Topband: 4 square maintenance

[Ron Feutz]

Topbanders,

My 4 square elements all have differing feed point impedances, measured 
with the MFJ 259B.
These range from R=16,X=4 to R=27,X=7.  The ground system is substantially 
the same for each element, with 72 radials, approx. 125' for the ones 
running "out" of the array, and the ones running "in" soldered to buss 
wires bisecting the array.  All solder joints are OK and DC resistance from 
the coax shields to the ground system is nil. The differences have to be in 
the ground conductivity under the individual elements.  The element with 
the lowest impedance is adjacent to the creek with a water table a few 
inches down, and the others are back in the woods a bit, on much drier soil.

Impedances measured at the center of the array range from R=146,X=30 to 
R=84,X=13. This is a substantial variation as  seen by the ComTek 
box.  Directivity seems to be OK, but my observations are highly subjective 
and based on limited experience.  I added radials until additional ones had 
virtually no effect on the feed point impedance of the elements.  Any ideas 
on how this situation may be affecting the performance of the array, and 
any suggestions on how to equalize the impedances?

Ron - WA9IRV