I tried to make some AO51 QSO's just with a vertical antenna and this worked quite well but the downlink signal was very weak. Then I found the info about Yagi antennas on the website of Martin DK7ZB (Click here) I never build a Yagy before but follow the instructions and it works! I first tried to build a lightweight 70 cm version with 6 elements. It worked the first time right with a very good SWR. Here some impressions: (click photo's to load bigger version)
As described by DK7ZB I made the boom from PVC pipe and used small welding rods as elements. The elements are mounted with cable clamps to the boom. I made some sattelite QSO with the vertical on the uplink and the DK7ZB on the downink. With the Yagi indoors (!) signal improved A LOT.I could see a S5 on the downlink. Happy with this result I decided to make a 6 elements 2 meter version for the Jota to replace the 4 element Tonna we normally used. I decided to use an aluminum tube for the boom. Here are some building pictures.
Here are the 2 yagi antennae on the outdoor table for testing
Im am not happy with the element mount using the 2 clamps. It is not stable and strong enough but it survived 2 JOTA weekends. Together with Vincent PD02VK we will work out another solution. Here some pictures of the 2 m Yagi during the Jota Weekend
mounting the elemens............QRP holding antenna...............in the mast
Al together I am very pleased with the antenna's and will thank DK7ZB for his nice work on designing and describing these antennas. This was the first time I build Yagi antenna's and together with another HAM (vincent PD0VK) and some scouts we plan a bigger one to use in the next JOTA I also noticed a new 2/70 dual band version on the website . Maybe I am going to build this for AO51.