Yep. I agree 100%. There's something else that's hinky, and I don't know what it is. I need to do more testing before I power this thing up again. I think 12V got somewhere it shouldn't have. It might

#bitx40

The stock Bitx40 has few wires between Raduino and the main Bitx40 board, just 12v DC to power the Raduino's 5v regulator, that Si5351 out through a series cap, and a couple grounds. The series cap he

#bitx40

The Plot Thickens! It ate another SI5351 board :-/ I had assumed that I had killed the board, but I think the death goes deeper somewhere, as now that board is dead. And, the arduino might be dead too

#bitx40

The QRP Labs synthesizer kit does not have series caps on the output. This is typical of Si5351 boards, if you want series caps to level shift such that the signal is centered on ground, then those ca

#bitx40

Had a 10 minute work break (working from home is great!) and a new Si5351 is installed with a 100nf decoupling capacitor between the clock output and the board. I'm now getting DDS sounds again, but s

#bitx40

Jerry, Evan thanks again! I'll check out the blocking cap. But, this is a QRP Labs board made for radio, not the adafruit board. As for the drifty varactor VFO... No thanks! Been there done that. This

#bitx40

Ryan, Glad you found it! I would echo what Jerry suggested to add the blocking capacitors if they are not already on the board (since it is an AdaFruit board, those are often designed for logic circui

#bitx40

Ryan, 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,

#bitx40

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 w

#bitx40

Thank you for the answers, gents! It's possible that I messed up my DDS in the process- that would definitely explain it. It's a QRP Labs Arduino dev board and SI5351 board, and a regular Arduino runn

#bitx40

Syd, Building off what Jerry said, and know remembering the Raduino connector pinout, I think you are one pin off on the Raduino to DDS1 connection. On the Raduino every other pin is ground around the

#bitx40

Actually, not much need to remove Q7,Q9,Q9 if doing the quick fix. Remove R70, short across C71 to ground T2-1, cut the trace from Q7 to T2-6, then add Farhan's 4 resistor network between Raduino and

#bitx40

Ryan, Well, I haven't posted in some time as well. A possible quick fix: remove Q7, Q8, Q9. Drive the mixer exactly as Farhan now does in the uBitx with a 4 resistor network at the transformer. The on

#bitx40

Ryan, The only way that I can see a 0 voltage on the base of Q9 is if the DDS1 signal is shorted to ground. You said that the 5v regulator for the Arduino bumped something. Maybe the DDS source is not

#bitx40

Hi everyone, it's been quite a while since I posted here! The short version: I have no receive, and Q8/Q9 show now voltage on the base or emitter. Collector has the correct voltage, about 9v. I replac

#bitx40

Scott, Mike, Emails sent. Thanks. Ted K3RTA

#bitx40

Ihave a Bitx 40 too that’s available. QRZ Wb7AVU

#bitx40

I have one that is 2 or 3 years old. It's in a rather large case and I also have a spare board with some parts removed, a spare microphone, extra mic elements and more odds and ends. It works fine, bu

#bitx40

For a project, hoping to find an older model with 10-turn POT for tuning rather than a raduino (if i understand the lineage of the radio correctly). Anyone?

#bitx40

Bill, I have several wall warts that are solid state. One is 12V, 1A. Others are for cell phone charging. A well-equipped ham has a bag or box with a collection of wall warts. {;-> Bob — KK5R

#bitx40help #bitx40 #noise