I'm just getting started with MythTV, and I'm wondering what HDTV tuner and antenna to get. Since I'm not even sure how many channels (if any) I can get, my first step is to prototype an HDTV MythTV box with my old PC (Athlon 1.33 GHz) before investing in a fancy home theater PC.

According to antennaweb.org, several digital channels are within 7 miles of my house, with the furthest one that I care about being 22 miles away. However, I live in Pittsburgh which is very hilly, and I have lots of trees around. Analog reception has always been an issue in this area. Anyway, I'm thinking that I probably need a pretty powerful antenna and tuner card.

Does anyone know how the various HDTV tuner cards compare? Seems like the pcHDTV HD-5500 and the Air2PC HD-5000 are popular. There are several others listed on:

http://www.linuxtv.org/wiki/index.php/ATSC_cards

What I'm wondering is:

1) Which are better at receiving weak signals?

2) Do any of these pay attention to the "broadcast flag" (I know the pcHDTV 5500 does not, and that's a selling point)?

3) Is there a difference in computation load on the PC with these for HDTV (e.g., Air2PC has PID filtering in HW, but it sounds like that doesn't necessarily help with OTA HDTV)?

4) Which are easier to get working with MythTV?

5) Is heat an issue with any of these?

6) All of these just take the digital MPEG2 signal and put it on the hard drive, without any type of "capture" or "encoding" involved, so all would have the same video quality, right?

Thanks.

The pcHDTV-5500 and the HD5000 use the same tuner, the LGDT3303, so they should have similar reception capabilites. The LGDT3302 is that tuners predecessor and it's not as good, so avoid cards with that one. Avoid the NXT2002 also, as the NXT2004 is an improved version of it. There's a thread here which discusses various tuners, but the SNR on the thread is pretty low:

http://www.avsforum.com/avs-vb/archive/ ... 8-p-2.html

If you want analog too, the saa7135 is usually recommended over the cx88 and bt878 chips. I have a pcHDTV-5500 with the cx88 and I agree that analog isn't the greatest on it, but I've never used an saa-based card so I'm just passing on what I've read.

I believe all of these cards pass the broadcast flag on to the software to do what it wants with it.

I'd recommend before you do anything look at two issues

First, look at the issue a different way. Tbe strongest signal that you will be able to get will be from an antenna mounted on the roof your home with no obstructions from hills, power lines, or trees. Think about this it might be a big challenge for you. If you can't get a good signal it is pointless getting a good card because it will just lead to frustration. Moreover if you have a strong signal you can get a low cost card just to test out the waters.

Second, your computer hardware while adequite to record sd and hdtv shows, will only be able to playback sd shows. Look at the posts and you can see that type of hardware that people are using to display hdtv without studdering,,,,,

Your primary focus really needs to be on getting a good signal. I live very near a major airport (O'hare) and reception is hit or miss, so watching OTA ATSC can be miserable.

I'd suggest borrowing an actual OTA ATSC settop box and testing out your reception. (I get a lot of lockups and crashes with Myth when it recieves bad digital signals.) Make sure you can actually get a clear signal. Once you've got your antenna configuration right, return the settop box and get to work on your Mythbox.

I use the Air2PC card and it's very nice - when I have a strong, clear signal - which, unfortunately, is not very often. FYI: I run a 2.2G AMD and it processes a 1080i signal at about 70% CPU usage. I'm also using a 256MB 6600 nVidia PCI-e graphics card, which helps out a lot. But I agree with the last poster - 1.3 won't cut it for HD playback.

When looking for antennas make sure you get one that works with the proper freq band! Most ATSC broadcasts are in the UHF range, but sometimes you'll get one in the VHF range (for example, in Chicago CBS is broadcast VHF). Some antennas won't pick up one or the other.

Thanks. Yes, I realize that my old PC won't work well for playback. I was just going to use it for prototyping, and was going to build a more powerful HT PC if I can receive enough channels.

What about HDHomerun?

