- Wider bandwidth in SSB filter, so I took it from 2.4 to 2.6 kHz (KI6WX)
- More sensitive VOX (G3RXQ)
- RF-filtering on audio input (G3RXQ)
All of these are modifications to the tighly packed KSB2 board shown above so it took some patience to implement them. The bandwidth modification consists in replacing six ceramic capacitors that were sitting between the crystals. The VOX sensitivity modification is done by adding a pot which can be seen in the image as it sits outside the PCB on the left-hand side. I was lucky to find a mini 5k slider pot in my junk box which fitted in. Finally the RF-filtering was done by adding an inductor of 2.5 mH (right below the 5k pot) and a decoupling capacitor.