Chapter 9 Reflection Operation
Changing the units settings
150 9102 Handheld Spectrum Analyzer Software version 5.31
The measurement graph shows full reflection (0 dB return loss) as soon
as the calibration set is removed. The instrument is now ready for
starting the reflection measurement.
Changing the units settings
The reflection mode supports all common reflection measurement
units:
– Return loss
The most common reflection measurement unit. Using this unit the
attenuation of the reflected signal against the test signal power is
measured. Due to the fact that the return loss is linked to the signal
power this measurement unit is very easy to handle. A return loss
of 20 dB for example, means that
1/100 of the transmitted power is reflected back to the radio.
Usually a return loss of around 17 dB is required to accept an
antenna as functional.
–VSWR
This unit is based on the RF signal voltage. It represents a ratio of
transmitted and received voltage. Using special alignment charts all
units can be easily compared to each other. A return loss of 20 dB
for example is equivalent to a VSWR of 1.22.
– Reflection factor
This unit is also based on the RF signal voltage and shows the
reflection in mRho.
– Reflection power
This unit shows the reflected power ratio as a percentage.
In order to select the measurement unit for your reflection measure-
ment proceed as follows:
1 In the Reflection main menu select
Level > Units. The Unit menu is
displayed on the right-hand side of the screen.
2 Select Return Loss, VSWR, Refl. Factor or Refl. Power by pressing
the respective softkey followed by E
NTER. The selected unit will be
displayed on the left-hand side of the results display.
NOTE
When performing a number of measurements it can be necessary to
repeat the calibration process due to temperature changes etc. This
is regular behaviour. Furthermore if you change the frequency band,
calibration has to be repeated. As soon as calibration is necessary
the 9102 will inform you by displaying the red “Calibrate“ icon.
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