Building Bitx Part3 – The linear Amplifier

  I built the bitx 20  linear(PA) last week end. My first build of the PA was done on the bitx transceiver board itself.  It done in dead bug style.  When i switched on the power the PA oscillated. I  read several posts on the mailing list and tried some adjustments. Still it was oscillating. Finally, i decides to shift the PA to a separate board and shield it.

The following pictures show how i did wire up th PA.


 Chips of PCB  fixed to a 3’x3.5′ board. The board is divided into two compartments with a piece of aluminum which also serves as heat sink for IRF 510.

 The IRF 510 wired. Since the heat sink is grounded, the drain of the IRF 510 MOSFET was shielded using a mica washer.

 The wiring is almost complete.

  The PA attached to my bitx board.  The oscillation have stopped now. But the power output seems to be low. I am waiting for the next weekend :D)