SanDisk 5000 2.5" User Manual

Page 13

Advertising
background image


360 Herndon Parkway

Suite

1400

Herndon, VA 20170

http://www.rheintech.com

SanDisk Corporation

Page 13 of 17

DoC Report
2006137
04/27/07

5.2 FIELD

STRENGTH

CALCULATION

The field strength is calculated by adding the Antenna Factor and Cable Factor, and subtracting the
Amplifier Gain (if any) from the measured reading. The basic equation with a sample calculation is as
follows:

FI(dBuV/m) = SAR(dBuV) + SCF(dB/m)

FI = Field Intensity

SAR = Spectrum Analyzer Reading

SCF = Site Correction Factor

The Site Correction Factor (SCF) used in the above equation is determined empirically, and is
expressed in the following equation:

SCF(dB/m) = - PG(dB) + AF(dB/m) + CL(dB)

SCF = Site Correction Factor

PG = Pre-amplifier Gain

AF = Antenna Factor

CL = Cable Loss

The field intensity in microvolts per meter can then be determined according to the following equation:

FI(uV/m) = 10

FI(dBuV/m)/20


For example, assume a signal at a frequency of 125 MHz has a received level measured as 49.3
dBuV. The total Site Correction Factor (antenna factor plus cable loss minus preamplifier gain) for
125 MHz is -11.5 dB/m. The actual radiated field strength is calculated as follows:

49.3 dBuV - 11.5 dB/m = 37.8 dBuV/m

10

37.8/20

= 10

1.89

= 77.6 uV/m


Advertising