Building A Portable Slim Jim 2 Meter Antenna

As you may have read, I’ve been working on a Baofeng-based foxhunt transmitter, and this antenna was built for this project. However, it should also serve well for any other 2 meter needs I have.

For the foxhunt transmitter, I wanted a simple, portable antenna that did not require a ground plane or counterpoise. I had tested a few rubber duckies, but the plastic box that houses transmitter and controller did not provide proper counterpoise and the SWR tested unusably high. So, instead, I looked at the slim jim and j-pole antennas constructed from 300 ohm twinlead. Either of these would provide a simple to deploy and portable solution.

I had tried previously to construct a twinlead j-pole with decent but not great results, so I still had some of the twinlead left in my parts box. The slimjim offers the advantage of having a slightly shorter overall height which i thought might help with hiding it for foxhunts. Construction was fairly simple, following the instructions on Hamuniverse. My largest problem was in connecting the SMA connector on my RG174 cable. I found that stripping the cable properly for the connector as well as actually soldering the center pin sufficiently was a bit of a challenge. On the third try, I managed a good solder, no shorts, and a workable crimp. Tests on the NanoVNA while suspended in the edge of the room away from metal obects show a 1.2:1-1.3:1 SWR across the whole 2M band which should work great for this purpose.

I added additional waterproof heatshrink everywhere wires were exposed in hopes of keeping out moisture when deployed outdoors. Finally, I poked a hole in the top piece of heatshrink and added a thin 1mm waxed polyester thread to make a loop with which to hang the antenna. I also added a snap-on ferrite choke, which some sources suggested would help the antenna.