User Manual Part 1

FSG 90F System
2. General Description
Page 10 November 2000
W. Dittel GmbH
2.4 Brief Description
Both radios out of the FSG 90F System are miniaturized, lightweight, panel-mounted
1.8" high flat-pack VHF/AM transceivers operating in the airband frequency range
118.000 MHz ... 136.975 MHz, thus providing either 2,278 channels with 8.33 kHz/
25 kHz channel spacing, or 760 channels only with 25 kHz channel spacing, covering a
standard communications distance of 100 NM (nautical miles) at FL 70.
Case dimensions of all models will fit into a standard ARINC NORM rectangular opening
of the instrument panel or console, fixing is done by 4 DZUS fasteners. Depth including
wiring is 215 mm.
All control and display elements are located on the front panel. Connections to the
electrical environment are made through a 25-pole SUB-D connector and a BNC female
connector at the rear panel of the units.
The ICAO channel name (8.33 kHz/25 kHz spacing) and / or operating frequency
(25 kHz spacing), supply indicator, transmit indicator, channel memory number and
SET-UP information are all indicated at a two-line Liquid Crystal Display (LCD, can be
back-lit).
Three display modes are user selectable:
• Use/STBY Mode: Active channel name or frequency, selectable standby channel
name / frequency
• Channel Mode: Active channel name or frequency, associated preset channel
memory number (1 … 99)
• Direct Tune Mode: Active channel name or frequency only.
With the Dual Mode models FSG 90F and FSG 90F-H1, up to 99 channel memories in
8.33 kHz / 25 kHz CH spacing (6-digit display), and another set of up to 99 channels in
the '25 kHz only' CH spacing (5-digit display) can be preset. After change to the other
operating mode (from 8.33/25 kHz to 25 kHz only, or from 25 kHz only to 8.33/25 kHz),
each stored set of up to 99 channel memories remains available.
Preset channel memories remain available also after manual or automatic power-off.
The non-volatile channel memories of the FSG 90F(X) can easily reprogrammed also
during flight or ground operation.
Programming can be done in the actual (8.33/25 kHz or 25 kHz only) mode.
Deleting channel memories is only possible during SET-UP.
For ground applications, limitation to use preset channel(s) only can be determined in
(password protected) SET-UP.
Channel name / frequency, or preset channel memories are selected with the dual
function F/CH switch.
Both Transmit and Receive use the same digital frequency synthesizer and one
temperature calibrated reference crystal (accuracy 1 ppm).
The dual Superhet receiver offers very high immunity against in-band and out-of-band
interference and intermodulation (Annex 10 FM immunity).
The automatic AM/FM Squelch (threshold adjustable in 4 levels, SET-UP) and the
normally active transmitter blocking during Receive are disabled by pushing the SQ
button, and enabled when the SQ button is pushed again.
An audio low pass filter for areas using Climax operation in 25 kHz spacing is
incorporated.
Separate Audio amplifiers power the speaker (4 Watts / 4 Ohms or 8 Watts / 2 Ohms),
and the headphones (100 mW / 600 Ohms).
The solid state transmitter is wideband tuned from 118 to 137 MHz and delivers at least
an RF carrier power of 6 Watts or 10 Watts for the FSG 90F-H1 model.