Bird Technologies VPM3 - Manual (Page 26)

18
Mode
Note:
The Mode menu is only displayed if the sensor supports more
than one measurement mode. For the 7022 sensor the following is dis-
played.
Statistical
Switch to Statistical mode. See “Statistical Power Mode” on page 37
Note: The mode tab will update to reflect this.
Time Domain
Switch to Time Domain mode. See “Time Domain Mode” on page 33.
Note:
The mode tab will update to reflect this.
Average Power
Switch to Average Power mode. See “Average Power Mode” on page 11.
Note:
The mode tab will update to reflect this.
Configure
Note: This menu will change depending on the sensor being displayed.
Input Offset
To read the true power when using a coupler or attenuator, enter (in dB) the
attenuation or coupling factor. To convert percentages to dB, use the equation:
Attenuation dB
 
10 Log10 Attenuation percent
  100    
=
Note:
The Bird 5015-EF uses frequency-dependent correction factors
to provide more accurate measurements that are entered here. For
more information, refer to the owners manual for the 5015-EF.
Match Offset
The masking effect of cable loss can cause significant error when measuring
antenna VSWR or return loss levels. This masking can make an antenna to
“appear” to perform more efficiently than is actually the case. The offset error
may be corrected with the following equation:
RL at Antenna = RL at Transmitter - (2 x CL)
RL = Return Loss
CL = Cable Loss or Match Offset.
In the Match Offset dialog, enter the total insertion loss of the cable connected
between the power sensor and antenna, in dB. The VPM3 will correct the dis-
played match values according this equation.