the thing is, it depends how many feeds you want. If your dish has a single LNB, then you have a single tuner box, and you can watch/record a single channel. (You may be able to play a recording while recording something)
If you want a two-channel recorder, eg sky+ type arrangement, then you need a dual-feed LNB. Depending on your house internal wiring therefore, you may need to conceal another cable somewhere.
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i re-read your first post - you have freeview, not freesat, dont you.
I have a HDD DVD Recorder to record freeview programmes, which I can then edit out adverts, and archive to DVD if I want. Its SD, but I use it lots, and have hundreds of DVDs as a result. (Normally I use Sony DVD-R blanks at about 20p each, in spindles of 100)
Occasionally, I would like to record two things at the same time, but it isnt so much of an issue, tbh. Series record, and things like that are invaluable.
I also have a humax freesat HD player (not recorder) - If I want to I can mess around with timers manually, and record from the freesat, but I dont very often. I find BBC HD not much different in quality from BBC SD, and the content sadly lacking - but ITV HD is excellent, and seems to me to have a higher bit-rate - and all ITV1 is broadcast on ITV HD
The only other HD channel, is more of a demo thing - a german channel called LuxeTV - and it isnt available on the main EPG - but it is available on the manual channel list.
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When SKY (or anyone else) install a sat system, they will bring black cables into your roofspace and drop them into the room where you want them. You will therefore have one or two cables that will need hiding/covering in some way. If you need to redecorate, consider channelling out and burying a couple of sutiable satellite cables.
Also, note that a condition of taking sky, is that the skybox MUST be connected to a phone socket for the first year.