BendixKing KHF 990 User Manual
KHF 950/990
HF Communications Transceiver
PILOT’S GUIDE
AND DIRECTORY OF HF SERVICES
A
Table of Contents
INTRODUCTION
KHF 950/990 COMMUNICATIONS TRANSCEIVER . . . . . .I
SECTION I
CHARACTERISTICS OF HF SSB WITH ALE . . . . . . . .1-1
ACRONYMS AND DEFINITIONS . . . . . . . . . . . . . . .1-1
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
HF SSB COMMUNICATIONS . . . . . . . . . . . . . . . . . .1-1
FREQUENCY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-2
SKYWAVE PROPAGATION . . . . . . . . . . . . . . . . . . . .1-3
WHY SINGLE SIDEBAND IS IMPORTANT . . . . . . .1-9
AMPLITUDE MODULATION (AM) . . . . . . . . . . . . . . .1-9
SINGLE SIDEBAND OPERATION . . . . . . . . . . . . .1-10
SINGLE SIDEBAND (SSB) . . . . . . . . . . . . . . . . . . .1-10
SUPPRESSED CARRIER VS.
REDUCED CARRIER . . . . . . . . . . . . . . . . . . . . . . .1-10
SIMPLEX & SEMI-DUPLEX OPERATION . . . . . . . .1-11
AUTOMATIC LINK ESTABLISHMENT (ALE) . . . . .1-11
FUNCTIONS OF HF RADIO AUTOMATION . . . . . .1-11
ALE ASSURES BEST COMM
LINK AUTOMATICALLY . . . . . . . . . . . . . . . . . . . . . .1-12
SECTION II
KHF 950/990 SYSTEM DESCRIPTION. . . . . . . . . . . . . .2-1
KCU 1051 CONTROL DISPLAY UNIT . . . . . . . . . . . .2-1
KFS 594 CONTROL DISPLAY UNIT . . . . . . . . . . . . .2-3
KCU 951 CONTROL DISPLAY UNIT . . . . . . . . . . . .2-5
KHF 950 REMOTE UNITS . . . . . . . . . . . . . . . . . . . . .2-6
KAC 952 POWER AMPLIFIER/ANT COUPLER .2-6
KTR 953 RECEIVER/EXITER . . . . . . . . . . . . . . .2-7
ADDITIONAL KHF 950 INSTALLATION OPTIONS .2-8
SINGLE KHF 950 SYSTEM CONFIGURATION .2-9
KHF 990 REMOTE UNITS . . . . . . . . . . . . . . . . . . . .2-10
KAC 992 PROBE/ANTENNA COUPLER . . . . .2-10
KTR 993 RECEIVER/EXITER . . . . . . . . . . . . . .2-11
SINGLE KHF 990 SYSTEM CONFIGURATION . . .2-12
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SECTION III
OPERATING THE KHF 950/990 . . . . . . . . . . . . . . . . . . . . . .3-1
KHF 950/990 GENERAL OPERATING INFORMATION . . . .3-1
PREFLIGHT INSPECTION . . . . . . . . . . . . . . . . . . . . . . .3-1
ANTENNA TUNING . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
FAULT INDICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2
TUNING FAULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3
KHF 950/990 CONTROLS-GENERAL . . . . . . . . . . . . . . .3-3
KCU 1051 CONTROL DISPLAY UNIT OPERATION . . . . . . .3-4
KCU 1051 GENERAL OPERATING INFORMATION . . .3-4
KCU 1051 CONTROL DESCRIPTION . . . . . . . . . . .3-4
PUSH ON/VOL . . . . . . . . . . . . . . . . . . . . . . . . . .3-4
SQUELCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4
CURSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-5
VAR/PUSH CHAR . . . . . . . . . . . . . . . . . . . . . . . .3-5
CLEAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
ENTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-6
MESSAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7
SCAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7
KCU 1051 DISPLAY AND CONTROL OPERATION 3-8
DISPLAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8
PAGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8
DATA STORE AND RECALL KEYS . . . . . . . . .3-10
CLR KEY . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10
ENT KEY . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10
MICROPHONE KEY OPERATION. . . . . . . . . .3-11
