A Low-budget 4-square Vertical System for 75/80 Meters

Bob Bruner, WØEK and XYL Debbie, KBØSIL, live on 40 acres of rolling countryside near Albany, MN, where they enjoy the tranquility of country living. While Bob keeps busy chasing DX, Debbie stays busy with her hobby: breeding and showing Persian cats. Visit her website to see some of the “kids”, close up. www.deebows-persians.com

Like many that start out chasing DX on the higher frequencies, Bob soon got hooked on the low bands. Early-on, he had beverage antennas, so his receive setup was a winner. However, his performance suffered on transmit. Dipoles and inverted Vs at 50 feet simply were not getting the job done. So, his dream of having a gain antenna system on 75/80 meters began to evolve.

The first phase started when Elvin, JA3CZY, came to stay with Bob, while Elvin was stateside on vacation. Bob put Elvin to work, helping him put the support posts in the ground. And, as the months passed, more work and fine tuning was done on plans for the system.

Finally, on a beautiful sunny day in late fall, it all came together. On November 11th, after months of planning and preparation, his 4-square vertical system for 75/80 meters became reality. With the help of KBØSIL, KØIEA, KØJUH, and a “cherry picker” rig, the 4-square system went up, and was put on the air for the first time. And, amazingly, the system performed flawlessly on the initial key down test.

by Jim Junkert, KØJUH

The SWR was flat across the entire band! From 3500 to 4000 the SWR did not exceed 1.2 to 1. The system is switchable in four directions: NW, NE, SE, and SW. Early tests indicate a three to five S-unit advantage on receive over Bob’s inverted V. The difference is even greater on transmit. Front to back is running around 25 to 30 db.

If you’re serious about duplicating Bob’s effort, the following materials list will give you what is required. Keep in mind that the more you’re willing to horse trade, homebrew, and scrounge around for material, the more dollars you will save. The total cost of this system came in at less than $1100.

MATERIALS LIST

4 Verticals: Constructed from two 30-foot sections of 4” diameter aluminum irrigation pipe. At the top is a 4-foot section of 3” diameter pipe, which can be adjusted to vary the overall length for tuning purposes. The best SWR results were obtained with the total length set at 63 feet.

Vertical Support Posts: Four 12-foot 6x6 posts sunk 4 feet into the ground, and spaced 70 feet apart, in a square configuration. The spacing is greater than a quarter wave, in order to maximize forward gain.

14

Ground Radials: 40 quarter wave radials (14 guage) for each vertical. Total wire = 11,200 feet.

Radial Plates: 4, total. These are Bob’s own design from 1/4 inch stainless steel plate. Each plate has sixty terminals to connect the radials to and one PL 239 coax connector.

Phasing Box: This is the same DX Engineering box that made the trip to Heard Island and back in 1997 and Bob purchased it in 1998 from WØGJ. It’s been in storage, ever since. It was resurrected for this project, along with the original 75-ohm coax phasing lines.

3/16” Dacron Guy Rope: Each vertical is guyed 3 times: at 27 ft, 37 ft, and 47 ft. - a total of nine guy ropes per vertical. The ropes tie off to 6-foot steel fence posts (from Fleet Farm), spaced at 120 degree intervals around each vertical. Total guy rope = 1,400 feet.

And last, but not least, a miscellaneous assortment of stainless steel nuts, bolts, terminals, wire, etc.

Bob extends his thanks to a host of people for their advice and help on this project. KØKX, K1ZM, WØGJ, ON4UN, and K7EM, to mention a few. And, we can’t forget the construction crew: XYL, Debbie, KBØSIL, Elvin, JA3CZY, Dave, KØIEA, Jim, KØJUH, Toby the Yellow Lab, and Red the friendliest cat on earth.

If anyone has comments or questions on this 4- square system, please feel free to contact Bob Bruner at wØek@upstel.net. Also, visit Bob’s website at http://www.w0ek.com/ for more information on the system.