To be QRV on different HAM bands the "BATC" has
started a project. Through the club you can buy some circuit boards you have
to fill with parts you need to buy yourself. You also need a raspberry Pi 3,
a touch screen, and ofcourse all the parts to get to satisfying end of the
Picture on the left what you need and can/could be bought through the
When you installed the software, installed the touchscreen you already can use the Pi to make a DATV signal in UGLY mode. This mode is to "ugly" to put on air and can only be used as a test signal across the shack. The signal transmits on 437Mhz, but can be adjusted in the software.
The RF output switch and 4 band decoder are put together. But in the meantime I already ordered the 8 band versions. This gives the opportunity to switch between 8 bands, so you can use transverters for higher frequencies. Here in PA country the 70/145Mhz can`t be used due to band limitations.
To receive in ugly mode I also bought the Minitiouner V2.0 board+tuner.
So I can test DATV reception, instead of using a external home SAT
receiver with rx converters.
Some boards and the Pi needs power. The Pi
needs 5.1Volt. RF switch 12Volt. LO filter/modulator 13.8V, ADF4351 needs
5 volt. These volts are made using a toroid transformer rectified
and fed into 4 small switched power supplies (buck converters). These have
the size of 2x4cm and can be bought through Ebay for €1.50/piece. I
connected these and probed them using a spectrum analyser. Some spikes on
HF to 30Mhz. So I made a casing of double side circuit board to put these
in. Used feedthrough caps and ferrite coils on the in/output for extra
filtering. Nothing seen on the SA with lid colsed.
While looking for these buck converters I stumbled across
some digital voltmeters. For the price of these I can`t even buy the parts
and make time free to build them. For €1/piece I can put these small LED
voltmeters on each output permanently, just because I can.
to be continued.