[TowerTalk] Tuning raised radial verticals

Gary Johnson gwj at wb9jps.com
Sat Sep 2 13:29:31 EDT 2017


Dan’s simulations and observations are spot-on as usual. So...

1. For the complete system, observe dump power vs. freq rather than SWR.

2. Frequency shift between resonance of a free element vs. that of the minimum dump power is <50 kHz, which is similar to my own experience. Why the manuals say to tune the verticals 150 or 200 kHz low makes no sense to me. If you simply tune your elements nearer to the middle of your intended operating band, results would be better.

3. Single radials are not good for pattern, as previously explained. If you add a second 1/4-wave radial, feedpoint resistance at resonance will be lower and in fact closer to the point design of the commercial phasing network. AND, ground losses will be lower. I cannot see what adding 1/8-wave radials would accomplish, intuitively nor in simulation. Perhaps someone can enlighten me.

-Gary NA6O


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