Dvbv5-scan Initial File

dvbv5-scan --config dvbv5-scan.conf

# Scan using a system-provided initial file dvbv5-scan -o mychannels.conf /usr/share/dvbv5/dvbv5-scan/dvb-t/uk-CrystalPalace dvbv5-scan initial file

Your antenna might be disconnected, or the initial file's frequencies are outdated. dvbv5-scan --config dvbv5-scan