Topband: Linear loaded whip versus base /center loading verticals / shorted Inv L

[Tom Rauch]

> 2) Inverted L with loading coil at the top of the 30-foot vertical
> section.
> 
> 3) Linear-loaded 30-foot vertical.
> 
> 4) 30-foot whip center-loaded with coil.

Actually a linear loaded antenna (assuming a helical wire the whole 
length) has about the same radiation resistance as somewhere between 
base and center loading. It ranks in somewhere that area for 
radiation resistance.

The main problem with helical wound antennas is they have very very 
poor form factors in the "loading inductor" and so are VERY lossy 
compared to a good lumped coil system (even when base loaded).

You can see this effect in mobile antenna shootouts, where linear 
wound mobile antennas consistently rank at the bottom of 
pile...almost always far below base loaded antennas.

With that in mind, I'd rate a linear loaded (helical loading) antenna 
dead last.

73, Tom W8JI
W8JI@contesting.com