Tvheadend

I have an HDHomeRun Duo, and it works great with my OTA antenna just going right into Plex (no TVH), but there are a few channels that don't come in great. If I plug my HDHR into my cable connection, it sees a couple dozen channels, but they are start at channel 5000. I can play these in VLC just fine but it shows "Unknown" in the setup page for HDHR. Ultimately my goal would be to able to map these so that I can bring them into plex without problems, so I started playing with Tvheadend last night.

I tried a few different things, but when I created a network for ATSC-C, added some default mux presets (us-Cable-Standard-center-frequencies-QAM256), and ran a scan, it'd only show 2 'services'. And when I tried to play either of those, I'd get an error in the console: "service instance is bad, reason: No descrambler".

I then tried to create my own Muxes, and based it on some other scripts I found: https://pastebin.com/hbMGXVhF

When I ran the scan again, it found the same 2 services and had the same error when I tried to play them.

I'm pretty stuck now. I'm not sure where to go from here. Can anyone offer any suggestions? Here's the scan that hdhomerun_config ran: https://pastebin.com/rSbtbNYd