Always check your connections. You would be amazed at the possibilities. I posted this on another thread, but it might be useful to readers here.
Ah, Mux 2, signal degradation and F plug threaded connectors. They are called F-connectors because of the foul language they provoke.
It can be difficult to fit F-connectors (F plugs/threaded connectors) properly. I suffered all the agonies of the damned with the power supply unit for a masthead amplifier, and even a professional TV repair man soiled the mattress when he had a go.
I moved into a new place and found an old power supply unit there. The thing looked as if it had been built in the Seventies: the brown coaxial lead from the external aerial (through the wall) was connected to the unit via the bit of exposed copper wire at the end, which was screwed into a connection inside the unit. Think of the little screws and terminals inside a standard electrical plug: that sort of arrangement. A second lead (again screwed in) went to the Freeview box.
I kept getting channel degradation, particularly on Mux 2 channels, and if you moved the unit more than slightly you could lose the signal completely.
The unit finally expired, and I bought the modern upgrade, which had two female thread connectors. You would think that this would be a five minute lock-and-load job, but no. Ill spare you the full horror story, but there are a few points to bear in mind.
If you are stripping the end of a coaxial cable to insert into a thread connector, its best to use a very sharp cutter to cut the end (the bit which goes in) at a 45-degree angle, so that it is more of a point. This gives a better fit. Trust me: it was obvious. However, be careful with this: its very sharp, and you can easily scratch yourself or get a tiny shard/splinter of copper in your skin.
Secondly, some people cut off the thin copper wires known as the braid, on the outside of the coaxial cable, underneath the insulation cover, when they expose the end of the copper wire/thread at the centre. Do not do this: its there for a reason and essential to conducting the signal. Bend it back along the cable, spread it as evenly as possible, push the cylindrical metal connecter sleeve/fitting over it and, only then, trim away any loose bits which are still protruding from the bottom of the metal sleeve.
Other than that, ensure that the sleeve is fitted tightly onto the cable, so that the cable does not fall out, leave about 2mm-3mm of the sharp copper wire (the pin) protruding beyond the end of the metal grip which you will screw onto the outside of the female thread connector (think of a large needle sticking out of the business end of a sink plunger or dalek sucker and going into a lemonade bottle: thats how the setup looks). Then screw the cable onto the connecter.
Use a Mux 2 channel to test the signal, as these are the first to degrade and the last to give a 100% quality reading. At least the wretched vulnerability of Mux 2 acts as an early warning that trouble is brewing for all of the channels.
The cat observed the proceedings with great interest, occasionally slapping a paw to her forehead in despair at the incompetence on display.
Two good links with photographs:
Satcure satellite dish LNBs digital TV aerial information
http://www.avforums.com/forums/inte...witches/470017-guide-how-fit-f-connector.html