User's Manual

l. Selecting Wireless Network Equipment locations
WNI Master location
The placement of the 90310-A/B and its antenna is critical. Antenna placement and relative polarity
(vertical orientation) are critical. Best placement of a Master for most universal coverage and greatest
range will be in an unobstructed, centrally placed locations. This is, of course, an ideal location and may
not be the most practical location to place the antenna. Mount the antenna such that it is vertically
orientated (either upright or upside down) since any angle other than vertical will result in weaker RF
transmission and receive strength relative to the slave(s). A pedestal mount style antenna is available
with a six-foot cable. For best performance place this antenna near the ceiling. Therefore, since the cable
length is six feet, the WNI (Wireless Network Interface) (Master) and antenna placement must be in close
proximity. The central PCMS monitor is connected to the WNI via a standard SMI ethernet cable.
In open areas such as long hallways, it may be better to place some of the WNI’s in rooms off the
hallway, allowing some intentional attenuation of the signal. This can actually improve performance where
several rooms are located on a long corridor because roaming monitors will be forced to switch more
often to a closer WNI. Remember that a wireless monitor does not switch to a new master just because
its signal is stronger, so if all of the WNI’s are in the open hallway a monitor may stay synchronized to a
distant WNI even though it may be right next to a WNI that would provide much better signal quality.
Sources of interference: Watch out for sources of RF interference such as microwave ovens and do not
place a WNI antenna closer than 20 feet from such sources. Remember to test all microwave ovens for
emissions! Remember to check the floors above and below the wireless location also, as an interference
source may easily penetrate a floor or ceiling.
WNI Channel Numbers - a setup tip: When low signal strength forces a wireless monitor to switch to
another WNI, it tries to synchronize with the available WNI’s from its list of known Masters. It may improve
performance slightly if the next number on the list happens to be the actual next WNI in the hallway. If
the WNI channel numbers are set so that, as a wireless monitor moves up the hallway, it encounters
numerically sequential channel numbers, it will tend make better Master selections. For example, if the
WNI channel numbers are set so that the monitor will encounter #2, then #3, then #4, etc. the monitor is
more likely to synchronize with the closest WNI. If the WNI channel numbers are set so that you pass #2,
then #9, then #6, etc, the monitor may synchronize with a more distant WNI (with less signal quality)
simply because it is the first WNI found that has acceptable
signal quality.
Bedside or Slave location
The placement of the slaves follows similar rules as the placement of a master. An open unobstructed
area is best for universal coverage and greatest range. Remember that other RF transmissions or
physical objects may interrupt the slave signals and waveform causing “drop outs”. Slaves can be in a
fixed location or they may be mobile within range of the master.
Overlapping Restrictions
Central or Masters
One master’s signal must never directly overlap another master on the same channel. Electronic devices
will not be damaged, but communications between some masters and slaves will be unpredictable
resulting in increased waveform dropouts. If there are two or more masters on the same channel, they
must be sufficient distance apart that the RF signal from one master will not directly overlap another.
Masters on the same channel, correctly separated, may be networked together by using Multiport
repeaters and standard SMI ethernet cables allowing areas blocked off by solid objects to be covered by
another master on the same channel. Multiple masters that are within RF signal coverage of each other
will not cause problems if masters are on separate, thumb wheel selected, channels.
Part Number 062-0983-01 Rev C page 3 - 14