Monday, December 12, 2011

DF8QK 1296Mhz Transverter

Years ago I got hold of some partially completed DF8QK circuit boards. At first I built the 1296Mhz receive converter and after a lot of messing I finally heard a signal for the first time on the 23cm Amateur Band. Next I completed the three stage pre-amp and although quite noisy, managed to get it working as well.

This project took me ages to build and eventually I partially completed the transmit mixer. I assembled the units using copper clad board to make boxes for each unit with bnc sockets and plugs to connect between each unit. It was a bit of a nightmare to have, with wires everywhere!

The transmit mixer worked fine, but each time I wanted to use it I had to tweek some of the trimmers to make it work properly. I was truely amazed when I managed to work a station in France during excellent tropo conditions with just a few milliwatts of power!

Having worked a few stations on 23cm, my next project was to try to put all these units into a case and also build the power amplifier to give it some more power output.

For a while the transverter worked, but with a few problems with alignment that had to be constantly tweeked again. The big problem with the 23cm band is that nobody uses it unless there is a contest or tropo opening, so I never really new how well the transverter performed.

I still have the transverter, but it has not been powered up for years as I 'lost' the circuits and alignment details.

Last week I came across an old floder in my attic and guess what was in it? The circuits for the DF8QK! I was my task is to try to get this beast working again after so long. I don't know if it will be successful, but you can but try!

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