Dave says:

I recently re-constructed my 40 meter four square array using four full-size 40 meter ground plane antennas constructed from #12 copper wire.  The antenna base is elevated 42 feet above the ground.  I retuned the array to a lower frequency (because the short-wave stations left) and I am now using coax RF choke baluns at the feed points instead of ferrite beads.  The beads can cause several problems, namely power loss, phase shift, permanently saturated by close lighting strikes (BAD!!)...etc.  The coax RF choke baluns eleminate RF currents from flowing on the outside of the coax cable.  This assures the ground plane is doing the radiating and not the feedline.  This also help to prevent array pattern distortion and increases the F/B ratio.  The coax RF choke baluns are constructed of RG-6 coax, 13 turns, in a 4 inch diameter....single layer....DON'T "bunch the turns" as this will eliminate the choking effect.  However, after several antenna tests, the ground mounted system seems to outperform the ground planes by about 8 db to 15 db as far as F/B is concerned.  However, the gain of both arrays seems to be about the same, approximately 6 to 8 db over my reference antennas.  I am using a Comtek phasing system built by Jim Miller, K4SQR, for both my 40m and 80m four square arrays.

1.     2.     3.     4.

1.     One of the feed points, only two radial connections shown for clarity.  Of course, it's all weatherproofed when it's installed - blue sky in pics 2 & 3 but look at the clouds in 4!!
2, 3 & 4     Views looking upward towards the 40m 4-square, the coax choke baluns can clearly be seen.