GRBAlpha - How to use digipeater or DNxD - 10. About sampling rate

When you use a software modem like Direwolf or Soundmodem, you may have difficulty to decode signals. As I mentioned in the Section "06. RF & AF input level", you need the signal level as more than S2. Even when you get this level, you do not have enough result. In this case, try to check your settings about sampling rate.

In case of Windows system, you have to check the system sampling rate at first. Open the control panel of sound on your PC, then check  the detail property of microphone, line-input, line-out, and speaker. You will find the sampling rate there like "16bits, 48000Hz".

The sampling rate should be "48000Hz" at least in case of 9600bps. My Ham friends, JA0CAW and JA5BLZ, pointed me it out.

Additonally, I recommend you to set the sampling rate of Direwolf or Soundmodem as more than 48000Hz.

In case of Soundmodem, set the "TX SampleRate" and the "RX SampleRate" as "48000", or more, in the "Settings" window of "Sound Card" that I mentioned in the Section "07. Settings of soundmodem".

In case of Direwolf, add "ARATE 48000" in the "direwolf.conf" file like as:

#############################################################
#                                                                                                                      #
#                               FIRST AUDIO DEVICE PROPERTIES                          #
#                                        (Channel 0 + 1 if in stereo)                                   #
#                                                                                                                     #
#############################################################
ARATE 48000