What I like most in antennas is measuring. I saw three very distinct dips in the SWR when I connected my RigExpert to it. But they were not on the frequencies I wanted,........

Start with the lowest frequency, and try to get the dip on 28800 kHz (the band goes from 28MHz to 29.7 MHz). Don't forget to connect the radials !! And spread these nicely around the antenna. By changing the length of the lower part of the antenna (under the first trap seen from the connector,....change and measure, change and measure,.....until you get the SWR dip exactly on 28800.

If that is OK, start with tuning the 15 meter band. The length of the tubes from the connector to the highest trap should be changed until you see that the SWR dip is exactly 21225 kHz. Good,....after that the SWR dip at 28800 should be changed only very minimal. In my case it was only a few kHz.

Well after this change the length of the tubes above the highest trap, to tune the 20m band. Change it until you see the SWR dip on exactly 14175 kHz.

After this, check the three bands. Small changes here and there could be needed. But basically the antenna is now tuned. The lay out of the radials is not very critical, but it has an influence on the dips of the SWR (where and how deep).

So if you install the antenna somewhere (semi)permanent, play a bit with the radials in order to get a deep SWR.

In my case I put the radials a bit slanting, like a ground plane. It has a positive effect on the SWR. If you want you can get the SWR real 1:1. But it takes you some time to find the right layout.

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