2 Meter Yagi Antenna with Gamma Match
How to build a 2 meter yagi antenna with a gamma match. Simple and easy to make using parts from an old TV antenna. You'll love this small high gain 4 element yagi beam antenna.
If you don't have an old TV antenna then you'll need some 3/8" aluminum tubing for the elements and the gamma match and a 1" square aluminum tube for the boom. Add some small aluminum strap for the gamma match, a piece of angle aluminum for the feed-point connector and an SO-239 connector and you've practically got it made.
Making the Gamma Match
This video demonstrates how easy it is to make a gamma match for a 2 meter yagi antenna. You may use this gamma match on a much larger 2 meter yagi, too. Some hams prefer to design their own yagi antennas and might find this style of gamma match very useful.
The gamma match is made using a 3/8" aluminum tube and a piece of RG-8 coaxial cable. The outer jacket and the shield is removed from the section of coaxial cable. The center and dielectric of the piece of RG-8 is then placed inside the aluminim tube. This forms the capacitor for the gamma match. All details are included in the video.
For element spacing I simply removed the original blue insulators from the boom and reused the same holes. The spacing is 12-3/8" between all antenna elements.
Video Instructions Watch this two part video below to learn how to make this antenna.
Tuning is done by sliding the gamma match tube back and forth. The grounding strap on this antenna is postioned near the end of the tube and the tuning is a bit tight.
My coaxial cable length mentioned in the video is incorrect. Instead of the way that I calculate the length of coaxial cable to use you should instead use multiples of 1/2 wave lengths. It is not critical to do this but doing so should reflect a more accurate SWR measurement.
Remember though that after testing and tuning your antenna just a few feet above the ground the SWR reading may change a bit after raising your antenna to a much greater height.
Well after watching the youtube video,and writing down the dimensions, I headed to the barn and the magic started. I had recently obtained an old TV antenna from a neighbor who removed it to have a new roof. Anyway, 2 hours later, I am bringing up repeaters 60 miles away with my HT and 2 watts!!!
It's a great antenna, and I built it for possible ecomm deployments.
Thanks for a great project. Your videos are the best.
73 de Chris