80/160m 'trees' and the surfacing feed lines in NW direction
Inside the cabinet, we got plenty of time ahead to arrange the cabling and put the hybrid couplers inside
The twelve smaller cabinets for the individual 4-square verticals, together with the twelve ground rods to which they will be attached.
Once the verticals will be suspended, ground radials will be attached to the ground rods
Attaching a feed line cabinet to the ground rod
Inside a feed line cabinet, lots of space to play around with matching networks
Each feed line cabinet and its tree is protected with high voltage wires around it, to prevent the summer cattle to damage the construction
40-80-160m cabinets, trees and high tension protection in NW direction
Connecting the 75 Ohm feed line to each cabinet and making it waterproof
Final touch of painting
No worries, everything is nicely labelled inside the central main cabinet

Send Comments and Queries to: