Planning A Wireless Application; Noise; Networking Guidelines; Frequency Analyzers (Sniffers) - Siemens Bewator Entro Series Installation Manual

4

Planning a wireless application

4.1

Noise

4.2

Networking guidelines

4.2.1

Frequency analyzers (sniffers)

Siemens AB
Security Products
Good planning is particularly necessary for a successful wireless installation. This
section describes what to consider before the installation is started.
Read Appendix A regarding considerations for RF communication.
If hard-wired door equipment is included in the site this should be installed and
tested first. You will then have a PC available with software for checking wireless
units.
Then follow section 8 Installation to see how the practical configuration is per-
formed.
It is advisable to try to identify in advance any noise sources that will degrade the
radio signal. Bewator Entro wireless networks use the ZigBee radio technology so
take care if other ZigBee services are installed nearby. Other sources of interfer-
ence include:
Wireless computer networks (WLAN) may interfere and the frequencies for this

and the SR35i must be investigated and adjusted.
Motors, high voltage equipment or microwave equipment may interfere. Do not

mount any wireless units near these.
Avoid mounting routers in kitchens or similar because microwave ovens will in-

terfere.
Metal will attenuate but also reflect the signal.

Thick concrete structures usually include steel reinforcement bars which absorb

and scatter the signal.
Human beings also absorb and reflect the radio signal. If you hold a unit its sig-

nal will change.
Wireless units operate in up to 15 frequency channels (11-26) in the frequency
band 2.405 to 2.480 GHz. The SR35i may be set to avoid channels used for other
services. The most likely sources of interference in the 2.4 GHz band are wireless
Ethernet networks (Wi-Fi/802.11), Bluetooth or other systems based on ZigBee.
Take advice on channel selection from your IT manager.
A wireless unit should not be installed less than one metre from a WLAN access
point using the same frequency channel or less than 10 metre from a 3G/UTMS
base station (e g in a shopping centre or similar).
Third party products are available i e frequency analyzers, sniffers, enabling a PC
to be used as a simple tool to scan for activity on the same or adjacent actual net-
work frequency band(s).
Planning a wireless application
15
03.2014