OPERATOR ALERTS . . . . . . . . . . . . . . . . . . . .3-11
COMMON DISPLAY FORMATS . . . . . . . . . . . .3-13
OPERATION / MODE FIELD . . . . . . . . . . . . . .3-14
STATE / SELECTION-CATEGORY FIELD . . . .3-14
RECEIVE./TRANSMIT STATE . . . . . . . . . . . . .3-14
MESSAGE/UNTUNED FLAG . . . . . . . . . . . . . .3-14
SECOND LINE OF DISPLAY . . . . . . . . . . . . . .3-14
LARGE DATA FIELDS . . . . . . . . . . . . . . . . . . .3-15
MANUAL MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-15
FREQUENCY AGILE . . . . . . . . . . . . . . . . . . . . . . . .3-16
ITU CHANNEL OPERATION . . . . . . . . . . . . . . . . . .3-16
CHANGES TO ALE AND ITU CHANNELS . . . . . . .3-16
INITIAL MANUAL CHANNEL . . . . . . . . . . . . . . . . . .3-17
MANUAL CHANNEL ENTRY . . . . . . . . . . . . . . . . . .3-17
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ALE MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-18
ALE IDLE STATES . . . . . . . . . . . . . . . . . . . . . . . . .3-18
ALE MODE DISPLAYS . . . . . . . . . . . . . . . . . . . . . .3-19
ALE IDLE SCANNING . . . . . . . . . . . . . . . . . . . . . . .3-20
ALE IDLE NOT SCANNING . . . . . . . . . . . . . . . . . . .3-20
ALE CALL IN PROGRESS . . . . . . . . . . . . . . . . . . .3-20
ALE LINKED TO ADDRESS . . . . . . . . . . . . . . . . . .3-21
ALE RECEIVING AMD MESSAGE . . . . . . . . . . . . .3-21
ALE SOUND RECEIVED FROM ADDRESS . . . . .3-22
ALE SOUNDING USING ADDRESS . . . . . . . . . . .3-22
SEND PAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-23
SEND PAGE DISPLAYS . . . . . . . . . . . . . . . . . . . . .3-23
SEND MESSAGE PAGE (TRANSMIT AMD MESSAGE) 3-23
SEND SOUND AS PAGE (BROADCAST A SOUND) . .3-24
SEND LQA PAGE (PERFORM AN LQA) . . . . . . . . . . . .3-24
SYSTEM TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-25
TEST REPORT PAGE . . . . . . . . . . . . . . . . . . . . . . . . . .3-25
SYSTEM REVNUM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26
SYSTEM LQA SCORE . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26
LQA SCORE PAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-26
SYSTEM PROGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27
PROGRAM MESSAGES . . . . . . . . . . . . . . . . . . . . . . . .3-29
EDIT TX (EDIT AMD TRANSMIT MESSAGES) . . .3-29
REV RX (REVIEW RECEIVED AMD MESSAGES) 3-30
DEL RX (DELETE AMD RECEIVED MESSAGE) .3-30
DEL RX (ALL SELECTED) . . . . . . . . . . . . . . . . . . .3-31
COPY RX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-31
PROGRAM OPERATION . . . . . . . . . . . . . . . . . . . . . . . .3-31
INTERVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-32
ACTIVITY LIMIT TIME-OUT PERIOD . . . . . . . .3-33
SCAN RATE . . . . . . . . . . . . . . . . . . . . . . . . . . .3-33
AUTOMATIC SOUNDING INTERVAL . . . . . . .3-33
CALLTIME . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-33
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ENABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-34
ENABLE AUTOMATIC SOUNDING . . . . . . . . .3-35
ENABLE LQA IN CALL . . . . . . . . . . . . . . . . . . .3-35
ENABLE RECEPTION OF AMD MESSAGES . .3-35
ENABLE RECEPTION OF ANYCALLS . . . . . . .3-35
ENABLE RECEPTION OF ALLCALLS . . . . . . . .3-35
ENABLE RECEPTION OF WILDCARD CALLS 3-35
ENABLE NUMERIC DIGIT ROLL OVER . . . . . .3-36
BRIGHTNESS SETTING . . . . . . . . . . . . . . . . . . . . .3-36
PROGRAM CHANNEL . . . . . . . . . . . . . . . . . . . . . . . . . .3-37
