I’m using a Yaesu FT-891 with a DigiRig DR-891 on Linux (EmComm Tools). Frequently the radio starts rapidly keying itself—the TX LED flashes on and off repeatedly. It happens even when all radio applications are closed. If I unplug the black cable from the DigiRig to the radio, the clicking stops immediately. Unplugging the red cable makes no difference. Muting the computer audio and turning microphone/capture levels down in alsamixer doesn’t stop it. Also, VARA’s audio input meter continuously shows excessive input until the black cable is unplugged. A factory reset of the FT-891 stopped the problem once before, but I can’t get that to work again. Has anyone seen this before or know whether this points to the DigiRig, the FT-891 cable, or a configuration issue?
UPDATE: I adjusted the AGC setting on the radio from “Off” to “Fast” and it looks like that fixed it. I was under the impression that AGC should be off for digital modes, so not sure how to proceed from here.
The TX chatter is caused by audio getting into the right audio channel of the soundcard which is triggering PTT by VOX supported by DR-891. This can be caused by some software sending signal there or some crosstalk/interference. In extreme cases this PTT method can be disabled in the hardware by cutting trace between the solder pads lebeled “VOX” on the back side of the PCB.
The AGC reference in documentation pertains to Digirig’s recording device in sound settings of the control panel inside Windows OS. And yes, it should be off there. AGC on the radio is your call.
Thank you for the helpful response. This makes a lot of sense.
So what’s your official recommendation on suppressing the chatter (besides the extreme cases)? Is my AGC adjustment good? Or do you have a more official recommendation?
I’m not quite sure how radio’s AGC setting (pertains to radio’s received signal) affects the audio from the computer (that’s what triggers VOX) - that’s why I mentioned crosstalk/interference.
For proper solution I would check if there is a way to adjust the settings so the audio sent from the system/software only goes to the left channel (some playback device option or balance setting).
Thanks! Grateful for the help!