User's Manual

BreadCrumb
®
LX User Guide Rajant Corporation
June 25, 2008 Version 1.06
- 19 -
4.3 CHANNEL ASSIGNMENTS
By default, BreadCrumb LX devices use channels 152 and 11 upon startup.
In some cases, however, it is
necessary to manually set the radios to different channels as described below.
4.4 PHYSICAL PLACEMENT AND OTHER CONSIDERATIONS
Commonly occurring environmental factors have a significant impact on performance and behavior of the
BreadCrumb Wireless Network. LOS (Line of Sight) obstructions, distance, weather, and device placement
should all be considered when deploying a wireless network.
IEEE 802.11a/b/g wireless operation degrades gracefully as distance increases between nodes or as interference
becomes prominent. This manifests as a data rate reduction between nodes.
The goal in planning and deploying a BreadCrumb Wireless Network is to maximize both coverage and the data
transfer rate between devices. These can be maximized by taking into consideration all of the contributing factors
described in this section.
4.4.1 LINE OF SIGHT
Unobstructed LOS (Line of Sight) is critical for optimal performance of the BCWN. Partial LOS obstruction
results in noticeable network performance degradation. Total LOS obstruction can result in complete loss of
network connectivity.
Elevating the device and external antenna will assist in providing better LOS. This can allow the radio waves to
propagate over some possible obstructions.
Unobstructed LOS is not necessary from every BreadCrumb and wireless client to every other BreadCrumb and
wireless client. However, each device must have unobstructed LOS to the previous and subsequent device.
Client connectivity will degrade, and if significantly dense, drop if LOS to a BreadCrumb can not be maintained.
4.4.2 DISTANCE
• There are many factors to determine acceptable distances to place BreadCrumbs when deploying a
wireless network.
• If many devices are placed too closely together, it is possible that interference will degrade the
performance of the system.
• Devices placed too far away or in RF ‘shadows’ may experience total loss of connection.
• Device power is important in determining distances that the device will be effective.
• When placing a BreadCrumb, check the connection status to the most available device with BCAdmin. If
the connection is poor or non-existent, attempt to relocate the BreadCrumb closer to the available device
until acceptable connection is achieved. If poor or no connection is made at even relatively close
distances, you should refer to the troubleshooting section of this guide.
• When the connection quality is found to be acceptable from BCAdmin, the distance of the BreadCrumb
from the network can be increased until an optimal balance between distance, connectivity and tactical
placement is achieved.
• BCAdmin is an administrative software application that can aid in deploying a BreadCrumb wireless
network. Refer to section 3.0 of this manual regarding BCAdmin.