[Lowfer] coil design validation

[Lyle Koehler]

I can see only 4 radials in the picture. Adding the other radials and the
inner wires to the model is messy, and I'll leave that as an exercise to the
student :-) Seriously, closely spaced wires do not add much capacitance to
the top hat, so a simpler "skeleton" model is usually adequate. If you
actually need less inductance than the model predicts, that's fine. It's
usually easier to tap down on the coil than to add turns.

Using the attached model, I come up with a required inductance of about 7.8
mH. There will be some added capacitance because of the PVC pipe, but there
is no easy way to estimate its effect.

Lyle

LowFER antenna with 4-radial top hat; variable height and hat diameter
Ground Mounted
0.185 MHz
10 copper wires, feet
Hmax = 34
R = 4
H = Hmax - R ; height of top hat
HL = 1  ; height of loading coil above ground

1   0  0  0   0  0  HL  #22  ; wire from base to coil
1   0  0  HL  0  0  H   #22 ; wire from coil to top hat

1   0  0  H   R  0  H   .3" ; the next 4 wires are top hat radials
1   0  0  H   0  R  H   .3"
1   0  0  H  -R  0  H   .3"
1   0  0  H   0 -R  H   .3"

1   R  0  H   0  R  H   #22 ; the next 4 wires are the top hat "skirt"
1   0  R  H  -R  0  H   #22
1  -R  0  H   0 -R  H   #22
1   0 -R  H   R  0  H   #22

1 source
Wire 1, end2