122  N9912A FieldFox User’s Guide  
Please observe the damage level of your U2000 Series Power Sensor. 
Typical damage levels of the U2000 Series Power Sensor are: 
+25 dBm (320 mW) average 
+33 dBm peak (2 W) <10μs 
+5V 
How to Connect the Power Sensor 
Connect your U2000 Series Power Sensor to one of the USB ports. 
NOTE  Use an attenuator between the DUT and the power sensor when measuring 
power levels that are higher than +20 dBm. The attenuator value can be 
subtracted from the measurement using the Offset feature, discussed on page 
124. 
A sequence of status lights are displayed on the base of the power sensor.  
  Green blinking light indicates the power sensor is communicating or self-tests 
are being performed. Because the FieldFox is usually communicating with the 
power sensor when it is connected, this is the normal mode of operation. 
  Amber light indicates Internal Zeroing is being performed. 
  Red light indicates an error has occurred with the power sensor. Refer to 
power sensor documentation. 
  No light indicates the FieldFox is not communicating with the power sensor. 
This is the case when NOT in Power Meter Mode.  
Power Meter Settings 
Select Power Meter Mode before making any setting in this section. 
How to select Power Meter Mode 
  Press  Mode_.  
  Then Power Meter (USB Sensor). 
Zeroing 
The Agilent USB Power Sensors perform Internal Zeroing automatically. Because 
the U2000 series power sensors have an internal switch, Internal Zeroing does 
NOT require that the power source be turned OFF.  
For highest measurement accuracy, when measuring power levels below –30 
dBm, External Zeroing should be performed.  
During External Zeroing, the power source MUST be turned OFF or the power 
sensor disconnected from the power source (device under test).  Power is OFF 
when power sensor measurements are below –60 dBm. When power higher than 
this is detected at the sensor, a warning message is shown on the FieldFox and 
External Zeroing will not proceed. 
How to perform External Zeroing 
  Press Cal 5 . 
  Then External Zero.