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

[n8de at thepoint.net]

Quoting Bob Alexander <realex at flash.net>:

> 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.

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


> 73, Bob, W5AH
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