DANPHONE Futronic GMDSS-AIS-SART, User Manual, Page: 28 / 42

28
FM Deviation
The illustration shows how to measure the VHF FM Deviation on CH 6:
The test procedure is as follows:
- In the FM DEVIATION mode, select the sub mode MEAS,
- Take the 1 kHz AF generator supplied with the test box close to the transmitter’s microphone
and activate the tone,
- Start TX on the transmitter on CH6,
- Press OK on the test box. Maximum deviation (FM DEVI) and actual deviation (ACT DEVI)
are shown on the LCD display,
- Press OK on the test box, and the maximum deviation value will be stored in the memory,
- Stop TX on the transmitter.
If the message NOT CALIBRATED is displayed, the test box needs calibration. See page 36.
Example of Printout from the Memory:
CONTROL MEASUREMENT ON MMSI NO: 3538410000 - HOUR:14 DATE:09-09-2006
FM DEVIATION: 4.5KHZ
AM / 123.1 MHz
Using the same set-up as with measuring the FM deviation, it is also possible to measure the
frequency and modulation of an AM signal transmitted on 123.1 MHz.
At frequency measurements, take care not to modulate the transmitter, and when checking the
modulation (AF) be aware that a strong input signal will be limited in the test box and thus
reduce the amplitude of the AF signal coming from the internal loudspeaker.
The first sub mode choice is between IMG and ORD. Same measured frequency in both sub
modes indicates that it is not a mirror frequency.
The next sub mode choice is between FRQ (frequency measurements) and AF (audio mode).
At FRQ, the frequency is measured when the transmitter is activated. FRQ and LEVEL are
shown on the LCD display and are also stored in MEMORY.
At AF, the internal loudspeaker is activated and the AM modulated signal can be heard.
Pressing any of the buttons will terminate the test.
ANT.
VHF TRANSMITTER
1 KHZ AF
GENERATOR