[TowerTalk] Fwd: Adjusting a Gamma Match on a Yagi with an AntennaAnalyzer

[Bob Alexander]

On 11/9/2010 9:38 PM, n8de at thepoint.net wrote:
> The gamma match itself is an inductor ... you can only cancel that
> inductance by putting a series capacitor inline with it.  IF you do
> not, changing the length of the driven element will change the
> APPARENT impedance, but it will still have an inductive (reactive)
> component.
>
> 73
> Don
> N8DE
>
I have a couple of homebrew 4 el on 3/4 wavelength boom yagis  with 
gamma matches.  The antennas were designed to have a -j component at the 
feedpoint.  Using a gamma match without a capacitor resulted in a 
slightly inductive feedpoint impedance.  After shortening each end of 
the DE a  25 dB return loss was measured at the design frequency.   No 
inductive component.
73, Bob, W5AH