Copasetic Flow

The latest fun engineering problem in ham radio Project TouCans! There's an unhappy capacitor lurking somewhere! I've realized that what I thought was a water intrusion issue is not. It actually appears to be stray capacitance, but where? And is it even stray capacitance? The main, bad symptom Immediately after charging the battery, the radio when hooked up to the new charged brute merely buzzes. The magic fix There's one way around this that works somewhat reliably, and that's to do what's called a 'battery terminal rub start'. This entails the following Attach the radio to the keyer, (which  also sends p9ower up to the radio in the antenna) by plugging its Ethernet cable in. The batter is disconnected at this state. Attach the keyer's negative terminal wire to the negative battery terminal Do not attach the radio's positive terminal wire to the battery. Intead: Rub the edge of the keyer's terminal wire on the gnurled surface of the positive bat...

  Squigily audio in our homebrew ham radio rig? Capacitors! This extends the capacitor post from last week. This week, while adjusting the Tuna Topper amplifier bias after a run-in we had with an unexpected rain shower, I put capacitors across the dit and day switches on the keyer. The dit capacitor was particularly useful because with the amplifier bias set above a certain level, the keyer chip would immediately reboot when the dit key was pushed. I'm assuming RFI transients were punching through to the little processor, befuddling it in the process. Today, the kid—Diaze—and I changed the battery from a D cell pack to a LiFePO4 battery. The extra bit of punch provided by the nicer battery meant we had to turn down the bias on the TunaTopper's onboard pot just another quarter turn or so. The resulting keying sidetone over the headphones was less than esthetically pleasing though. When Diaze sat down to key out a CQ, the buzzing and squiggly sounds were too much for her. A rec...