Archive for the ‘ Antennas ’ Category

2x13el 70cm DK7ZB Yagis

For some time ago, I built two 70cm yagis to be used in the NAC contests. These are 2 antennas with 13el each and a DK7ZB design. Each antenna has around ~14dBd gain and the two of them stacked should have ~15-16dBd gain including cable losses. This day had crazy winds and sometimes I really thought that the tower would break or at least that I would. But after some struggling and twisted ropes I got them up and mounted.

New tower section

It has been a long time since I last updated this blog but now I’ve had some time over to write new posts. My tower has now one more section and finally I can see over the trees! This makes a huge difference in contesting on high bands like VHF, UHF etc. The weather was good and no wind so it was pretty easy to go up with the skylift and attach the new section. Took about half a day.

Clearing tower for new section

Today I’ve done some work around the tower. I am going to put up a new section so all the cables had to be cleared from the tower. Really unwieldy cables to wind up! Maybe I’ll take down all the antennas and other stuff in the tower tomorrow. I also have to fix better guy lines as I am now using real guy lines on the first section but only blue rope at the second..

6×2 Antenna Switch – Control Unit

Today I had little time to finish the antenna switch, but I had enough time to drill and mount all the LEDs and switches on the control unit. I bought 12 position switches and put the limit to 7 positions, 6 for the antennas and the last one for remote operation.

Also I soldered the rest of the cables between the relay board and the interlock board. Now the antenna switch box is ready, only the control unit left.

6×2 Antenna Switch

I finally got my hands on all the components needed for my 6×2 antenna switch system. The PCBs are made by SM2WMV ( and are of high quality! The making of the alu. box took more time than I thought just because I was out of screw-nuts for the SO239 antenna connectors so I had to snitch 2 or 3 from other stuff of little importance, the results of the snitching was not so good though..

I did not have time to solder the cables and the remote control box is also at the “to-do list”. My idea was to make 7 options for each radio, switch 6 antennas and the last one is for turning the antenna box remote capable without desoldering all the cables.

The drilling went easy and was done quickly!

Heh.. As I said, the results was not that good.. But I made it!

The complete connector plate

PCB mounted and ready for soldering

The brain in the switching system. Also a design by SM2WMV. Interlock Card that makes it impossible for the 2 radios to use the same antenna.

I hope I got time for the soldering part tomorrow…