50MHz 4-element Long Yagi
This antenna was designed in my ARC, OZ6FRS in 1998, as a club-build project. It has turned out to be a very well performing antenna with a few mechanical problems.
It's built with a round 32mmŲ boom and 20mmŲ elements, originally it was designed with it's own boom-to-mast attachment, but this turned out to be too weak, and I used one from an old Parabeam.
Some users reported trouble with antenna resonance, and after some experimentation, the solution illustrated below worked consistently.
Drawings below are scaled down to very small, just to indicate what they are, if you right-click on any of them you can then "save picture" it in full resolution
All drawings can be fetched in high resolution by right clicking and "Save Picture"
Here it's seen that the feeder has been removed (by about 5cm) from the boom, using plexiglass
spreaders. The balun is simply one turn of the feeder through a 4C65 Ferrite ring.
I had some SWR problems in rainy and snowy weather, which I solved using a sheet of PFTE
It doesn't get much better than this! Return Loss in excess of 50dB at resonance.