Quote:
Originally Posted by danielf
Ah, why does it require two separate inputs? My Humax Freeview PVR box only requires one input which comes off a simple splitter to make use of the tuner built in the TV as well as the two in the PVR.
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With terrestrial TV, there is only a one-way signal flow from the aerial to the tuner, so with a splitter, and perhaps an amp, you can run as many tuners as you like off a single aerial.
With satellite TV, there is a two-way signal flow: from the LNB to the tuner carrying the broadcast signal, and from the tuner to the LNB telling it how to polarize itself to receive the channel the tuner requires.
Thus, with a satellite installation, you have to have one LNB, and one cable, for every tuner you want to run.
Except that you can buy 'dual' or 'quad' or even 'octo' LNBs that pack multiple LNBs into a single unit, with two, four or eight cable outputs as appropriate; and you can optionally add a stacker-destacker unit, which allows two tuners to control two LNBs via a single cable, by shifting the frequency used by one of the LNBs down as it leaves the LNB, and back up again as it arrives at the tuner (effectively, stacking two signals into one cable at the rooftop, and destacking them behind the TV).
Having read up on this on a couple of sites, I'm familiar with the operating principles, but also the limitations (they appear to be quite choosy about the quality of installation they will work with) - hence this thread, to solicit opinion from people who have tried them out.