Building a Multi-band Fan/Parallel Dipole Antenna

Now that Solar Cycle 25 is upon us, I wanted to get active on the HF bands. My primary bands of interest are 40 and 20 meters, so I wanted to build a multi-band antenna for these frequencies. After some research, and wanting only one antenna connection for my Kenwood TS-2000 radio, I settled on a fan/parallel dipole antenna. It's very simple to build, and really hard to beat the performance of resonant dipoles.

Choke Balun

A balun is required when you are interfacing a BALanced device, such as a dipole antenna, to an UNbalanced device, such as a coaxial cable. Coaxial cables are unbalanced because from an RF perspective, there are actually 3 conductors in a coax cable: the center conductor, the inside of the shield, and the outside of the shield. The outside of the shield acts like another ground wire, and can bring RF energy and noise down into the shack.

This antenna and balun/choke design came from the 2008 ARRL Handbook for Radio Amateurs. I always encourage amateur radio operators to have ...

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Building a Quarter-Wave Ground Plane Antenna

After my talk at Pacificon a few months ago, several people reached out to me about setting up a radiosonde receiving station at their house. They specifically had questions about the antenna and LNA, and after answering the same question a few times I decided to do a post about this topic.

Building a 1/4 wave ground plane antenna is very easy to do. The overall design is simple, with a vertical element surrounded by a ground plane consisting of two or four wires bent down. Here are the dimensions for the VHF/UHF amateur radio bands (from the ARRL Handbook), but these dimensions can be scaled to any frequency.

There are many online calculators that will give you the approximate dimensions for the elements, but I usually use M0KUD's calculator. Whenever you are making antennas, always cut your elements a bit longer (maybe 20%) than the calculation says, then trim them during tuning.

Use any type of wire for the elements. I use standard 14-gauge solid copper wire because it's easy to get from the hardware store, it's ...

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