I’m stumped as to what might be causing intermittent failures of the USB audio device on my MacBook and could use some pointers as where to look next.
My setup:
MacBook Pro M1, macOS 15
Digirig v1.10 with RS232
Kenwood TS940s with the Piexx serial interface
WSJT-X
(And I’ve tried w and w/o MacLoggerDX being involved)
Kenwood 13pin audio cable
RS232 DE-9 connector
The typical scenario is that I’m reliably able to send CAT commands and have the software change frequencies, etc. Audio reception will usually work reliably, but more often than not, I can’t get the software to send any audio out the Digirig. When it does work, I can usually get it to remain functional. But when things aren’t cooperating, it seems like there’s nothing being send. PTT isn’t reliably working – sometimes CAT commands will work, but this morning I was only able to send data using VOX control.
I’ve created an aggregate audio device in the macOS MIDI setup, consisting of the USB audio device plus the macbook speakers, to give me confidence that wsjt-x was indeed sending something. This afternoon I watched the USB device disconnect and reconnect on the computer, but no idea what’s up.
Eventually, the serial interface will be unloaded, and I have to disconnect the digirig to get it back.
Things I’ve tried:
keeping transmit to 5W
using a USB isolator
Different USB cables
Ferrite beads on both ends of the USB cables
Moving the digirig and digirig cables to various locations on the rig and keeping them away from the coax antenna cables
Ensuring any lingering and legacy SiLabs macOS driver are uninstalled
I have no reason to believe it’s an issue with the digirig, but don’t know what else I can try. Any advice?
I haven’t yet tried a different serial adapter but will work on that. I have two of the Prolific-style ones floating around but I’ve misplaced them. And one’s counterfeit which is blocked by macOS these days. The Piexx board (which is a drop-in replacement for the original Kenwood option) comes with notes that FTDI serial adapters work better, so not sure if the other models I have would even work.
Hmmm… somewhere around here I have a USB-C multimeter. Maybe if there’s weird RFI involved, it would manifest with spruious readings on it. The problem with the USB-C meter is that it’s black with black accents, readily blending into surrounding black-on-black USB flash drives, and similarly colored USB everythings.
Oh poop. Another datapoint that I’ve ignored is that the incoming audio is seriously high and I have to turn down the volume in the MIDI Setup app. I hadn’t yet opened up the Digirig to unsolder the attenuating pad. Could the high levels on input be somehow related? I’d have thought the answer is “no” because when it works, it works great. But maybe that’s not a reliable truth.
Unfortunately, I’ll be traveling for the next few days and won’t be able to test out these theories til Wednesday. The Kenwood had belonged to my uncle; he gave it to me about 14 years ago and only this year did I begin the path to getting it online. After upgrading the power supply and other work, I could have just bought a new radio with USB support, but then I’d have to explain to my wife why I’ve been holding onto the TS-940s for so many years.