Cable for TV aerials
- Use only CAI approved co-ax. Inferior types lead to picture freezes with digital reception, and interference on analogue TV.
- Don't be tempted to re-use leads already in place. Old non-CAI cable is sufficient for analogue, but not good for digital, and useless for satellite.
- Never use co-ax that is not designed for TV use. Some baseband co-axes look the same as TV aerial wire, but these cause heavy degradation, even with analogue TV signals.
- Use only black cable outdoors, other colours slowly degrade in sunlight.
- Don't kink the cable when installing.
Choice of cable
This article gives a guide to choosing a suitable cable for a particular application.
As explained in Co-ax Cable, colour does matter when used outdoors. Only black cables are good for exterior use, other colours degrade in sunlight. The black pigment blocks the UV that does the damage.
- Avoid sharp corners and kinks in the cable.
- Avoid squashing the cable
- Avoid long unsupported runs of cable, eg across roofs
- Clip exterior vertical cable runs frequently. A climbing plant can put a good deal of weight & wind load on cable.
- Fitting exterior vertical cable runs partially behind a downpipe makes them less visible and ensures load sharing of climbing plants, reducing strain on the cable.
- Use the suitably-sized round cable clips designed for mains use. Avoid using clips which deform the cable, as occurs with some non-mains clip types.
- Avoid using 50 ohm cable. It looks like just TV cable but is totally unsuitable. It gives heavy signal loss at TV frequencies.
- Where cable enters a wall, it is better to turn it downward, and then form a half loop so that water on the wire runs out from the wall instead of into the hole.
| | <--- cable | | _ | (_) <--- hole in wall | | | | <--- J shaped wire loop \___/
If drilling from inside with a SDS Drill to take great care with the exit hole - its very easy to blow out the facing of brick or stone leaving an ugly lump missing from the wall: