About this site

This site is a non-commercial, non-profit collection of online tools, developed solely by radio amateur Rob DM1CM, and offered free of charge for use by radio amateurs and others interested in radio technical matters.  The site features easy-to-use tools to help users design simple, lightweight, but effective wire antennas which are especially suitable for portable use while participating in any of the several amateur radio outdoor award schemes.  Read more about the development of the site...

Antenna types

Currently, the site offers tools to help the user design nine different types of portable wire antennas.
Detailed notes covering each antenna type are to be found in the antennas support page.

 

Contact form

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You only need to click the "Send" button once.  I'll try to reply within a day or two - if you do not receive a reply within this period, please check your email spam folder!
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Website development

Design, development and maintenance by:  Rob, DM1CM

This website does not use 3rd-party cookies, is not monetised, does not contain or use advertising, tracking, or analytics of any kind, and does not receive or store any user data.

I must admit I've always been very reluctant to call attention to my self, preferring to let my work - such as it is - speak for itself.  However, so many people have made enquiries as to who is behind the site, who has developed it, whether it's a commercial site (it isn't!), and so on, that I felt I ought to at least give my name and callsign, so that those interested can do research online to discover more about me.  A few details are given in my QRZ.com page and a few further references can be found in various forums.

I previously developed the sotamaps.org website for SOTA, and the mapping routines for the IOTA website.  The precursor to this present portable-antennas.com website was a single page in the sotamaps site, a Linked-Dipole Antenna designer, which calculated wire lengths and angles, but which had no access to a NEC engine, and so offered no radiation patterns, VSWR chart, etc.

Starting in 2022, I began to work on what would become this present site, by including a new version of the Linked-Dipole designer and adding a couple of new antenna types.  I also wanted to include radiation patterns and a VSWR chart, but wasn't quite sure how to do this.  After searching for software to enable such diagrams to be created and displayed, I did find some which enabled me to add them into this site, but the routines turned out to be slow and inefficient.  Eventually, in 2024, I "graduated" to using a NEC v4.2 engine, and developed my own back-end routines running on the server to extract relevant information from the NEC-generated data, and also developed my own versions of radiation patterns diagrams, VSWR chart, antenna currents diagram and Smith chart.

As is mentioned elsewhere, this site is a work-in-progress, with updates, corrections - and even new features - being added as time permits.  If you find an error in the site, or would like to suggest improvements to the site, please use the Contact form above to let me know.

One last point: I occasionally use the "royal we" when describing various features in this site, not to give myself more credit than I ought to do, but rather to acknowledge the immense debt of gratitude I owe to all those hard-working developers out there whose work I have so shamelessly copied and purloined.  We are all brothers in this endeavor.

Hope you enjoy the site!
73, de Rob DM1CM

 

Acknowledgments

I've recently updated the software used in this site to generate antenna radiation plots data, and also the plot routines themselves. By developing my own software to analyze the NEC-generated data, and my own chart-plotting routines, I have eliminated several third-party software "plugins". This has resulted in tighter, faster data flow to you, the user.

I am grateful for the opportunity to use these resources, and acknowledge a sincere debt of gratitude to their respective developers.

Please note:  due to the reliance on sizeable graphics and groups of controls in this site, it is not suited to display on small screens. I apologize for any inconvenience this may cause.

 

portable-antennas.com - Site health monitoring

The aim is to keep the uptime of the website server at a 99.9% level. In order to keep a close watch on this, I'm pleased to make use of the services of the live dashboard provided by UptimeRobot. This service is offered free of charge to non-profit hobby-oriented sites like portable-antennas.com. Click here to view uptime: UptimeRobot logo
 

Disclaimer

All information on this web site is provided "as is", for general information purposes only, to the amateur radio community and those with an interest in radio technical matters.

The operator of this web site makes no representations or warranties of any kind, express or implied, about the content, completeness, accuracy, reliability, legality, suitability or availability, with respect to the website or the information, products, services, or related graphics contained on the website, for any purpose.  Any reliance you place on such information is therefore strictly at your own risk.