Siemens Simatic RF600 System Manual page 60

RF600 system planning
4.3 Antenna configurations
Calculation of the radiated power with consideration of the cable loss a
If the transmitted power is not applied directly but via a cable with loss a
compensated such that the same radiated power is obtained.
If the loss is not appropriately compensated, the radiated power is too small.
General preliminary information on the unit "dB"
Requirements
This section provides you with information on the unit "decibel". This knowledge is a
requirement for optimum understanding of the following section. You can ignore this section
if you already have the appropriate knowledge.
Definition
When specifying decibels, the ratios between powers or voltages are not defined directly but
as logarithms. The decibel is therefore not a true unit but rather the information that the
specified numerical value is the decimal logarithm of a ratio of two power or energy variables
P1 and P2 of the same type.
This ratio is defined by the following equation:
Example
If P1 = 200 W and P2 = 100 mW, how large is the ratio a in dB?
60
k
System Manual, xx/2014, J31069-D0171-U001-A15-7618
, this loss should be
K
SIMATIC RF600