Topband: VERTICAL ANTENNA MATCHING

[Richard (Rick) Karlquist]

Mr. and Mrs. Magoo wrote:
> There have been quite a number of posts recently requesting info on how to 
> match an inverted "L" or a short vertical.  Most of the responses suggest 
> one method or another, but I have seen very few suggesting using an inductor 
> at the base to ground, tapped down for resonance and up from ground for 50 
> ohms.  Same thing on ON4UN's book-I believe there is one reference to this 
> method of matching but many using L-networks and ununs.  What is the issue 
> here: efficiency?
> 
> I always thought that this method worked all right, particularly if the 
> antenna was longer than 1/8 wavelength and top loading made it possible to 
> use a very small inductor at the base.  The bonus seems to be that such a 
> configuration makes the antenna somewhat quieter on receive and may offer a 
> measure of protection from Thor.
> 
> Comments?
> 
> Bill, VE3CSK 

This is an OK method, but it is somewhat clumsy to tune, especially if
you don't have fractional turn resolution.  Also, it assumes the 
vertical is base loaded.  I have top loading wires on my vertical, so
the input impedance is not necessarily capacitive, and this method
doesn't apply.

Rick N6RK