Different Uses - Chauvin Arnoux ORITEL IR 205 Manual De Instrucciones

3.2

Different uses

The SWR indicator is the measuring instrument which must be associated with a microwave educational
bench detector:
- associated with an ORITEL LAF 100 measuring line, it enables a standing wave ratio to be measured.
- associated with a detector, it enables an attenuation or insertion loss to be measured.
- associated with the antenna educational bench detector, it enables the radiation pattern of an antenna
as well as its gain to be determined.
To carry out one of the measurements described above, follow the procedure set out below:
Energization
Connect the instrument to the power supply network (see § 3.1).
- Energize the instrument by pressing the mains push button
Preliminary adjustments
- Set the main attenuator
- Set the "Coarse" and "Fine" gain controls
Connection
- Link the detected output (female BNC connector) of the detection device used (measuring line or
detector) to the female BNC input connector on the SWR indicator using a coaxial " male-male BNC
" lead.
Frequency tuning
- With the control , adjust the tuning frequency of the instrument to obtain the maximum on the
galvanometer
- If the galvanometer indication is too low, increase the instrument's sensitivity by reducing the value
on the main attenuator
sensitivity of the instrument by increasing the value on the attenuator.
- Possibly retune the frequency using the control
with the main attenuator
Obtaining a reference (reset/calibration)
- Move the galvanometer pointer to the 0 dB mark of the dB scales or to 1 in the SWR scale while
increasing the gain of the amplifier using the "Coarse" and "Fine" gain controls
indicated below for each of the types of measurement.
SWR measuring
This measurement is performed using an ORITEL LAF 100 measuring line, linking its detected output
to the "Input" connector of the SWR indicator.
- Calibration is carried out by placing the pointer of the reading galvanometer on the SWR = 1 marker
when the electric field detected is maximum (electric field antinode); this position can be achieved
by moving the measuring line carriage.
- The SWR is measured by moving the measuring line carriage until a minimal value is obtained on
the instrument's galvanometer; the reading then corresponds to the SWR measured.
Measuring attenuation
This is measured by linking the "Input" connector of the SWR indicator to the detected output of an
ORITEL DEN 100 detector.
- Calibration is performed by moving the galvanometer pointer onto the 0 dB marker for a maximum
detected electric field value
- attenuation, insertion loss or level deviation can be measured by directly reading on the scales
graduated in dB, when the electric field detected is different from the value previously used for
calibration.
Note : Since the different measurement scales are graduated for square-law demodulators, it is important
to make sure that the electric fields measured are sufficiently weak for the detector used to be within a
square-law detection area.
to 30 dB, which corresponds to medium sensitivity.
to the half-way point in their rotational travel.
, and, reciprocally, if the galvanometer indication is too high, reduce the
, and if necessary choose a new sensitivity range
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in the conditions