Improve your signal with this compact "Stu Henderson 2 m Yagi Antenna"
I constructed this antenna more than 15 years ago and found this antenna to be the best small Yagi I ever constructed for the two meter band. I have worked many a competition with this small but very effective Yagi. Yes, I know there are many other designs out there but show me a five element Yagi that would out perform this Stu Henderson Yagi and I will build it. I build this antenna using the plumbers delight method with no isolation stand offs. I used the gamma matching, similar to the Dip-Yag Antenna matching. Although the gamma does effect the E-plain pattern it is not significant to influence the effectiveness of the antenna. The construction of this antenna is easy and works exceptionally well as can be attested by Nico ZS4N who also build and used this antenna. Unfortunately myself as well as Nico do not have any photos of this antenna to publish here but the complete PDF file is available HERE. (73 Amateur Radio Today - September 1992)
Just a word about the gamma match. You are more than welcome to use the gamma described in the article. I however use the same gamma that I used in the Dip-Yag antenna available HERE.
The gamma match consists of a 150mm length of 10mm aluminum tubing. The 200mm piece of RG213 co-axial center (the outer cover and braid is removed) is slipped inside this tubing which telescopes into the aluminum tubing. One end is then soldered to the connector. Sliding the RG213 center in and out of the tubing tunes the gamma match. Take the 60mm aluminum tube and drill two 10mm holes 25mm appart through this piece of tube. Fit the 2 x self-tapping screws on the side of this tube. These screws act as a “lock-nut” to tighten the element and the gamma match for the best SWR. Affix the boom with a mounting bracket to the mast. Note: The best SWR is obtained by moving this matching stub up and down, as well as the sliding of the RG213 center core in and out of the 150mm piece of tubing. After obtaining a 1: 1 SWR tighten all screws and affix the co-ax cable to the boom and mast with cable ties. One 10mm- and 20mm plastic end cap is affixed to the other end of the boom and to the end of the gamma match. Seal all holes and openings with an appropriate water tight sealer.
Finally: This antenna is a real winner. If you are looking for a great, portable and conpact Yagi antenna then this Stu Henderson Yagi is for you. It can be mounted either horizontally or vertically. The gain measured in a Lab on a 20:1 model using a standard gain horn was 13.8 to 14.1 dBi over a 3% bandwidth. I obtained a SWR of 1.2:1 at 145.500 Mhz however this can be altered by adjusting the gamma match. Even though the antenna described here is for 2 meters the same parameters work just as well for any frequency. See the PDF file for more information in this regard. If you do build this antenna please send me photos of your build. I will gladly post them on the GRHub Network Blog.
