In the last entry about my new project, a micro multibander for QRP SSB HF use, I referred on the circuits of the Si5351 VFO, the microcontroller, OLED module an the other digital circuits controlling the transceiver.
This is the practical side, now: All the digital circuits are placed behind the front panel. This is for practical (to save space in the main cabinet) and electronic reasons. By keeping the digital leads as short as possible you make it is easier avoiding hum, noise and other unwanted radio signals penetrating into your analog circuits, mainly the reciever.
This is how the front section looks from the user side:
The 3 potentiometers on the left (still awaiting suitable knobs) are for audio volume, receiver gain and mic gain. A switch will allow to switch the AGC from fast to slow. The S-meter has been taken from an old CB mini radio. All does not fit that much, some mechanical work still has to be done. 😉
This is the module taken from the side. All electronic stuff is mounted onto a 8cm x 6cm double sided veroboard. I use M2 spacers of various lengths to keep the “subboards” in place, like the Si5351 breakout, that you can see in the middle of the picture. These spacers are available from Chinese vendors on ebay and help a lot to build very compact electronic stuff. All joints and bolts are kept in M2, too.
The module is finished with a 1.5mm aluminium board where the plugs for the connectors are fed through. These connectors will be equipped with home-made plugs (1″ technology) and then connected to the respective parts of the analog circuits like receiver or transmitter.
Here is another view of the lateral arrangement: The old-style S-meter stripped from an old HANDIC-brand CB radio was purchased on ebay for a few Euros. There ist still a lot of old CB stuff there, giving enthusiast homebrewers a large stock in interesting electronic and radio-related material.
(To be continued)