Today, I used a piece of United Kingdom household electrical wire to make an antenna. Not sure what other countries use but here in the UK it is, one blue and one brown with a bare earth wire protected with an outer grey covering. Certainly stiff enough for my purpose.

Household electrical cable

I cut a 70 cm length of wire which I soldered to the BNC connector. For those in the know this would be too long but remember it is just a piece of wire hooked up to the antennae measuring device (RigExpert AA-230 ZOOM) and no earthing as such… on we go!

Keep on trimming pieces off .. slowly you will see the effect the length of the conductor has. Cut a piece off the prospective resonance frequency on the antenna will go up. We need the SWR dip at about 127 MHz.

Here are the readings for the 60 cm and 59 cm wire antenna SWR graph readings respectively…. on our way to middle of the band. Snip, snip …

60 cm wire length
59 cm wire length

After quite a bit of trimming, and an over trim (replaced wire) I was able to get the mid air band frequency of 127 MHz.

The successful reading of 127 MHz

All tuned, but with a SWR of 3 hardly usable.

*GOLDEN NUGGET * The most interesting thing so far is that changing the distance the antenna (without a ground plane) is above the ground, the SWR reading is variable and I was able to adjust to the best SWR reading I could get.

This is the biggest give-away that an antenna needs a stable ground-plane and not just anything will do!

My next adventure is to start fitting a ground-plane. Here again I will start with wires of 70 cm for the ground plane and trim them down to get the best SWR.


No responses yet

Leave a Reply