Re: #bitx40 Q8/Q9 dead - no TX or RX #bitx40

Jerry Gaffke


When directly driving a Bitx40 or uBitx mixer, you definitely want the series blocking cap that Farhan has on the Raduino, one on each output.
Many (most?) of the Si5351 boards don't have this, as they are meant to drive digital pins, not low impedance mixers at reasonably high frequencies.

If you don't have a Si5351 board on hand and want to see something work,
could bring back the old analog VFO by adding L4, C91, C92, and a 10k linear pot at TUNING1.
Usable but rather unstable, there's a reason Farhan eventually went with the Raduino instead.

Jerry, KE7ER

On Thu, Sep 17, 2020 at 07:43 PM, Ryan Flowers wrote:
Evan, you called it! I didn't think to involve the DDS. The output of the SI5341 (clk0) goes straight to ground. Poof! I have another one, I'll swap it in later. I'll also consider feeding the mixer with a network as you mentioned, Jerry. That's a neat idea! I plan on homebrewing my own BITX40 this winter, so that'll be something I'll do with that one. It'll be my first scratch built transceiver :) 

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