2.0 Identifying Faulty Cables and Antenna System Components
The Anritsu Cell Master and Site Master FlexCal™ broadband calibration feature is an OSL-based calibration method. It
offers field technicians a simple and convenient way to troubleshoot and identify faulty antenna system components
because it eliminates the need for multiple instrument calibrations and calibration setups. Field technicians can now
perform a broadband calibration and change the
frequency range after calibration without having to
recalibrate the instrument. A zoom in/zoom out
capability is available in Return Loss, Cable Loss or
VSWR mode. Because the resolution and maximum
distance are dependent on the frequency range, field
technicians - in DTF mode - can even change the
frequency range to produce the desired fault resolution
and horizontal range needed for the measurement
without performing additional calibrations.
The Site Master has a measurement range of 25 to
4000 MHz. When FlexCal is selected, Site Master is
calibrated from 25 to 4000 MHz. FlexCal has the same
accuracy as the OSL calibration method for this
frequency range. For frequency ranges other than 25 to
4000 MHz, measurement uncertainty may degrade
slightly due to calibration data interpolation. Therefore,
it is recommended that you perform another OSL
calibration to obtain the maximum possible measurement
accuracy when the data is to be used for archiving and
During network deployment, maintenance, and trouble shooting phases, insertion loss can be measured by disconnecting the antenna and connecting an enclosed short at the end of the transmission line. If a Tower Mounted Amplifier (TMA) is used in the transmission feed line system, it is best to remove the TMA and antenna from the system configuration to perform an insertion loss measurement. It is best to always disconnect the cable at the same location so the measured data can be compared to the historical data for accuracy and repeatability.
Using Site Master, cable insertion loss can be measured in CABLE LOSS or RETURN LOSS mode. In Cable Loss mode, Site Master automatically considers the signal traveling in both directions thus making the measurement easier for the user in the field.
The following section explains the procedure to measure insertion loss in cable loss mode and return loss mode. The measurement setup and equipment required is the same for both modes.
Measuring Insertion Loss Using CABLE
- Site Master Model S11xx, S33xx, or S251x
- Precision Open/Short, Anritsu 22N50 or Precision Open/Short/Load, Anritsu OSLN50LF
- Precision Load, Anritsu SM/PL
- Test Port Extension Cable, Anritsu 15NNF50-1.5C
- Optional 510-90 Adapter, DC to 7.5 GHz, 50 Ω, 7/16(f)-N(m)
Insertion Loss Measurement Setup
The insertion loss measurement set up for a typical transmission feed line system is shown in Figure 2. Remove the antenna and connect an enclosed precision "short" at the end of the transmission line.
If a Tower Mounted Amplifier (TMA) is in the transmission feed line system, remove the TMA and antenna and connect an enclosed short at the end of the transmission line. Insertion loss measurement for a transmission feed line system with a tower mounted amplifier is shown in Figure 3.