ALE CHANNEL DATA . . . . . . . . . . . . . . . . . . . . . . .3-37
CHANNEL GROUPS (CHGRP) . . . . . . . . . . . . . . . .3-38
SCAN-LIST (SCAN-LIST) . . . . . . . . . . . . . . . . . . . .3-39
TUNE ALL UNTUNED CHANNELS (TUNE-ALL) . .3-39
NEED TUNE COMPLETED . . . . . . . . . . . . . . .3-39
CLEAR TUNES FROM ALL TUNED CHANNELS .3-40
MARKING UNTUNED . . . . . . . . . . . . . . . . . . . .3-40
PROGRAM ADDRESS . . . . . . . . . . . . . . . . . . . . . . . . .3-41
ALE ADDRESS ENTRY PAGE . . . . . . . . . . . . . . . .3-41
SINGLE ADDRESS ENTRY . . . . . . . . . . . . . . . . . . .3-44
SELF ADDRESS . . . . . . . . . . . . . . . . . . . . . . . .3-44
RESPONSE TIME . . . . . . . . . . . . . . . . . . . . . . .3-45
SPECIAL ADDRESS TYPES . . . . . . . . . . . . . . . . . .3-45
MESSAGE PAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-46
KCU 1051 OPERATIONS SUMMARY . . . . . . . . . . . . . . . . .3-48
KCU 951 CONTROL DISPLAY UNIT OPERATION . . . . . . .3-50
KCU 951 CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . .3-50
OFF/VOLUME . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-50
SQUELCH/OPTIONAL SELCAL . . . . . . . . . . . . . . .3-51
CLARIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-52
MODE BUTTON . . . . . . . . . . . . . . . . . . . . . . . . . . .3-52
FREQ/CHAN BUTTON . . . . . . . . . . . . . . . . . . . . . .3-53
DIRECT TUNING A FREQUENCY . . . . . . . . . . . . .3-54
CHANNEL OPERATION AND PROGRAMMING 1 .3-55
CHANNEL OPERATION AND PROGRAMMING 2 .3-56
RECEIVE-ONLY CHANNEL PROGRAMMING . . . .3-57
SIMPLEX CHANNEL PROGRAMMING . . . . . . . . .3-59
SEMI-DUPLEX CHANNEL PROGRAMMING . . . . .3-60
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KFS 594 CONTROL DISPLAY UNIT OPERATION . . . . . . .3-62
KFS 594 CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . .3-62
OFF/VOLUME . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-62
SQUELCH/OPTIONAL SELCAL . . . . . . . . . . . . . . .3-63
MODE SELECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-63
USB MODE A3J MODE . . . . . . . . . . . . . . . . . . . . . .3-63
DIRECT TUNING A FREQUENCY . . . . . . . . . . . . .3-64
CHANNEL OPERATION AND PROGRAMMING . .3-66
SIMPLEX CHANNEL PROGRAMMING . . . . . . . . .3-67
SEMI-DUPLEX CHANNEL PROGRAMMING . . . . .3-68
CLARIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-70
MARITIME RADIOTELEPHONE NETWORK . . . . .3-71
KFS 594 OPERATIONAL NOTES: . . . . . . . . . . . . . . . .3-73
SECTION IV
HF COMMUNICATIONS SERVICES DIRECTORY . . . . .4-1
SECTION V
ICAO ENROUTE NETWORKS . . . . . . . . . . . . . . . . . . . .5-1
HF RADIOTELEPHONE NETWORKS MAP . . . . . . . . . . .5-3
SECTION VI
ARINC OPERATIONAL CONTROL SERVICES . . . . . . . .6-1
DESCRIPTION OF SERVICES . . . . . . . . . . . . . . . . .6-1
ARINC OPERATING PROCEDURES . . . . . . . . . . . .6-2
AUTHORIZED CONNECTIONS . . . . . . . . . . . . .6-2
GROUND-TO-AIRCRAFT CALLS . . . . . . . . . . . .6-3
ARINC LONG DISTANCE CONTROL FACILITIES . .6-5
SECTION VII
ITU MARITIME RADIOTELEPHONE STATIONS . . . . . .7-1
DESCRIPTION OF SERVICES . . . . . . . . . . . . . . . . . . . .7-1
AT&T HIGH SEAS RADIOTELEPHONE SERVICE .7-2
AT & T COAST STATION COVERAGE MAP . . . . . .7-3
COAST STATION COVERAGE & INFORMATION . .7-3
AIRCRAFT REGISTRATION . . . . . . . . . . . . . . . . . . .7-4
USING THE HIGH SEAS RADIO NETWORK . . . . . .7-4
PLACING AIRCRAFT-TO-GROUND CALLS . . .7-4
RECEIVING HIGH SEAS CALLS . . . . . . . . . . . .7-5
