So I'm currently attempting to cut the cord. As part of that, I'm trying to set up an antenna, attach it to an HDHomeRun tuner, and record from it using my Synology running Plex as a DVR.

Well, it's been ages since I've dealt with OTA signals and reception issues.

I've found a place in my home where the antenna won't look ugly and where I can get an ok signal. It's definitely on the edge but I get the big 4 and PBS, which is pretty much all we wanted. I found this positioning using the coax cable that came with the ANTOP brand antenna (model AT-400BV).

This evening I decided to install the coax permanently, but I need a little more length so I used my own cable that I use for work. It's a quad-shield RG6 cable, and seems higher quality than the 40' cable that came with the antenna. I'd estimate that I ran about 60' of my cable.

But I've lost channels.

Not all of them, but when I connect my cable I'm getting about half the channels I did before. When I switch back to the included cable, I get those channels back. What gives? My coax isn't running past any power cables, so interference shouldn't be a problem. And it's quad-shield anyway so that should mitigate that. The antenna comes with a required in-line amplifier which I've been attaching to both lines in my tests.

So what's going on here? Is my cable bad somehow? What should I do?