Simple ultralight SOTA dipole for 20m

Lightweight dipole for 20mLightweight dipole for 20m

One of the things that fascinate me in ham radio is the ability to build actually working stuff from very basic materials. I am still fascinated by the fact that you can communicate - e.g. using PSK31 mode - thousands of km all over Europe with more or less only double the power of a cellphone using a self built antenna made from basically 10 metres of standard wire. The very first version of the antenna described here didn't even have the balun and still worked.

This is a brief description of my newly built very basic and lightweight SOTA dipole for 20 m.

• The design is based on calculations performed by the SOTA linked dipole calculator which can be accessed here. I added a few cm of the calculated length in order to have some reserve for adjustments.

• When I did tune the antenna by changing it's length I did it for the most common setup I expect for SOTA activation, the inverted V form.

• During adjustment (cutting the length) SWR was 1:1.0 for 14.070 MHZ (my main use case will be PSK since I operate QRP and I can't morse ;-). I am aware that SWR is highly dependent from environmental conditions, I do not use HF amplifiers, so I do not care too much about SWR below 1:1.5.

• Main goal was minimal weight, I do not use fancy clips or insulation pieces, the wire is attached directly to the mounting plate and the self built balun is attached also directly to the mounting plate. The plate is a simple piece of plastic.
• The balun is a 1:1 current balun based on a design provided by DL4ZAO (Link to pdf, see page 33).