VERTICAL 30/40m

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   For 30 and 40m I opted for a vertical antenna with elevated radials, like that the system is relatively simple. I have used some of my own accesories, like this all was quickly installed. Some technical informations :

- Vertical part is composed by a 7m fishing pole

- Choke balun and impedance transformation are in the same box.

1. -An homemade coil is used for the 40m and 80m. But on 80m, antenna has a very bad efficient because of the small vertical part.
   

2. -Elevated radials : 2 of 10 meters long for 7mhz and 2 of about 7.5 meters long for 10mhz.
   

   The general assembly looks like that :

1. -Install a wood post of 2.5 meters long, with an electrical box and the fishing pole fixing.
   

2. -Put 2 horizontal radials of one quaterwave for each bands at 2.5 meters above the ground.  With an antenna analyser, I tuned each pairs of radials for the better resonance (X=0).
   

3. -The vertical wire is about 7.2 m fixed along the fishing pole.
   

4. -Install the 40/80m coil and the choke/transformer (set on 25 ohms).
   

5. -Step by step cut the vertical wire for the lower SWR on 30m. Then find the best points on the coil for 40 and 80m.
   

   At the start, I changed bands manually, but I finaly used some relays in order to remote that.

   You will find some informations about my choke/multi ratio balun at this link :

- WB6ZQZ : Alan Biocca and his triple ratio balun. All informations are on his website.

   In this configuration the antenna works well, but some things need to be improved :

- Replace the choke/multi ratio balun by a coaxial choke + a shunted matching coil for 40m.

- Replace the coil by an other coil just for 40m

- Supress the idea of 80m on this antenna

- Add one more pair of radials for each bands.

   For a quick and cheap installation this antenna perform very well especially on 30m where I often made QSO with japanese stations and others DX.