Topband: Re: 160 Loaded Vertical Antennas (Barry, W9UCW)

[Dan Fitch]

To: Dennis O'Connor, Michael Tope, et al,

Mike’s message:
The other interesting thing to consider is why a center loaded
antenna exhibits a current taper across the inductor whereas the
inductor in a base loaded antenna would not

Mine:
The moderator bounced my earlier message - - probably too wordy.

The short answer is cosine distribution of current on the antenna.  It isn’t
linear across the length.

Consider a Smith Chart, and place the loading coil at various positions
there.  A loading coil that shortens the antenna by 20° may see a 6% current
delta [ImaxCOS(q)] when located at the base, 23% when at the 30-50°
location, and 33% when at the 60-80° position.

73’ de Dan/KB4L