Topband: Detuning shunt fed towers

[John Harden, D.M.D.]

I have a 100 ft 45G, shunt fed tower with stacked monobanders for 80 -10 
meters. This includes a 24 ft mast with 12 feet out the tower top. I do 
not even worry about detuning it.
The shunt (4 wire) cage only goes up to 30 feet due to monobanders down 
to about 35 feet. It requires a 2000 pfd vacuum variable in series and a 
1000 pfd vacuum variable to ground (Omega match) to resonate the system. 
The series capacitor is motor driven by a 1 RPM, 12 VDC motor. The SWR 
remains flat over the band measured at the match and in the shack. I 
have right at 40 radials on ground. At this point the curve becomes 
asymptotic..........

With an Amphenol Type "HN" connector there is never any flashover. 
SO-239's did not cut it. Type "N" is even worse.

My Hi-Z 4-8 PRO RX antenna is over 100 feet away and there appears to be 
little interaction. If you do the math there should be interaction but 
there is so little "real" interaction that I simply disregard it.... The 
guys at Hi-Z will tell you there is very little difference between the 
4-8 PRO and the 8 el array that is in a 200 ft diameter circle. They 
have both up. The decrease in beam width between the two is 
inconsequential to me....

I can now hear about anything that is on compared to others in my area, 
and can work it quickly if I can hear it. The Hi-Z array is that 
good.... The waters of the sea have parted for me on top band.

73,

John, W4NU
K4JAG (1959 to 1998)