sota-antennas - Welcome

sota antennas

Welcome to sota-antennas.com! This site aims to provide the radio amateur with easy-to use tools enabling design and modelling of simple wire antennas suitable for portable use in the HF bands, and their performance checked, in a matter of minutes.

Of course, other antenna modelling and design tools and programs do exist - for instance: EZNEC Pro, 4Nec2, MMANA-GAL ^* and others - they are very powerful, and generally give very good results. The downside is that such programs are often very complex, and involve a steep learning curve in order to become proficient in even the simplest of tasks. Not everyone has the desire to spend so much time in gaining the skills and knowledge required.

A quick word...
If you have come to this website expecting to purchase that perfect cheap and lightweight 7-band portable antenna you've been looking for ... then this is not the website for you. Do yourself a favour and find an online antenna warehouse which will do same-day deliveries. Good luck!

Easy to use

The tools provided in this site take much of the complexity out from the task of modelling and designing of simple wire antennas. Parameters such as frequency, wire lengths and angles are easily input, and results presented in graphical form at the click of a button.

Users are encouraged to experiment with a particular antenna designer, to try different values of frequency, antenna section lengths, height of antenna above the ground, try out different ground types, and so on. Spend some time to see what effects these changes have on the antenna's radiation patterns, or on the VSWR, as the changes are made. In this way, you will learn a great deal more about your choice of antenna in particular, and also about antennas in general, than just trying one set of values.

Different antenna types

Currently, the following antenna types for the HF bands can be modelled, with more being considered for inclusion:

Linked dipole antennas - for single or multiple HF bands;
Off-center-fed dipole (OCFD) antennas - capable of giving good results (low VSWR) on several bands above the principal band;
End-fed half-wave (EFHW) antennas - capable of giving good results (low VSWR) on several bands above the principal band;
Vertical antennas - for one single band, with all-round, low-angle radiation - currently in BETA version ;
Delta loop antennas - for one single band, providing vertically-polarized emissions at low elevation angles - a good DX antenna.
Half-square antennas - can be configured either as a full-wave single-bander, or as an EFHW multi-bander.
Moxon antennas - for one single-band, a compact two-element beam antenna with good gain and very good F/B ratio.

In addition to the designers, the site also offers the

Extras page - data-sets and charts for various coaxial cable types, reference correction factors, and calculators

Radiation patterns, VSWR charts, antenna currents diagrams and Smith charts

For each of the antenna types currently supported, any combinations of the following charts and diagrams can be generated and displayed:

azimuth and elevation radiation patterns;
3D radiation patterns;
VSWR curves, incorporating real and imaginary impedance curves - VSWR curves are displayed for
either one single band, or over several bands;
antenna currents diagrams, showing how currents are distributed in the antenna;
Smith charts, showing how antenna reactance changes with frequency.

Export results

Results from the design and modelling can be exported in either PDF, CSV or simple text formats. In addition, antenna dimensions suitable for importing into a professional program can also be exported.

Background

Why "sota-antennas"? - well, this site takes over from the antenna designer in the soon-to-be defunct sotamaps.org site, and expands on it somewhat. The antennas covered here are primarily for amateur portable use, e.g. for SOTA activations, as well as for activations in other amateur award schemes like GMA and WWFF.

Now, we'll be the first to admit that the "sota-antennas" name, while conveying the right kind of idea, is nonetheless pretty lame. Perhaps you can come up with a better (family-friendly) name? - if so, we'd love to hear from you!

Please be aware that this site is a work in progress. From time to time, some functions may not appear to work, or may not work correctly. This simply means that those functions are in the process of being updated or changed. If it doesn't work now, check back later!
If any problems with the site should appear, or if they persist, let us know!

^* Use the above links with discretion - we accept no liability for the content of external links