Bird Technologies SH-362S-Manual - Manual (Page 140)

118
Units
Soft key functions that select the units of measure (Figure 100) are enabled.
For power measurements, Watts or dBm can be selected.
For match measurements, VSWR, dB, rho, and percent (%) can be selected.
Figure 100 Power Meter, Digital Display, Units Screen
(Directional sensor)
Note: The Units screen applies to Directional and
Wideband Power sensors only.
Power: Watts
Measures power in Watts.
Power: dBm
Measures power in dBm.
Match: VSWR
Measures match, a complex ratio of reflected power to forward power
expressed in VSWR.
Note: “Pr” = Reflected Power, “Pf” = Forward Power
Match: Return Loss dB
Measures match, a complex ratio of reflected average power to forward power
expressed in dB.
Power Watts
 
10 dBm 30 –
  10   
=
Power dBm
 
10 Log Power Watts
    
= 30dB +
VSWR 1 Sqrt Pr Pf
  
+
  1 Sqrt Pr Pf   
–
  
=
ReturnLoss dB
 
10 Log Pr Pf
   
=