SkyTrac Systems Ltd.
Document Rev. 02.010
ISAT-100-OPD-SOI
Page 19 of 26
Restricted Proprietary and Confidential Information
4.7.5 MIC LEVEL Adjustment
The microphone input amplifier has a high gain to accommodate a wide range of input
voltages; however inputting a strong signal at high gain (high MIC LEVEL setting) will
exceed the input range of the satellite modem. If the input signal exceeds the modem input
range, the signal will be clipped to prevent damage.
The microphone input requires an input of 0.050 Vrms at max MIC LEVEL setting for full
output.
Maximum input without clipping at minimum MIC LEVEL setting and no audio signal clipping
is 1.4 Vrms.
The microphone volume can be adjusted via the MIC LEVEL potentiometer accessible via
the top of the ISAT.
To select the appropriate MIC LEVEL and avoid clipping the microphone signal, follow the
procedure below:
1. Adjust ISAT-100 to minimum MIC LEVEL.
2. Establish a phone call.
3. Slowly increase the MIC LEVEL until desired volume is heard on receiving end.
If audio signal quality begins to degrade while increasing gain, decrease gain until
signal quality is good.
4.8 Post Installation Tests
4.8.1 Initial Verification Test
The avionics installer must perform this test immediately after installation and system
activation via SkyWeb Hardware Manager.
a) Move aircraft to a location with unrestricted visibility of the sky.
b) Turn on aircraft master/avionics switch. Power and Charge LED should light up
immediately followed by the BAT, MDM and GPS LED. The MDM or GPS LED
will blink steadily when trying to obtain a lock and will remain on solid once a
lock has been obtained. This could take up to 2 minutes depending on how
many satellites are in clear view. Note that it is normal for the GPS and MDM
LEDs to blink occasionally as satellites move in and out of range. If the ISAT is
locked to less than 4 GPS satellites once a GPS lock has been obtained, the
GPS LED will blink in a repeating pattern of: two quick blinks, on solid.
Optional: If the audio system is connected a tone should be heard when the
ISAT starts up.
The document reference is online, please check the correspondence between the online documentation and the printed version.
