It's fairly easy if you're ok on a ladder.

Get a quad LNB for a little future proofing (and a 60cm dish to reduce
the chance of signal breakup in bad weather).

Make sure you put everything together at ground level with U-bracket
bolts only just tight and with various bits at roughly appropriate angles.

Drill into brick and not mortar.

Run decent coaxial. Two to the room in which you are likely to put a PVR.

Get a cheap satellite meter to help with alignment (~£7 on Ebay, £5 for
mine - used only once!).

Plug the coaxial into the Freesat box (box turned off!!).

Turn TV and Freesat box on in a position where you can see the Freesat
signal strength display.

Move the dish side to side until the meter shows a reading and you can
hear a tone. You know when you've got the correct satellite when both
signal strength and signal quality rise. If only strength rises, you've
got the wrong satellite.

Once you're on the correct satellite move the dish side to side very
slightly until you get the maximum meter reading (you might have to turn
the gain down on the meter a few times as it maxes out).

Now move the dish up and down until, again, you get maximum strength.

Now rotate the LNB until, again, you get maximum signal strength.

http://www.dishpointer.com/ will give you the angles you need and will
help with finding the correct direction in which to point the dish as it
gives you a 'line on the ground' for which to aim if there are no other
dishes visible.

http://www.satcure.co.uk/ for more information and bits and pieces.

HTH

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F