G4ATA - Homebrew 40m 4-square

In late 2013 I really missed my full size 4-square for 80m that I had for 2 years, 2008 - 2010...or, more specifically, I missed it's awesome performance.  In 2010 I moved to a much smaller QTH that had a typically British garden....ie tiny!  In 2013 my XYL and I bought a small camper van and I thought that it could also serve as a mobile shack.  I had found a ham friendly camp site in North Norfolk and visited the site in late 2013 with a pair of phased verticals for 40m for the CQ WW SSB contest.  The phased pair worked very well using simple Christman phasing but my thoughts turned to the performance of a 4-square.

 I came across the printed circuit board for a hybrid phasing system for the 4-square on the SJ2W web site and decided that I would build my own.  The quality of the board is first class and I have since heard of many others having used the same board.  As of May 2026 they are still available here.

If you look at the SJ2W 4-sq PCB web page you will find other useful links including this to TK5EP's site.

I also built my own switch box to include a power meter showing power going into the dump load.

The vertical antennas were made from 3mm PVC coated wire attached to the top of 12m Spiderbeam poles.  This made the feed point approximately 2m above ground and I used 2 x elevated radials at the same height on each vertical.

During testing DX contacts regularly reported front to back differences of 25dB or more.  The whole array worked very well for me in several contests and is still operational from time to time at Finningley ARS.

Here are a few photos......

    SJ2W 4-square hybrid PCB .....outstanding quality


    Parts required .....

    Board built and being tested ....

    Board boxed....

    Completed Hybrid phasing system showing input connection! ......

    Hybrid dumpload and RF detector......

    Completed switch box and dump load power meter.....


    The full 4-square including 12m Spiderbeam poles for antenna support, antenna wire & radials, feed lines, phasing and switching system......

    40m 4-square at morning grey line.