Quick tip if you're trying to get a networked TV tuner like the SiliconDust HDHomeRun PRIME working on the same jack with a MoCA box -- short answer for the impatient among you is you're going to need a diplexer. You can get something like this one which splits the signal into 5-860MHz and 950-2150MHz ranges, or something like this basic satellite/antenna diplexer from Radio Shack.
Plug the coax from the wall into the input of the diplexer, and send the lower range (which is labeled VHF on the basic diplexers) to the HomeRun and the higher range (which is labeled VHF on the basic diplexers) to the MoCA box and everything should work. Without this, when I was going wall -> MoCA box and MoCA box -> HomeRun, networking worked fine for me but there was no cable signal being sent to the HomeRun.
So longer explanation for those of you who follow my home networking trials and tribulations, with the threat of Moxi going away (though this has been put on hold indefinitely) I decided to investigate other solutions and I wasn't at all keen on spending $1.7 trillion on TiVos. (OK it's not really that much but it adds up quick for a three-room setup when you get the lifetime subscription.)
My brother pointed me to a deal on an Acer Revo HTPC that was too good to pass up, so I got that and an HDHomeRun for the tuner. Yes, I know, I'm always talking about how much I hate Windows, I'm an open source bigot, etc. etc. but the reality of the situation is that I'm not the only one in my house that watches TV so I have to at least be semi-congizant of ease of use, and much as I keep saying I'm going to build a MythTV box, every time I investigate things like remote controls, backend vs. frontend boxes, etc. it seems to get complicated rather quickly. If it were just me watching TV I'd go for it, but some people in my house just like to turn on the TV and have it work without any hassle. (Can you imagine?)
The good news on the MythTV front, however, is buying the Revo freed up another desktop PC I was previously using just for PlayOn and PlayLater so I'm going to put MythTV on there, and from what I've read it works with the HomeRun! At least that way I can maybe have MythTV in the man cave and have something more easy to use (in theory anyway) in the living room.
Back to the networking piece of this. When I had Verizon FIOS TV I had been using MoCA for networking and it worked great. When I switched from Verizon to Comcast, however, the MoCA didn't work in the rooms where I needed a cable TV signal and I didn't do enough research at the time to figure out why. I assumed it was a signal strength issue so I tried some amps but none of them worked.
Instead of digging into that more at the time I moved to powerline networking and while it's been decent overall, it's never been as solid and fast as the MoCA was and it wasn't working very well for the Revo to talk to the HomeRun. The picture would get jerky pretty often or the audio and video would get out of sync, so that wasn't going to fly. (That said, powerline networking worked quite reliably for streaming HD from the main Moxi unit to Moxi Mates in other rooms, so don't shy away from it based solely on me switching back!)
This prompted me to switch back to MoCA since that had worked fantastically well for me before, but I again ran into the issue with the cable signal. This time I did my homework and discovered that most people that were having this problem resolved it by using a diplexer, and luckily that fixed things for me too.
Next up is putting more RAM and a bigger hard drive in my other desktop machine and trying out MythTV so when I get a chance to do that I'll be sure and share how that goes.