A Vertical Antenna for SOTA (a project I am still working on)

The vertical has had a number of runs since the first post.
I have not actively compared its performance to my end fed antenna. But it seems to be no less efficient as I have worked a few JA station on 18MHz when using it.

The design remains similar with the exception of adding a 1:1 current balun. This was introduced to isolate the coax from the antenna system, as I noted some variation in VSWR as the coax was moved. This was discussed here on the SOTA reflector (look for post #7)

I have remained with the3.7m radials but I have increased the number to 8 (yet to be tested).
After reading An experimental look at ground systems for HF verticals (second link below) I may increase that number to 16.

Further Reading;


Naturally the internet is most people go to when it comes to research, to date I have turned up three items of interest

Some Rules of Thumb for Ground Radials

I have also found some interesting reading by Rudy N6LF, Rudy has done a huge amount of work with antennas. two articles caught my with regard to radials for vertical antennas;

First one, on this page look for Series of QEX articles on ground system experiments
The summary of these articles are covered in this document Download QST March 2010 Ground Systems

The second one looks at radial length for shorter verticals, one this page look for Are the lengths of radials related to the height of a vertical? to find the article Vertical height versus radial system

6 thoughts on “A Vertical Antenna for SOTA (a project I am still working on)

  1. Hi Warren
    I am looking forward to the next episode. I would like to try a vertical on 40m in the field. Not sure yet of the best way to proceed.
    John D

    • Hi John,
      The work on the vertical has paused again, this is mainly due to the need to run 80m on most activation’s. Running 80m adds extra time and the need to erect two antennas if I wish to run the vertical.
      I have not experimented with a 40m vertical, but based on the recent revisit of the end fed to run on 80m I would suggest the important points for a quarter wave vertical are;
      make it as tall as you can,
      shift the loading coil (if using one) as high as you can,
      and make the radial system with as many radials as you feel happy with.

      I notice that the QRP Guys are sell a couple of vertical “kits” either of these could be worth a try.

      Good luck,

  2. The key in my experience is to use full size verticals and get the base a few metres off the ground. You then only need 2-3 radials and as they droop down the feedpoint is closer to 50 Ohms. VK3IH

    • Hi Paul,
      Yes raising the feed point will improve the feed point impedance and the performance of the radials.
      However I am stuck with the squid pole I had (5.4m) which means the quarter wave length on 20m needs all of the pole, so feed point is on the ground.
      I also found the need to put antennas up and down to change bands (End Fed wire and Vertical) time consuming so tended to take the easy option and just use the wire. But the vertical has been in my mind again so might be time to re-visit it to improve its performance both from an RF and field deployment perspective.
      73, Warren.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s