Well, you have two problems.
# You're not receiving data from the dongle.
# You have a user auth error (this is easy to fix).
> 1. How to install and use w_scan on osmc?
dmesg and w_scan both require ssh access.
Login via ssh and use
sudo apt-get update && sudo apt-get install w-scan netcat
Once installed do.
sudo dmesg | netcat termbin.com 9999
This will paste your dmesg to termbin & output a url
sudo service tvheadend stop
w_scan -cCZ -ft
I assume you're in the Czech republic? Change CZ to your country code otherwise.
It should output signal information, you should see signal OK during the scan, make a note of the signals it OKs. Once the scan has completed, restart tvheadend.
sudo service tvheadend restart
Paste the dmesg link here.
