Gents,
Here is an online coil calculator (K6STI) that is handy for those loading
coils. It is interesting to see the effect of different coil form materials.
For example, the top loading coil for my 38 foot vertical uses a PVC form.
Although this would appear to be a lossy material the form accounts for only
16% of the total loss. The Q is 340 for this close-spaced coil. This was a
lot easier to implement than an air-core coil since the coil form supports a
large top hat. I was also looking for a form that can be obtained anywhere as
this vertical project will be turned into an article and I like to make it
easy for everyone to find parts.
<A
HREF="http://www.qsl.net/ok1rr/soft.html";>http://www.qsl.net/ok1rr/soft.html</A>
Dave WX7G
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