[mythtv-users] How to best deal with Comcast's "Improved" Lineup?

Douglas Peale Douglas_Peale at comcast.net
Wed Jul 21 21:02:34 UTC 2010

On 07/21/2010 01:22 PM, Brian Wood wrote:
> On Wednesday, July 21, 2010 01:34:07 pm Douglas Peale wrote:
>> You won't know until you try, but trying is really cheap. just get a 2 way
>> splitter and use that to combine the signals, and give it a try. If you
>> don't already have a splitter, it will cost you about $5.
> It would be better to use directional couplers to do the combining, and not hybrid splitter/combiners, as you would get 
> much better isolation between the two devices being combined. The isolation spec on hybrid combiners is based on the 
> assumption that each port is seeing precisely 75 ohms, while with DCs the isolation isn't dependent on precise 
> termination, and the isolation is better in any case.
> The problem is that you would lose more signal by using DCs. I don't know what level the devices put out, it would have to 
> be at least +10 dbmv. or more, assuming 8 db. loss DCs.
> Might not work well, due to insufficient output levels, I just wanted to point out that DCs make a much better combining 
> network than hybrid splitter/combiners do.
> A couple of DC would run about $10 or $12, more than a splitter, but technically a better solution.

1) a directional coupler is more expensive
2) a directional coupler is harder to find
3) a directional coupler may not be necessary
4) a directional coupler will not help if the source is crappy and mucks up adjacent channels.
5) he still won't know until he tries.

Do the simplest cheapest test first. If that does not work, then start worrying about alternatives.

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