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15

Echo™

Technical

technical hotline +44 (0)1268 563720

wireless

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wiring devices

3. SCREENING

Objects made of metal, such as wall reinforcements, the metal foil often

used in certain forms of insulation, or metallised heat protected glass,

reflect electromagnetic waves and thus create what is known as a radio

shadow and thereby a reduction in transmission distance.

The main factors decreasing coverage include:

l

A Transmitter mounted on metal surfaces (typically 30% loss of range).

l

Transmitters with metal frontplates (typically 60% loss of range).

l

Hollow lightweight walls filled with insulating wool on metal foil.

l

Inserted ceilings with panels made of metal or carbon fibre.

l

Lead glass or glass with metallised coating, steel furniture.

Please note: Fire-safety walls, elevator shafts, staircases and supply

areas should be considered as screening.

WALLS

WALLS

Transmitter

Receiver

Repeater

Metal

sheet

Simple example of a possible screening problem.

Depending on the material used to build the walls and assuming the

distance between the transmitters and receivers are within specification,

the illustrations above show a typical screening problem.

For the best range performance a minimum distance of 10mm to

20mm should be allowed from the whole length of the antenna to any

conductive objects, which effectively means the area surrounding the

Switch Receiver module.

Avoid screening by repositioning the Transmitter and / or Switch Receiver

away from the screening objects (radio shadow), or if this is not possible,

by using a Repeater.

4. PENETRATION ANGLE

The angle at which the transmitted signal hits the wall is very important.

The effective wall thickness – and with it the signal attenuation – varies

according to this angle. Signals should be transmitted as directly as

possible through the wall. Wall niches should be avoided.

WALLS

WALLS

Transmitter

Receiver

Repeater

Avoid an unfavourable penetration angle by repositioning the Transmitter

and / or Receiver, or by using a Repeater.

Do not position a Switch Receiver behind a Transmitter. In this

position the signal strength is greatly reduced, even if there is no

wall in-between.

5. ANTENNA INSTALLATION

S

witch Receivers should not be installed on the same wall as the

Transmitter. When positioned near a wall, the radio waves are

likely to be subject to interfering dispersions or reflections.

WALLS

Transmitter

Receiver

In a similar manner to the comment in the previous section, positioning

transmitters and receivers along the same wall will mean the signal

strength is greatly reduced.

6. DISTANCE BETWEEN SWITCH RECEIVERS AND A SOURCE OF

INTERFERENCE

The distance between Switch Receivers and other transmitters (e.g.

GSM / DECT / wireless LAN) or high-frequency sources of interference

(computers, audio and video equipment) should be at least 500mm.

However, Echo Transmitters can be installed next to any other high-

frequency transmitter without a problem.

Receiver

>50cm

>50cm

PC

7. USE OF REPEATERS

In the case of poor reception, it may be helpful to use a Repeater.

The Echo Repeater (K5414R) does not require any configuration (e.g.

programming) and will become operational simply by connecting it to

the mains supply. The new 10AX Switch Receiver/Repeater (K5420R)

is also a repeater when not programmed with any switches. The

various possibilities of use are shown by the illustrations in sections

3. SCREENING and 4. PENETRATION ANGLE.

A Repeater has similar requirements in being positioned as a Switch

Receiver, i.e. it too has an antenna and needs to receive the signal from

the Transmitter and be within range of the Switch Receiver with which it is

intended to communicate.

While planning, it may be worth considering retrofitting the system with a

Repeater.

Only one repeater is intended for use in any single installation. Using

more than one repeater is counterproductive (higher cost, cross-signal

interference, etc).

Echo™ is a registered trademark of Novar ED&S Limited