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

[Bob Alexander]

>> 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.
> And what happened to the resonant frequency and f/b and gain?  Any
> change to the DE length will affect all three of those!
> 73
> Don
> N8DE
>
>
>
The gamma match inductance has the same effect as adding a loading coil 
to the element thus making it electrically longer.   Reducing the 
physical length of the element moves the electrical length back to  the 
design frequency.
It is the electrical length not the physical length that matters.   
There is no change in antenna performance.
73, Bob, W5AH