ETS-Lindgren 3160 Pyramidal Standard Gain Antenna User Manual
Page 44
44
Radiated Emissions Measurements
www.ets-lindgren.com
The losses of the coaxial cable, A
c
, should be included in the
computations. In this case, the previous equation becomes:
RF Voltage, dB(µV) + Cable Loss, dB +
Antenna Factor, DB(m
-1
) = Field Strength, dB(µV/m)
E
a
= V
a
+ A
c
+ AF
Conversion Formulas
Following are some useful conversion formulas, including how the constants are
obtained:
E
QUATION
1
dBm=dB(
V)-107
The power is related to the voltage and the system impedance as:
P
V
R
2
In a 50 Ω system, the previous equation becomes:
10
20
10
50
10
10
10
log
log
log ( )
P
V
Converting from dB to dBm for power and from dB(V) to dB(
µ
V) for
voltage, the overall constant becomes:
30 120 10
50
107
10
log ( )