PLACING GROUND-TO-AIRCRAFT CALLS . . .7-5
TELEPHONE SERVICES OFFERING . . . . . . . .7-5
HIGH SEA RATE STRUCTURE . . . . . . . . . . . . .7-6
TRAFFIC LIST BROADCAST . . . . . . . . . . . . . . .7-6
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AT&T HIGH SEAS COAST STATIONS . . . . . . . . . . .7-6
A FEW VITAL FACTS . . . . . . . . . . . . . . . . . . . . .7-6
COAST STATION KMI-CALIFORNIA . . . . . . . . .7-7
COAST STATION WOO - NEW JERSEY . . . . . .7-8
COAST STATION WOM - FLORIDA . . . . . . . . . .7-9
MOBILE MARINE RADIO, INC. . . . . . . . . . . . . . . . .7-11
WORLD WIDE LISTING OF PUBLIC
CORRESPONDENCE STATIONS . . . . . . . . . . . . .7-12
MARITIME RADIO CHANNEL DESIGNATIONS . . .7-14
SECTION VIII
TIME & FREQUENCY STANDARD . . . . . . . . . . . . . . . .8-1
DESCRIPTION OF SERVICES . . . . . . . . . . . . . . . . . . . .8-1
WWV AND WWVH . . . . . . . . . . . . . . . . . . . . . . . . . .8-1
TIME ANNOUNCEMENTS . . . . . . . . . . . . . . . . . . . .8-2
GEOPHYSICAL ALERTS ON WWV . . . . . . . . . . . . .8-3
OMEGA NAV SYSTEM STATUS REPORTS . . . . . . .8-5
GLOBAL POSITIONING SYSTEM (GPS)
STATUS ANNOUNCEMENTS . . . . . . . . . . . . . . . . . .8-5
MARINE STORM WARNINGS . . . . . . . . . . . . . . . . .8-5
TIME AND FREQUENCY SERVICES WORLDWIDE 8-7
SECTION IX
VOLMETS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-1
SECTION X
EMERGENCY FREQUENCIES . . . . . . . . . . . . . . . . . . .10-1
INTERNATIONAL DISTRESS FREQUENCY . . . . . . . .10-1
SECTION XI
SHORTWAVE BROADCASTS . . . . . . . . . . . . . . . . . . .11-1
SECTION XII
MANUAL AND ALE PROGRAMMING . . . . . . . . . . . . . .12-1
MANUAL DATABASE PROGRAMMING . . . . . . . . .12-1
MANUAL CHANNEL PROGRAMMING . . . . . .12-1
PROGRAMMING FREQUENCY . . . . . . . . . . . .12-2
PROGRAMMING MODULATION TYPE . . . . . .12-2
ALE DATABASE PROGRAMMING . . . . . . . . . . . . .12-2
SYSTEM PROGRAM PAGE . . . . . . . . . . . . . . .12-3
AMD TRANSMIT MESSAGES . . . . . . . . . . . . .12-5
OPERATION PARAMETERS . . . . . . . . . . . . . .12-5
PROGRAMMING OPERATION
PARAMETERS . . . . . . . . . . . . . . . . . . . . . .12-6
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ALE CHANNEL DATABASE . . . . . . . . . . . . . . .12-7
PROGRAMMING ALE CHANNELS . . . . . .12-7
PROGRAMMING CHANNEL GROUPS . .12-7
PROGRAMMING THE SCAN LIST . . . . . . .12-8
ALE ADDRESSES . . . . . . . . . . . . . . . . . . . . . . .12-8
ALE ADDRESS PROGRAM PAGE . . . . . .12-9
PROGRAMMING A SELF ADDRESS . . . .12-9
PROGRAMMING A SINGLE ADDRESS .12-10
PROGRAMMING A STAR NETWORK
ADDRESS . . . . . . . . . . . . . . . . . . . . . . . . .12-11
PROGRAMMING A GROUP ADDRESS .12-12
PROGRAMMING A SPECIAL ADDRESS
TYPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-13
SECTION XIII
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-1
APPENDIX A: GEOPHYSICAL ALERT BROADCASTS 13-1
VOICE MESSAGE GEOPHYSICAL ALERTS ON WWV 13-1
GLOSSARY OF TERMS FOR THE SESC WWV
VOICE MESSAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-2
APPENDIX B: FREQUENCY STANDARD SERVICES 13-4
APPENDIX C: ADDITIONAL MATERIAL ON HF RADIO 13-5
APPENDIX D: FCC APPLICATION . . . . . . . . . . . . . . . .13-6
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Introduction
INTRODUCTION
KHF 950/990 COMMUNICATIONS TRANSCEIVER
High frequency (HF) communications made easy, that’s what the
King KHF 950/990 HF SSB Transceiver is all about.
