[TowerTalk] Gamma match

[Michael Baker]

Hi Peter,

	If I understand all I think I do, what you are intending is not
possible.
	A gamma match is applicable only if the center impedance is LESS
than 50 ohms. With almost 61 ohms and nearly Ø reactance the worst case SWR
should be 1.2 to 1 fed in the center with a split element. 
	You could just use a hairpin match attached to the split driven
element and the center of the hairpin attached to ground and feed it with a
4:1 Balun at the 200 Ohm point. That would give you a grounded antenna for
static suppression issues. Just a thought. 
	OR use a T match (Two Gamma Rods, one on each side) and a 4 to one
balun and a grounded element. 
	

Michael Baker  K7DD
k7ddmjb at qwest.net

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Peter
Sent: Saturday, May 02, 2009 8:58 AM
To: towertalk at contesting.com
Subject: [TowerTalk] Gamma match

Hi

I like to make a rotory dipole for 40 meter (full size)
For constructions reasons I want to feed the the dipole with a gamma match.

Nec4win says that the impedance will around  60.8 +j0.12
How can I calculate the correct gamma rod length and the needed C?

TIA!

Peter
PC2A
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