THE “CARPOLE ANTENNA” – A CARDBOARD DIPOLE

Articles by Glyn GW0JAI and Martin GW0TWL

About 20 years ago, after reading an article in a magazine, I had an urge to build a coiled dipole but did nothing about it.

Recently Martin moved into a first-floor flat with no means of erecting H.F. Antennas and this resurrected the idea in my mind. In my shed I unearthed a 12' length of 4” diameter cardboard tube and another piece of about 4'.

(This was a good omen as my shack is 16' long).

I joined the two pieces together and wound an 80m dipole (with slightly more wire than normal) onto the tube, fitted it into the apex of the roof of the shack, plugged the feeder into the SWR meter, and had a reading of about 2:1. I then connected it via the ATU and this brought the SWR down to 1.1:1. Now I tried it on air and worked into Poole in Dorset, Cornwall, southern Ireland and Harrogate with reasonable reports.

At this stage, I raved on about it to Martin, and suggested that it might solve his problem as he has an attic above his flat.

After acquiring some more cardboard tube, Martin and myself each built a “Mark 2” version. The results from my QTH were greatly improved and I was able to work as for as Stornaway on Top Band (under good conditions) and France, Holland and Belgium on 40m. It was interesting to be able to compare results with Martin – this helped us both on developing the idea.

It is a simple and cheap antenna to build and open to any other configuration – I have tried it connected as a curly long wire and as a loop, and in both it works well. If you are interested in building one for yourself get in touch with Martin or myself for more information.

Glyn GW0JAI