Television & Radio Hardware - Surface Plates
Surface plates are also known as wall plates or face plates and are generally the same size as a single gang electrical socket, though more advanced ones with multiple connections are available in a double-gang size. They are used to provide a connection point for a device.
Most professional installers won’t install surface plates as the preference is to run the cable from the aerial or splitter directly due to there being less mess with this method, a faster installation, and also fewer joints. In a home where new decoration is being undertaken, surface plates may be preferred as they provide a neater finish.
As with cable, many stores sell surface plates however, they are typically cheap, unscreened plates which readily accept interference and place it onto the cable causing a reduction in signal quality.
A quality screened surface plate should be installed which protects the cable connection and ensures that the core is shielded through to the connection point.
The most common surface plate is a one-gang size featuring a female connector, into which the male connector of the fly-lead is inserted.
If multiple cables are being supplied to the surface plate, a one-gang twin female connector type can be used.
Satellite connectors most commonly use F connectors, and should use a female type on the surface plate upon which the male end of the fly-lead screws on. A twin output plate can also be purchased if two cables are being supplied.
A one-gang plate can also supply both a single terrestrial cable and satellite cable if required.
Combination plates for television and radio can also be found. These are usually diplexed and tend to use coaxial connectors for both, however the television connection is often male. This means that the fly-lead end being inserted must be female. If using a mast-head amplifier, it is important to ensure that the television side of the plate can pass power through to the amplifier.
As with the diplexed television and radio plate described above, triplexed versions can also be found which accommodate satellite in addition. When using a mast-head amplifier, it is important that the television leg can supply power. Generally, the satellite connection will pass power as this is required by the LNB.
Surface plates also exist which provide two satellite connections on a one-gang plate. The second connector is usually used for a second satellite cable to be added.
In a location with poor signal reception and trouble receiving a broadcast, testing should be undertaken to check that a surface plate isn’t the cause of the problem – particularly an unscreened one. This may mean affixing a connector to the down-lead and attaching this directly to the tuner to see if the signal improves.
A single run of cable with no joints will perform better than one with more joints, however this typically leaves a poorer decorative finish with a cable poking out through the wall. Another alternative which allows for a single run and a surface plate is to buy a cheap, unscreened surface plate and remove the circuit board and socket connection. The cable can then be run inside the wall and emerge through the hole in the plate.
Isolated vs Non-Isolated
As with screened vs unscreened, the other choice to make with surface plates is isolated vs non-isolated.
The non-isolated socket is the most common and generally used in houses. They allow signals to pass back up the cable, which is important in satellite systems where the dish may also receive information from the set-top box. They are also required when a mast head amplifier is being powered through the cable.
An isolated socket is more commonly found in communal situations where there is a need to prevent power and interference being sent back up the aerial cable, potentially affecting a communal aerial system.