Tag Archives: radials

Software Modelling your Vertical antenna ground radials with MMANA

I’ve been scratching my head for years how to model an appropriate ground with my ground mounted Vertical Antenna radials.

I’d like to thank Sigi, DG9BFC for clearing this up for me.

HOW TO:

NOTE: I like to draw a small feedpoint in all my HF antenna models, like a 5cm length of wire where my “source” (coax) is connected to. Particularly useful for fan dipoles and for making other adjustments. I’ve left that part out for simplicity on this How To since I’m trying to make this super easy.

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Salt spray detunes wires on fibreglass antenna poles

I use a lot of fibreglass poles with wires strewn up the sides, normally in a lazy helical fashion so that they don’t flap about too much.

I have great success with these poles as regular readers know however I have noticed that certainly wet weather can detune them ever so slightly. Effectively, they become slightly longer and I fathom that as the fibreglass supports become wet, I am achieving some slight inductance with the water that drips from the surface and gets between the wires and the poles. As soon as they are dry again, the tuning comes back to normal.  Continue reading