The KHF 950/990 is a compact, lightweight system to provide an
extensive range of operator benefits. It is designed with international
flight operations in mind to provide superior long range communications.
A basic KHF 950/990 system consists of either three or four units
including your choice of either a miniature Gold Crown III style (KFS
594) or two different Dzus rail-mounted control display units (KCU
951 & KCU 1051). Additional hardware is available to allow the KHF
950 system to tune most shunt and notch antennas used on some
corporate jet aircraft. It can also be installed in a dual configuration
sharing the same HF antenna, and yet provide a dual receive capability which many corporate users find highly desirable. The KCU
1051 will provide Automatic Link Establishment (ALE). This allows
automatic selection of the optimum frequency and linking to another
ALE system.
Microprocessor control of vital frequency selection functions provides
an unprecedented number of programmable channels, greater ease
of changing these channels on the ground or in the air, and direct
access to a full 280,000 operating frequencies from 2.0 to 29.9999
MHz. The control heads provide extreme ease in fully utilizing the
semi-duplex channels of the maritime radiotelephone (public correspondence) network.
There are three types of control heads available. The KCU 1051
control display unit provides Automatic Link Establishment (ALE)
capability. The KCU 1051 is a Dzus rail-mounted unit with 200 programmable channels, 100 for manual channels and 100 for ALE
channels, also all 245 ITU channels used by the maritime radiotelephone network are preprogrammed into non-volatile memory. No
additional programming of ITU channels is ever required. With the
KCU 951 Dzus rail-mounted control display unit, 99 pilot programmable channels are available. With the KFS 594 miniature control display unit and its associated remote adapter unit, 19 pilot programmable channels are available and, in addition, all 245 ITU channels used
by the maritime radiotelephone network are preprogrammed into
nonvolatile memory. When the KFS 594 Control Display Unit is used,
no additional programming of ITU maritime radiotelephone network
channels is ever required.
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Introduction
High frequency radio opens a world of communication possibilities to
the pilot and his passengers, including long range contact with air
traffic control agencies over thousands of miles away, time and frequency standard broadcasts, Omega navigation station status
reports, weather and marine storm warnings, radiotelephone service
for personal messages and ARINC operational control services for
messages relating to flying operations.
The first section of this pilot’s guide deals with high frequency communications in general. A basic understanding of single sideband and
some of the conditions which influence HF communications is important to using the KHF 950/990 effectively and obtaining the maximum
benefit from its extensive capabilities.
The second section details the actual operation of the KHF 950/990
system and the final section of this pilot’s guide covers the wide variety of HF communications services which are available to the pilot
using the Bendix/King KHF 950/990.
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SECTION I
CHARACTERISTICS OF HF SSB
COMMUNICATIONS WITH AUTOMATIC
LINK ESTABLISHMENT.
