ConstructionTo construct the antenna, the first thing you need is a cooper or aluminum rod 1 meter long. Cut it at 98.5 cm and round it until you get a 3 - 4cm gap. Your antenna is done. Now you need to connect it to the coaxial cable and make the appropriate matching network, in this case a Gamma match. Connect the braid of the coaxial cable to the center of the rounded dipole and solder a 22, 33 or 47 pF trimmer to the center conductor. Now connect the other side of the trimmer to the center of the dipole arm with a small cooper wire or similar.
Now you have finished the electrical antenna, but you need to make some mounting hardware to make the antenna usable. I made a PVC skeleton to support the antenna and, at the same time, to mount it over a magnetic mobile mounting. You can do in this way or in any other useful way to you.
I glued together some pieces of PVC to make the skeleton. I also glued a PL-239 socket at the skeleton bottom end. See the images for details.
Here you can see how the PL-239 plug is glued into the PVC:
And here the trimmer detail, over a small PCB board:
And finally, the antenna in its final form:
Once you have finished the mounting hardware, you need to tune the antenna. Simply put a low power carrier on 144.300 MHz and tune it with the trimmer. You would get easily the SWR 1:1. Bandwidth of the antenna is somewhat narrow. About 600 kHz. Not a problem for the typical SSB/CW work.