Information on Four-Square Phased Arrays

Dear Amateur:

Thank you for your interest in the Comtek ACB-4 series of Hybrid couplers for Four-Square arrays.

The Four-Square was developed in the 1980's by Fred Collins, W1FC and Dana Atchley, W1CF (SK), and in conjunction with Steve Davis, K1PEK, formed ColAtchCo. Fred and Dana jointly developed the hybrid for proper phasing. ColAtchCo offered complete systems, including verticals, radial wire, control cable and phasing lines.

In the late 1980's, Comtek took Mr. Collins' hybrid further by adding a second toroid, to replace the 180 degree coax and phase correction coax cables. The only coax required are four (4) electrical quarter wave foam 75 ohm and the 50 or 75 ohm line from the transmitter.

A Four-Square consists of four verticals spaced one quarter (1/4w) wavelength apart (feedpoints quarter wave apart for 1/2 wave dipole arrays) with the hybrid mounted in the center of the array. The directivity is across the diagonals, selectable in four directions.

Since new ownership of the company in 1993, numerous improvements have been made to both the power supply/switch control and the hybrid relay unit. The Instruction Manual numbers twenty-five pages with schematics.

Although the three "Low Bands" of 40, 80, and 160 meters are the most popular models sold, we have seen an increase in 20 meter models for those unable to install a tri-band beam on a fifty (50') tower during the past two years. ACB-20 customers report good results using the array on 17 meters in addition to the excellent 20 meter performance.

Comtek Systems Hybrids are in use world wide by serious contesters. DX'ers and the serious ham in general. Our hybrids with properly installed arrays offer 20 dB F/B and up to 5dB gain, at a lower cost than most low band beams at proper heights.