It is an external box that works over Ethernet to provide 2 simultanous channels of Over-The-Air HDTV. It does not support QAM over Cable though.

Look here:

http://www.silicondust.com/main/index.p ... roductId=5

At $170 it's a deal as you get 2 channels and almost all cards are single channel. You do need to run Myth 0.20 to use it though as that is the first version of Myth that has the needed HDHomerun as a tuner support.

HDHomerun has just been released. I have one on order and will report back when I get it working.

_________________
ECS 741GX-M Rev 1.0A
SIS chipset
(GQ3131 aka Fry's $99 special)
Semperon 2200
1G RAM
Nvidia FX-5200 svideo out
Hauppauge WinTV PVR-500 MCE (Phillips)
200GB ST3200822A Disk
40GB WDC WD400BB-22JHC0
BTC 9019URF Wireless Keyboard/Mouse

Never saw this device before, Really kewl.

It will be much easier to connect into the network than run cable through the house. Now you got me wanting .20

This should also allow you to keep a better signal since you can install this box next to the atenia, in th attic in my case.

I just need the mvpmc folks to catch up. Don't want to loose tv in the bedroom.

The HDHomerun is also a IR receiver, so you'd lose that functionality if you put it in an attic. Also they now say they support QAM64/256 (unencrypted digital cable TV).

http://www.9thtee.com/hdhomerun.htm

_________________
ECS 741GX-M Rev 1.0A
SIS chipset
(GQ3131 aka Fry's $99 special)
Semperon 2200
1G RAM
Nvidia FX-5200 svideo out
Hauppauge WinTV PVR-500 MCE (Phillips)
200GB ST3200822A Disk
40GB WDC WD400BB-22JHC0
BTC 9019URF Wireless Keyboard/Mouse

Looks pretty neat. Does Myth change channels through the ethernet, or does it need to do an irblaster?

I can't say with 100% certainty but from what I've read Myth can change channels through the ethernet connection without an IRblaster or any Line of Sight.

I've read a few times that people are putting an HDHomerun in the attic so they can have a shorter RG6 run and get a better signal at the tuner.

If anyone knows for certain that the HDHomerun can tune channels in Myth over the ethernet connection please post for the benifit of the rest of us!

Oh, and just so anyone reading knows: The HDHomerun is only supported in MythTV version .20 and higher which means it will NOT work in the latest version of Knoppmyth (Release 5 D1 at time of writting) unless you upgrade myth to version .20.

The HDHomerun does support QAM however you need an SVN build of MythTV for the QAM support and it might also require a firmware upgrade to the HDHomerun.

Martian

HDhomerun *does* change channels over ethernet. It works as "Live TV" also, though the channel changes are slower than with a capture card.

It also now supports QAM if you use the 0.20+fixes SVN version of MythTV.

However, there are issues with actually getting the QAM channels you can find to actually work. Out of over 40 seen only 5 work on my cable system. The cable company apparently works to make it difficult to get QAM working... they'd much rather rent settop boxes!

I have successfully recorded from the channels that do work. But there are still a bunch niggling issues with Myth 0.20 and HDHomerun that make it not quite ready for regular daily use. I expect these issues will be fixed shortly, because all the fundemental pieces are in place and working.

AMAZINGLY with HDHomerun I can reocrd and playback HDTV on the relatively weak equipment listed in my signature. Playback takes about 60% CPU using XVMC. SDTV takes about 12% of CPU to playback. Recording with HDHomerun takes about 3% CPU per channel. There is onl;y a stutter at the beginning of playback and whenever Myth auto expires another show during playback.

_________________
ECS 741GX-M Rev 1.0A
SIS chipset
(GQ3131 aka Fry's $99 special)
Semperon 2200
1G RAM
Nvidia FX-5200 svideo out
Hauppauge WinTV PVR-500 MCE (Phillips)
200GB ST3200822A Disk
40GB WDC WD400BB-22JHC0
BTC 9019URF Wireless Keyboard/Mouse