And I've exhausted my options at the tvheadend forum.
My hdd died, so I'm having to install everything from scratch, but all the other hardware is the same. For some reason I can't get the system to scan the network(s) for muxes. When I try to use the wizard, the scan progress goes to 100% immediately. When I select to force scan (ATSC-C and ATSC-T) nothing happens.
I tried creating a single mux and guessed at the frequenc (there are 5 different ones for each channel) for a couple of channels that do broadcast here, but nothing.
I'm running LibreELEC 7.03 on a R.Pi 3. The Tvheadend backend is 4.2. The TV device is Hauppauge WinTV-HVR-955Q but the web interface gives LG Electronics LGDT3306A VSB/QAM Frontend : ATSC