Bird Technologies 5019D-Manual - Manual (Page 20)

8
VSWR
VSWR measures the relation between forward and reflected
average power. The Bird Wideband Power Sensor calculates
the VSWR from the Forward and Reflected Average Power
measurements. Rho and Return Loss are also the same mea-
surement, but in different units:
Rho
Rho
  
P
R
P
F

=
VSWR
VSWR
1

+
1

–
------------ =
Return Loss (dB)
ReturnLoss dB
 
10 P
R
P
F
  
log =
The health of the feedline and antenna systems can be moni-
tored using VSWR measurement under full power operating
conditions. High VSWR is an indicator of feed line damage,
overtightened cable or feed line clamps, or antenna changes/
damage due to weather conditions, icing, or structural dam-
age to the tower.