Beam

This project was in my mind during a long time. For space reason I chose to build two 6 elements Yagi for 10m. There is many advantages to use a wire beam :

Cheap antenna

Quickly install a good antenna system

Possibility to create very long boom and high numbers of elements

Allow good performances during a portable or temporary operation

Test an antenna design

It was also an other comparison to my permanently antenna : the hexbeam. For that, I decided to install two antennas : The first to USA and another to Europe. It was during the CQWW SSB 2012 contest.

I started to optimize a 5 elements yagi by DK7ZB, then I studied a solution for a wire beam installation : 110° angle and 7m from ground level. The 110° angle between the left ant right side of the antenna offers less performances than a true horizontal Yagi, that’s why I added another element.

Finally the design gave me these dimensions :

Reflector : 5.07 m

Radiator : 4.93 m

Director 1 : 4.68 m

Director 2 : 4.59 m

Director 3 : 4.48 m

Director 4 : 4.38 m

Space Ref - Rad : 1.43 m

Space Ref - Dir 1 : 2.16 m

Space Ref - Dir 2 : 4.80 m

Space Ref - Dir 3 : 7.50 m

Space Ref - Dir 4 : 9.31 m

Angle between right and left : 110°

Build this antenna is simple. I used a cord between to wood post of 8.5 meters, then a little piece of plexiglass allows to attach support cord and one element. The wire is bare copper 1.5 mm2 and coax RG58.

The antenna have an impedance of about 25 ohms, I used different shunted matching coil for make the coax adaptation. It worked great !

After 3 days of test, more than 400 qso, the 2 wire beams have been uninstalled. I can say it’s works fine ! For portable operation it could be a great solution.

Of course, there is nothing to compare between them, the first have 6 elements and the other have only 2 elements. But in this case the hexbeam is used like a reference antenna.

I took few videos and like you can hear, the difference is huge. The 6 elements improves the signal and reduces QRM, and don’t forget for the wire beam : one is at 50° and the other at 310° so it’s not the optimal beaming for T30 or KH6. I tried many directions on the hexbeam but the wire beams have always won.