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1.A.
System Overview
The KHF 1050 HF voice and data communication system is a solid state design
with 200 watts (PEP) of output power, operating at 28 Vdc. Frequency of operation
ranges between 2.0 and 29.9999 MHz with 100 Hz resolution. Systems may be
strapped to set the upper frequency limit to 22.9999 MHz.
The RM-855 RMU, the MC-850 MCDU, or the PS440 CDU allows the pilot to select
the frequency and mode of operation of the system and displays that information
to the pilot.
Receiver and low level transmitter signals are located in the KRX 1053
Receiver/Exciter. The KRX 1053 Receiver/Exciter employs a master oscillator,
which requires a short warm-up period when operating at cool temperatures.
The KAC 1052 Power Amplifier amplifies the excitation signal from the KRX 1053
Receiver/Exciter to 200 watts PEP, or 50 watts of carrier power in AM. The
amplified signal is routed to the KAC 1052 Antenna Coupler, which matches the
various impedances of the antenna to the 50 ohm output of the transmitter. In
receive function, signals from the antenna pass through the KAC 1052 Antenna
Coupler to the KRX 1053 Receiver/Exciter via the KPA 1052.
The KHF 1050 can be installed as a single or dual HF system. A configuration is
called a "dual system" when two KHF 1050 HF systems are installed in the same
aircraft to share one antenna. Both systems may receive simultaneously, but only
one system is chosen to transmit at any one time. An auto select transmit scheme
determines which system is selected to transmit. The characteristics of a dual KHF
1050 configuration are as follows:
•
When one system is transmitting, reception on the other system is disabled.
•
The first system (System 1 or System 2) to be keyed is selected to transmit, and
transmission from the other system is inhibited until the first system has
stopped transmitting.
•
The KHF 1050 does not require any external accessories for dual system
operation other than a specially fabricated coaxial cable to allow
interconnecting the two KAC 1052 Antenna Couplers to the antenna.
•
A primary advantage of a dual HF system is to provide HF-com redundancy. In
the event the pilot suspects improper operation of a dual KHF 1050 system, the
most robust performance is generally achieved by turning off one of the HF
systems. This will cause the remaining system to default to a single-system
status and potentially provide improved performance.
Revison 2
N
KHF 1050 SYSTEM INSTALLATION MANUAL
23-10-09
Page 4
Apr/2006
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