Marconi 915 User Guide

HF AIRBORNE TRANSCEIVER

Extensive research and development
activities by Marconi Selenia
Communications in the HF field have
led to the design and production of
advanced HF/SSB system for fixed­wing aircraft and helicopters.

These transceivers provide
voice/data radiocommunications for
airborne applications over the 2 to
30 MHz frequency range.

Designed to meet the most
diverse requirements,they
provide various output power
possibilities (from 100 W to 400
W) and a wide range of
voice/data services in the
USB/LSB/AM and CW modes.

Data communication
capabilities include Link-11,
as per STANAG 5511.

The components of this HF systems
family has been specifically designed
for airborne applications,where a
very tough EMI environment is
expected,such as in co-located
installations requiring simultaneous
operation of several radios (i.e.
voice/data) on the same airborne
platform.

Storage of operation-related data
reduce the operator workload
during the mission phase.

Maintenance is simplified by
advanced BITE facilities
allowing failure isolation down to
module level.

Extensive flight tests on helicopters
and fixed-wing aircraft have
demonstrated excellent
performance in the most severe
environments.

All the systems ar powered by
115Vac / 400 Hz 3-phase power
line, but there is also a DC
powered version of the SRT-[170,
270]/L version,i.e. the SRT-170/M
system,which is suitable for
installation in very severe EMI
environments.

The SRT-170/M combines high
flexibility and simplified operation
in a reduced size and weight
package, achieved through
innovative electrical and
mechanical design.

The receiver/exciter and RF
amplifier are assembled into a
single, 1/2 ATR sized LRU.

All these HF systems are currently
in service on several airborne
platforms.

Any of these transceivers can be
interfaced with various Antenna
Tuning Units (ATU) dedicated to
Loop,Wire or Notch antennas.

As an example, a typical
configuration for helicopter
installation includes an externally
mounted ATU (ATU-1992, an
aerodynamically shaped unit,suited
for external installation on the
fuselage of low-speed aircraft),
and a Loop antenna.

The external ATU installation
reduces the problems
of EMI with other equipment
onboard.

The Loop antenna allows use of HF
ionospheric propagation in the
‘Near Ver tical Incidence Skywave’
(NVIS) mode.

The combination of NVIS and
surface-wave modes provides
reliable radio communication over
adverse terrain.

DESCRIPTION

HF AIRBORNE TRANSCEIVERS