[K6ARK] likes to work portable, so he puts together very light antennas. One of his latest uses tiny toroids and SMD capacitors to form trap elements. You can see the structure in the video below.
Usually you think of toroidal windings as something you do when building transmitters or receivers, especially small ones like this one. We assume that the antenna is best suited for QRP (low power) operation, as the tiny core would saturate fairly quickly at higher power. How much current you should pass through an FT50-43 core depends on the exact application, but we have numbers seen around 5 watts.
The SMD capacitors are mounted directly in a chopped BNC connector. This leads to a very compact construction at the expense of a little fine work with a soldering iron when building. For more construction details on similar traps, see a second video that you can watch below.
The availability of antenna analysis devices makes such projects easier. The concept of the end-fed half-wave has its critics and supporters. [AA5TB] has a Page that explains a little about antenna theories. Regardless, [K6ARK] says he’s worked on this type of antenna around the world and many people swear by it.