Agilent Technologies FieldFox N9912A - Check for Compressed Measurements; Field Strength Measurements

SA (Spectrum Analyzer) Mode 77
How to control the Preamp
By default, the preamp is OFF.
 Press Scale/Amptd.
 Then Preamp ON OFF The underlined setting is the current setting. When ON,
PA is shown to the left of the graticules on the display.
Check for Compressed Measurements
Compression occurs when too much power into an amplifier causes it to no
longer amplify in a linear manner. When too much power goes into the FieldFox
RF IN connector, the amplifiers in the SA receiver compress and signal power
will not be displayed accurately. This can occur even if ADC Over Range is not
displayed. Increase the RF Attenuation value to prevent the SA receiver from
being compressed.
How to Check for a Compressed Measurement
 Using a marker at the signal peak, make note of the signal power level.
 Increase the RF Attenuation level by 5 dB.
o If the signal level does NOT change, then NO compression exists. This
indicates that the signal is in the linear region of the FieldFox receiver.
o If the signal level DOES increase, then the receiver was compressed. Set the
RF Attenuation value at the setting when further increases no longer result
in an increase in the displayed power level.
Field Strength Measurements
To measure the strength of any signal transmitted through the air, an antenna
must be connected to the FieldFox. The Field Strength feature allows you to
enter the frequency response of the receiving antenna (the Antenna Factor) and
associated cabling, and then have amplitude corrections automatically
compensate the displayed trace for that response.