Chapter 4 Capturing and Analyzing Data
The following sections describe the various ComProbe software functions that capture and display data
packets.
4.1 Capture Data
4.1.1 Air Sniffing: Positioning Devices
When capturing over the air packets, proper positioning of the Frontline hardware and the Devices Under
Test (DUTs) will result in the best possible captures and will mitigate sources of path loss and interference.
The following procedures will help optimize the capture process especially if you are have problems
obtaining reliable …captures.
Problems with indoor radio propagation
Even in free space, it is well understood that radio frequencies attenuate over distance. The free-space rule-
of-thumb dictates that radio energy decreases in strength by 20 dB by each 10-to-1 increase in range. In the
real-world, the effects of objects in an outdoor environment cause reflection, diffraction, and scattering
resulting in greater signal losses. Indoors the situation can be worse. Reflections occur from walls and other
large flat surfaces. Diffraction occurs from objects with sharp edges. Scattering is produced from objects with
rough surfaces and from small objects. Also any object directly in the path of the radiation can present a hard
or soft partition depending on the partition's material properties. Path losses from partitions are difficult to
estimate.
Estimating indoor propagation loss
One estimate of indoor path loss, based on path loss data from a typical building, provides a
power
rule. At 2.4 GHz, the following relationship provides an approximate estimate of indoor path loss:
This approximation is expected to have a variance of 13 dB.
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Summary of Contents for BPA LOW ENERGY
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