Building a 10 element DK7ZB Yagi

As I had build antenna's in the past for other bands I had used CueDee antenna's as the 10 and 15 element version for my 144 MHz DX work.
Seen the EME results were good but not as I excpected I searched around for other idea's. Arno PE1RDP had good results with the design of Martin DK7ZB and therefore I wanted to try the design myself.
I had rebuild the old 10 CueDee to an 8 ZB and that worked nice as tested in the garden. On the roof it had too little gain for EME work.
So the local aluminium supplier was visited and for 70 euro I got the desired material.
The antenna element holders were purchased in Germany via Nuxcom and these can hold 6 and 8mm elements.
I chose for 8mm elements because a larger surface has more chance of receiving signals .... and qrm hi. The boom length was taken just a bit longer than 6 meters to be able to apply plugs at the end.
The dipole is matched with a 28 Ohm impedance transformer made of TV coax-6 ... the green stuff cable-TV guys use in Holland and has been taped to protect it against UV and weather attacks.
The dipole inside the plastic box has a center spacing of 10mm which is achieved by a teflon piece (see other page)
The boom is made of 20x20 mm AL and is supported with the same material 20x20 mm AL to avoid bouncing up and down in the autumn storms.
The antenna was put on the roof on april 25th 2009. The SWR was tuned to 1:1 exactly.


The 10 element DK7ZB performs as well as the former 15 element Cue Dee. The Cue Dee was 7.40m long while the DK7ZB is only 6.00m !!! Wow what a great long Yagi design.
Tuning was a little more difficult then the CueDee gamma match but an SWR of 1:1 could be achieved by cutting off thin slices of aluminium from each dipole end ....yes some work, but you see the SWR drop as each part is removed.


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