ACRONYMS AND DEFINITIONS
ALE Automatic Link Establishment
AMD Automatic Message Display
CDU Control Display Unit
HF High Frequency
KPN King Part Number
LQA Link Quality Analysis
PC IBM compatible Personal Computer
REFERENCES
The following documents are referenced by this document.
Description
MIL-STD-188-141A Appendix A Notice 2
Automatic Link Establishment System, 10 September 1993
Federal Standard 1045A
Telecommunications:HF Radio Automatic LinkEstablishment,
24 January 1990
HF SSB COMMUNICATIONS
High frequency single side band communications achieve reliable
long range transmission and reception over distances of thousands
of miles. The primary reason is due to skywave propagation which
allows HF radio waves which are beamed toward outer space to be
reflected back toward the earth’s surface by the ionosphere. Another
reason is because of a transmission process known as single sideband which puts all the transmitter’s power into sending just a radio
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Description
wave containing the intelligence to be communicated. Both of these
make HF radio highly useful to aircraft flying over water or desolate
land areas when they are out of reach of VHF communications which
are limited to line of sight transmissions. A familiarization with frequency, skywave propagation, amplitude modulation, single sideband
operation, suppressed carrier versus reduced carrier, simplex and
semi-duplex operation, and automatic link establishment will make
this pilot’s guide easier to use and understand.
The following explanations will help provide a base to build on as you
acquire experience in operating your KHF 950/990. If you have had
experience with HF radio previously, the following material will serve
as a review.
FREQUENCY
The frequency of a radio wave is the number of cycles of that radio
wave which pass a given point within one second. The longer the
wavelength, the lower the frequency. The frequency is often
expressed as cycles per second, with one complete wave representing a cycle. The term hertz (Hz) is more commonly used today to
represent one cycle per second. Expression of the measurement Hz
has a shorthand of its own. When thousands of Hz are expressed,
they are designated kilohertz (kHz), and millions of Hz as mega-
hertz (MHz). Thus the notation 29.9999 MHz represents a signal
which is passing a given point at 29,999, 900 cycles per second.
Expressed in kHz, the same Figure would read 29,999.9 kHz representing 29,999.9 thousand cycles per second. In using HF, you will
encounter both MHz and kHz notations for frequencies. KFS 594 and
KCU 951 control display units always express frequencies in terms of
kHz. The KCU1051 control display unit always expresses frequencies in terms of MHz.
The high frequency (HF) band , with which we are primarily con-
cerned in this pilot’s guide, covers from 2.0 MHz to 30 MHz (2,000
kHz to 30,000 kHz). The HF band lies between the medium frequency (MF) band and the very high frequency (VHF) band. Pilots are
familiar with the characteristics of MF frequencies through the use of
ADF equipment and know that these signals hug the ground and are
sensitive to variations in terrain and to atmospheric disturbances. On
the other hand, pilots know that VHF frequencies such as are used in
VOR navigation and normal communications with Air Traffic Control
facilities generally travel line-of-sight range and are not greatly affected by atmospheric disturbances. As will be discussed next, HF has
its own characteristics which allow long range communications to
take place.
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Description
SKYWAVE PROPAGATION - WHICH FREQUENCY TO
USE?
As mentioned earlier, HF’s primary method of travel or propagation is
via skywaves which are radio waves that start out radiating into
space and are reflected off the ionosphere back to the earth’s surface. This reflecting of signals makes communications over very long
distances-under ideal conditions more than 4,000 miles and typically
in excess of 2,000 miles-possible. Because of variations in the ionosphere, HF communications require more analysis of conditions and
operational decisions (such as frequency selection) than VHF communications.
The ionosphere is a multi-layered band of electrically charged particles surrounding the earth. It varies in height above the surface of the
earth from approximately 30 to over 400 miles. The height and intensity varies from one location to the next and according to the season
of the year and the time of day.
