Model RF Obstacles 125

Model RF Obstacles When planning a 3Com network, you need to consider how the building layout and physical objects affect signal loss. Walls, windows, and doors absorb RF signals, and different building materials have different attenuation factors.

You can model an RF obstacle on your floor plan and assign the obstacle type and attenuation factor, or you can assign an obstacle type and attenuation factor to objects in a DWG or DXF drawing. 3WXM uses these values when calculating coverage for the network.

If you do not have an imported drawing, or if you are working with a GIF or JPEG image, you must create RF obstacles manually. If you are using an imported CAD drawing, you can convert many of the objects in the drawing into RF obstacles. All objects similar in construction material should be placed in one layer. For example, if the drawing file has walls spread out in different layers, but after performing a site-survey, they walls were found to be similar in material construction, it is better to put them in one layer. In this way, the RF attenuation assignment can be performed in one step.

This section show how to select and draw objects and convert them into

RF obstacles. 3WXM preserves the layers defined in a CAD drawing.

Table 13 provides some common AutoCAD layer terminology.

Table 13 Common AutoCAD Layer Terminology

AutoCAD Layer Name

Commonly Represents...

glaz

windows

 

 

scol

steel columns

 

 

p-fixt

bathroom

 

 

p-part

bathroom stall partitions

 

 

ext

exterior

int

interior