As I like building new antennas and always want to experiment with them, I also wanted to try the new dualband Yagi design for 6m and 4m by Justin G0KSC.

These antenna designs are especially good for noisy environments like mine, and the feedback af many radio amateurs was positive.
I had a look at all the designs and the closest replacement for my current 4 element singleband DK7ZB was the 4/5 element dualband LFA Yagi.
The gain was about the same on 6m (50MHz) but the F/B ratio of the LFA was much better.
After making a list of material to use, I went to our local shop and placed an order for all the aluminum I needed.
I got the european measurement dimensions from Frank IZ8DWF as we only have 12mm aluminum in stead of 13mm as described by Justin.



The coaxial cable I am using is Aircell-7 for light power use, up to 100 Watt as I can only run legal power of 50 Watts.
I used a bigger diameter boom of 25x25 mm aluminum as the elements on 6m are rather long and I'm only using small element holders which must put all mechaninical stress to the boom.

Here is a picture of the dipole connection with the coaxial balun :



All the connection materials are made of stainless steel to prevent rust getting grip on the antenna.
Today (12-5-2012) all mechanical work has been done and the antenna was put on the roof. No testing in the garden, it had to work, no worries.

I did not tune the dipole (6m radiating element) and VSWR was already 1:1.3 on both bands !!!
See the read-out on the Diamond swr-power meter:



I also made a frequency sweep with my Hameg spectrum analyser and you can clearly see the matching dips on 50Mhz and 70Mhz (marker set on 70.1 MHz):





16-5-2012 by PA3FXO


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