Remember that device that was off-frequency? The one that I was going to just let be off-freq and deal with in software on the receiving end? The one that's functioning incorrectly but I'm going to ignore that minor detail and live with it?

Yeah, I couldn't live with it. (I shoulda seen that coming.)

The conversation in my head went something like this.

"Logically, the problem must be in the transmitter," says me. "The transmitter's discrete. There doesn't seem to be any initialization sequence configuring it. So it's got to be a hardware problem, and if it's a hardware problem, it might be correctable."

So, slightly inebriated, I decide it's time to poke at the hardware. "Maybe I'll desolder the transmitter and harness it." Pause. "I'm not sure what that buys me. It'll just be off-frequency outside of the sensor." Sip. "I could make it transmit more frequently, at least. Or maybe pull out the scope! It doesn't go up that high, but maybe I'll find that they put in the wrong crystal or something."

A short break later while I refilled my beverage of choice, I started thinking about what crystal it is. "I could open another one and look at it. That's probably the easiest way to make sure it's got the right crystal. And then when I desolder it, I can take care of this nasty ugly blob of solder on the crystal leads on the transmitter." Sip.

My brain signals something that I'm not quite paying attention to.

Sip.

A blob of solder. "Huh, they soldered the humidity sensor in really poorly. Glad I could fix that and it worked fine." Sip.

A blob of solder. "And here it is, but not nearly as badly, on the transmitter. Good thing too, they might have shorted out something important that made it function improperly."

Perhaps you've figured it out by now? Cause I was clueless until about that point - yes, indeed, the crystal was poorly soldered on to the transmitter.

30 seconds of running it downstairs and resoldering the crystal later, and in a fashion befitting overly attitudinal chefs, *BAM* - we're stable, on-frequency, no drift at all.

Aah. I gotta remember how useful a little downtime is more often.