[mythtv-users] HDHomeRun(s)

Brian Wood beww at beww.org
Thu Jan 14 18:58:48 UTC 2010

On Thursday 14 January 2010 11:48:28 am Kirk Bocek wrote:
> Johnny wrote:
> > I am getting out of my element here but I don't think that is as
> > absurd as it initially appears. The old analog cable splitters only
> > passed up to 800 MHz (I think). When the cable cos started carrying
> > internet service, phone, digital cable, etc. they utilized more
> > bandwidth and require 1000 MHz splitters. The digital refers to the
> > fact that it can pass the digital cable services.
> I'll second that. I had what seemed like a technically capable cable
>  company tech come out some years ago. He made a point of saying that you
>  need to use splitters that go to 1Ghz. Of course of I have *stacks* 800Mhz
>  and 900Mhz splitters.
> Now if someone could explain to me what the ratings on the "Satellite"
> splitters mean. They're labeled as going to something like 2350 Mhz. Do
>  they behave differently than the 'cable' splitters?

The output of a satellite dish's LNB (Low Noise Block converter) is L-Band 
(approx. up to 1.4 Ghz.), so the "splitters" often split "normal" frequencies 
from the L-Band ones. They don't split all frequencies equally, though some 
do, it depends on the application.

Now, as they have gone to multiple satellites, the extra channels are carried 
even higher off the LNB, hence the 2.35 Ghz. requirement.

Satellite passives may also have to pass DC, used for switching the polarity 
or the satellite, in order to get the correct LNB and polarity, notice that 
most modern sat installs have a "switch", controlled by signals from the 
receiver, which the passive has to pass.

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