I was reading in an old 1944 U miliary manual - TM 11 - 314 Antennas and
Antenna Systems a good deal of material on top loaded verticals for 1 - 2 mhz.
The author writes of several forms of capacity hats - disks, spheres and
cylinders and notes a wire or skeletal form has nearly same effect as a solid
form. There is included an interesting table of capacitance values for the 3
forms and the cylinder form appears to most dense. (i.e. a 36 inch diameter
cylinder has 70 uufd while a 36" diameter dish has 50 and the delta increases
with size).
Aside from that in Bill Orr's last book - HF Antenna Book - it shows a top
loaded vertical by KY3F which uses a cylinder form constructed from plaster
wire mesh - seems fairly simple and maybe easier to deal with in a tight space
than the disk.
Has anyone here made a cylinder form capacity hat?
73 Pete W2PM
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