开云体育

+1.? Maybe +1000.

I believe this Auto-gain is what bit me last year during Field Day.? I had some RF intrusion into the Raspberry Pi's audio dongle, with the net effect that keying up would cause the transmit volume to dive to zero, and apparently beyond.? Simply rebooting the Pi did NOT fix the problem nor could I even go into the Mixer to change it, as the now-negative transmit level apparently caused an internal fault of some kind.? I had to re-flash the entire SD card from a backup copy to restore the Tx audio.? Good for one short transmit, then re-flash again.? If I could catch the volume dive in the Mixer with my mouse before it got to zero, I could keep it from getting locked out.? That got old fast.

After the dust had settled I found the following commands (this from a note to self on my Field Day Pi):

In terminal, to save the current audio file settings as a file use..
"sudo alsactl --file /home/pi/alsa.backup store"

To restore...
"sudo alsactl --file /home/pi/alsa.backup restore"

If you don't need the file and just need to store and restore on the system..

"sudo alsactl store"
"sudo alsactl restore"

I've since repaired the cabling to remove the RF intrusion issue, but left the above file text and backup file in my home directory as a reminder.? Note that the typical TRRS audio dongle has the Mike-in line on the Sleeve connection, which is usually where the cable shield is connected.? Don't do that...

Fingers crossed for some FT-8 contacts this year.?

Greg? KO6TH

What David Ranch said.? Good chance Auto-Gain is enabled on your USB soundcard.? I've used a ton of Syba and other cm108-based soundcards which always have auto-gain enabled by default.? Easiest way to disable it is to run "alsamixer" in a Terminal, hit the F6 key to choose the correct soundcard, then F4 to display the Capture controls.? Then use the arrow keys to go to the auto-gain slider and hit the "M" key to toggle auto-gain off.? Now the "Capture" slider will adjust your mic-input levels.? Then hit F3 to go to Playback controls and lower any "Mic" sliders to zero.? The Playback "Mic" slider is for playing audio back thru your audio-out that is being recieved on the mic-input... not desirable for ham digi-modes.?

On a Raspberry, alsamixer will save its settings when you exit alsamixer. Some other Linux distros require running "sudo alslctl store" in a Terminal? after exiting alsamixer to save the new settings.