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Best matching type

The20poundhammer

Sr. Member
May 23, 2016
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McKee Ky
Question for you antenna experts here. What is the best matching system for a beam. Is it a balun, gamma match, hair pin or something else. Going to be putting up a new beam soon. Putting around 3 to 5 kw rms into it. Thanks for any info.
 

The DB

Sr. Member
Aug 14, 2011
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St. Louis, MO
Depends on the beam. Some are designed to tune straight to a 50 ohm load, at which point using a choke or a 1:1 balun would be all that you need, and maybe not even that depending on the situation. Otherwise, should you need a matching circuit, you are not going to notice any difference between most of your options, so go with which ever is most convenient.


The DB
 

Captain Kilowatt

Professional Amateur
Staff member
Apr 6, 2005
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Nova Scotia,Canada
Depends on the driving impedance of the antenna. When I built my six element 6m yagi the impedance was quite low, somewhere around 12 ohms. I used a Beta match aka hairpin match and a 4:1 half wave coaxial balun to match the approximate 12 ohms to a nominal 50 ohms. Worked like a charm plus the Beta match is less lossy than a Gamma match and the entire antenna including driver element is at ground potential.
 
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BJ radionut

Supporting Member and 6m addict
May 9, 2008
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The Gamma match IMHO is the least preferred...tends to distort the beam pattern, easily effected by weather (over time)(it's a floating capacitor)hanging on a bracket above or below the driven element.
I prefer direct feed or as CK... Hairpin type match...The beams impedance is the factor.
All that depends on what your building the beam to do.
Max forward Gain or Max rejection … overall bandwidth … width of the beam pattern...Noise factor etc.
You can't have them all together, thus the design is based on those factors.
Some are direct 50 ohm feeds, others require a matching network.
All the Best
Gary
 

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