The quickest way to increase the range of a ham radio is by using a more efficient antenna. A popular ham radio antenna, especially in non-permenant mounting situations, is a Slim Jim antenna. The Slim Jim we will use is a portable end fed folded half wave dipole and quarter wave J configuration for our 2m/70cm band radios.
We will not be making the antenna itself. If you are interested in buiding your own Slim Jim antenna, a Google search for “Slim Jim antenna” will provide all the information you need to make one. I don’t have the time or resources to do that right now so we are going to buy the antenna and focus our creative energy on the antenna mount. The roll-up Slim Jim can be hung from almost anything, but we want something with us for when there isn’t anything to hang the antenna from.
Since we are not making the antenna, we wanted to buy a good one at a reasonable price. We got the Slim Jim antenna from N9TAX Labs. The antenna we bought from them was well built and reasonably priced. N9TAX Labs has a good reputation for quality antennas, that’s true of the antenna we purchased.
To build a portable antenna mast, we used PVC tubing. PVC is easy to work, inexpensive and readily available. We want the mast to be tall as possible but sturdy in moderate wind. It will attach to my truck roof racks and assemble quickly by one person without tools.
The mast is made in three parts. There is a 1/2″ OD piece about 2′ long that slides into the roof rack crossbar. The lower piece is 3/4″ PVC for strength, attaches to the piece stuck into the roof rack crossbar with simple U-bolts. The top piece, that holds the antenna itself, is made from 1/2″ PVC. 3/4″ could be used as well, but it adds weight.
This is the complete antenna and mast. The antenna and hardware are in the plastic bag next to the disassembled mast sections.
This is a photo of the lower section of the antenna mast, the PVC sticking out of the roof rack crossbar and the U-bolts to secure them.
Looking up from the mast mount to the roof rack, the top part of the antenna mount that holds the antenna itself.
Below is the basic configuration of the antenna during wind testing in the Columbia River Gorge, one of the windiest places in America.
Using a cheap Baofeng 5w handheld transceiver and the Slim Jim antenna, it was able to reach repeaters over twenty miles away.
Now you have a portable antenna that will greatly increase your ham radio’s range without spending a lot of money. If you don’t use the antenna mast, the Slim Jim can be used by itself by hanging it from something.