[mythtv-users] HDHomeRun Vs. PCIe tuner card?

[Brian Wood]

On Monday 17 August 2009 09:45:36 Eric Sharkey wrote:
> On Mon, Aug 17, 2009 at 10:55 AM, Brian Wood<beww at beww.org> wrote:
> > A "powered splitter" is simply an amplifier with an attached hybrid
> > splitter. Whether it is the best solution for you would depend on whether
> > you rally need an amplifier
>
> When I moved into my current house about 4 years ago, I was feeding a
> Series 1 TiVo, a PVR-150 in my mythtv, a cable modem, and a VCR.  The
> signal was just barely watchable and getting a ~$20 4-way powered
> splitter helped quite a bit but I found that I couldn't get the cable
> modem to work reliably through the powered splitter.  I ended up using
> a two way unpowered splitter to split out a line for the modem, and
> then the powered splitter to  feed everything else.

You might try a directional coupler instead of a hybrid splitter to feed the 
cable modem. My cable company does this exclusively, and will not use a 
hybrid splitter to feed a docsys modem.

You also have to use a splitting device that is bi-directional, since a cable 
modem needs a two-way path, while TV sets etc. do not.

Unless the powered splitter had a return path, even with little or no gain, 
I'm surprised the cable modem worked at all.

>
> Today, I've disconnected the VCR, added a DCH-3200 cable box and an
> HDHR using both tuners.
>
> What I've found is that the powered splitter seems to be actively
> harmful to the HDHR, cable box, and (when I tried it) the digital
> tuner in my TV.  I still use the powered splitter to feed the PVR-150
> and TiVo, but everything else goes through unpowered splitters.  For
> some reason, it seems to really mess up digital signals while
> significantly improving the quality of analog signals.  A more
> sophisticated splitter might have different results.

Possibly. The digital channels may be running at a different level than the 
analog ones, so you might be overloading the amp with the digital channels.

Make sure any unused outputs are properly terminated, or you can get ringing 
or other problems similar to multi-path with antennas, these problems are 
more serious with digital signals.



-- 
Brian Wood
beww at beww.org