Saturday, November 12, 2011

2m/70cm dual band yagi tests

During the last couple of weeks I have had a chance to evaluate the new 144/432Mhz dual band yagi through the Tuesday Evening contests.
First 2m...the yagi has 5 elements and is tuned well with a vswr of almost 1:1. During the contest I was amazed at the stations that I heard and worked with my Yaesu FT817 with just 5w output power. The rotator is working fine and I was able to test the direction and also side lobes of the antenna. It seems quite sharp, about what I would expect for a 5 element yagi, my old antenna was an 8 element J Beam and was slightly sharper. The main thing was that everything I heard that night on 2m, I worked with just 5w! Conditions were flat, but I worked Hampshire, Buckinghamshire, London, Bristol and the East Coast.

This week on 70cm again the yagi seemed to perform well. This yagi has 8 elements on 432Mhz. I found this a little tricky to get the beam settings right at times, it does seem to have some side lobes and with 8 elements it is not very sharp. My old antenna was an 18 element parabeam, this was obviously much sharper with a higher gain factor. Again, I was quite amazed at how I could hear and also work the stations on 432Mhz with just 5w. G8OHM, M0GHZ, G3PYE/P just some of the stations worked from all over England.

I am really pleased with this antenna, it was easy to put together and set up and does not take up too much room. The configuration of the elements look quite strange, usually a normal yagi has the longest as the reflector and each element gets progressively shorter. With the dual band yagi, this is not the case, all to do with the tuning I guess. The yagi is a bit of a compromise really, but it puts me back on the map again as a station especially when conditions open up to the continent on 2m and 70cm. I also realised how my location makes a difference, I am on the top of a hill about 114 metres asl with a good take off to the South.

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