U02 - WebWSPR:
An important point in WebWSPR is the automatic detection and installation to make it easy for unexperienced users, as far as it is technically possible.
This includes the automatic detection and adjustment of the sound card. In the best case, you just plug in a USB sound card and you do not have to worry about anything.
Here are some hints:
WebWSPR automatically finds the first sound card suitable for WSPR. This is usually an external USB sound card or a USB connected ICOM radio.
The HDMI sound built into many computers is ignored. It also automatically detects a mono or stereo card (stick).
If the sound card is found and ready for use, the sound symbol in the upper left corner lights up green, otherwise red.
the levels are chosen so that they usually fit. The recording level is displayed on the yellow bar, a value between 5% and 80% leads to good results.
Overload (level indication 99%) may occur when you feed a high level in the microphone input of an USB stick. In this case, a voltage divider (potentiometer) must be connected.
If you want to adjust the level manually for some reason, you can do that in the Linux console by typing:
then press F6 and select the USB sound card. Then press F5 to show all controls. You can do fine adjustments here.
Alsamixer settings are lost after switching off. If you want to save them permanently, enter:
sudo alsactl store
Only (!) when using the prepared Raspi image you have to copy these settings additionally on SD card, this is done by entering: