Thanks - I guess I should have added some background

I've tried top loading and it works but is unwieldy. I'm working on an
variant of the St Louis vertical which does use a loading coil (at the
bottom) Since this antenna starts with the assumption that a light weight
portable mast will be used, a top load solution puts too much stress on the
weak top whip of the pole. For example, the calculation of a top load
cylinder is about 13" long by13" wide. I built on out of light weight
aluminum window screen and it worked but dragged the top down.

By contrast, using a length of 450 ohm ladder line, I hoped to build an
easily transportable antenna with a better SWR range than the SLV. I'm
iterating on the solution but still looking for some analytic approach.

Tom
W2TER

Back to my
"Yuri Blanarovich" wrote in message
...

Does anyone have a good source for calculating the length of linear loads
for a shortened 40 meter Vertical? I'm experimenting with a 20' vertical
and a pair of 10' parallel lines moved the resonant point near the 7 Mhz
band. Any suggestions?



More elegant and efficient solution is to use loading coil placed abour
2/3 up
the radiator. Best is to use top loading with hat or wire.

Yuri, K3BU