[mythtv-users] Big Myth system (2-3 satellite receivers + capture devices, 5 tvs, Samsung DLNA) ?

linux guy linuxguy123 at gmail.com
Sun Oct 9 18:06:00 UTC 2011

On Sat, Jul 30, 2011 at 2:22 AM, Simon Hobson <linux at thehobsons.co.uk>wrote:

> Linuxguy123 wrote:
> >Aside: my home is wired funny.   Most rooms have a single coax from the
> >utility room to the TV locations, supposedly for cable.   Almost all the
> >TV locations also have a Cat5 feed from the utility room.
> >
> >My satellite system requires 2 coax feeds from the LNB to the receiver
> >in order to view HD content.  I'd have to rewire the entire house to get
> >2 coax feeds to everyplace we want a TV.
> Not true - you need two LNB feeds to allow two tuners (ie get the
> "watch one, record another" facility). The HD signal comes down
> exactly the same cable as an SD signal.
> Some devices can be told not to use both tuners (for situations like
> you describe) which will allow all the functionality - but restricted
> to what can be done with one tuner instead of two. Eg, you can still
> record something while watching something else, you can still pause
> live TV, etc - but you can't watch one thing live while recording
> something else, and you can't record two things at once.
> Technically, there is a halfway house supported by some - by
> splitting the LNB feed you can still have two tuners BUT the second
> can only access the same band and polarisation as the first (roughly
> a quarter of what's available).
> The reason for this is, unlike terrestrial where the whole spectrum
> of usable signals comes down the cable together, on satellite some of
> the tuning is done in the LNB. The LNB (Low noise Block Converter)
> shifts the received signal from something very high in frequency
> (well up into microwave territory) down to something that will travel
> reasonably well in a coax cable. It can select one of two bands (low
> and high), and also select by polarisation (horizontal and vertical).
> Thus only about 1/4 of the possible signals are ever present on the
> coax at any time, and so you can't split it without significant
> compromises.


I checked into this.  Any system using the Motorola HDPVR 630 needs 2
satellite feeds to run all the channels on the receiver.  You cannot use a
switch or a splitter.
If you run 1 feed to this receiver, you will not get all the channels.
Ditto for the older 530.

The Motorola HD 605 will run on 1 satellite feed, but it doesn't do PVR.

I have used 2 tuner receivers in the past that would run 1 tuner on 1 feed
just fine.  But not the 530 and 630.

Moral of the story... if you want to use a satellite service that uses the
Motorola 530 and 630 boxes, you need to run TWO (2) coax feeds to every TV

I hope this helps someone.
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