Because HF radio waves depend upon the ionosphere for reflection,
their propagation is affected by changes in the ionosphere. It is
changes in the density of the electrically charged particles in the
ionosphere which cause propagation to improve or deteriorate. Since
the ionosphere is formed primarily by the action of the sun’s ultraviolet radiation, its thickness changes in relation to the amount of sunlight passing through it. Sunlight-induced ionization increases the particle density during the day and the absence of it reduces the particle
density at night. At midday, when the sun’s radiation is at its highest,
the ionosphere’s thickness may expand into four layers of ionized
gas. During the nighttime hours, the ionosphere diminishes, normally
merging into just one layer.
Solar disturbances including solar flares and magnetic storms can
cause propagation of HF radio waves to deteriorate rapidly. HF signals can also suffer interference from such atmospheric disturbances
as precipitation and thunderstorms.
The net result of all these factors is that because the ionospheric and
atmospheric conditions are constantly changing, HF communications
can vary in quality and strength. The signal received on the KHF
950/990 may be accompanied by a considerable amount of static
from atmospheric disturbances, or it may fade in and out at times
because each radio wave which hits the changing ionosphere may
be reflected differently. Your reception and transmission success may
vary from loud and clear to nonexistent depending on your selection
of frequency and the conditions in the atmosphere and the ionos-
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Description
phere. One of the best things the pilot can do to assure the best possible HF communications, based on existing HF propagation conditions, is to select the proper frequency. A good rule of thumb for the
time of day is that the higher frequencies are best during daylight (10
to 29.9999 MHz) and lower frequencies work best at night (2 to 10
Mhz).
This rule of thumb can be explained by a mirror analogy. It is the
electrically charged particles in the ionosphere which reflect or bend
radio waves back toward earth like a mirror reflects light. Sunlight
induces ionization and increases the density of these particles in the
ionosphere during the day. The mirror becomes thicker and it reflects
higher frequencies better. When the sun goes down the density of
charged particles decreases and the ionosphere becomes a mirror
that can only reflect lower frequencies in the HF band.
For any one particular frequency, as the angle at which an HF radio
wave hits a layer of the ionosphere is increased, a critical anglewill
be reached from which the wave will just barely manage to be reflected back to earth (Figure 1-1). Waves entering at sharper angles than
this will pass through this layer of the ionosphere and be lost in space
(or may reflect off another layer of the ionosphere).
Changing the frequency under the same conditions will change the
critical angle at which the HF radio waves will be reflected back to
earth. The highest frequency which is reflected back to the earth is
called the maximum useable frequency (MUF). The best HF communications are usually obtained using a frequency as close to the MUF
as possible since radio waves higher than this frequency are not
reflected and radio waves lower than this frequency will be partially
absorbed by the ionosphere.
You should also be aware of the possibility that you or the ground
station you are calling may be in a quiet zone. The linear distance
from the point of transmission to the point where the skywave returns
to earth is called the skip distance. There may be a quiet zone
between the end of the ground wave and the return of the skywave.
No communication can take place in this area. At any time, day or
night, there is a “window” of useable frequencies created by the
reflecting properties of the ionosphere. At night this “window” will normally be in the lower range of HF frequencies, and during the day it
will be in the higher range of frequencies.
Normally you will not know what the MUF is at any particular time and
location unless you have a table of propagation forecasts. Just
remember that the higher frequencies in the “window” of useable fre-
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Description
quencies are likely to be the most effective. The closer a frequency is
to the MUF, the better it is likely to be.
The effect of solar disturbances including solar flares and magnetic
storms is to change the particle density in the ionosphere. Therefore,
the “window” of useable frequencies may begin to close, with radio
waves of frequencies in the lower range dropping out first as they are
absorbed by the ionosphere.
E
N
O
Z
IP
K
IONOSPHERE
AIRCRAFT
CRITICAL ANGLE
E
I
U
Q
E
C
N
A
T
S
DI
E
R
I
S
DE
EARTH
T
Z
O
N
E
S
K
Y
D
P
AT
H
W
D
A
I
S
V
T
E
A
N
C
E
AIRCRAFT
Z
O
N
E
REFRACTION
E
V
A
S
W
M
D
U
N
M
I
U
IN
O
M
R
G
Figure 1-1 Effects Of Different Skywave Paths
Next, the radio waves of upper frequencies in the useable “window”
may start to penetrate the ionosphere and go into outer space. It is
even possible for the entire “window” to close, particularly if you are
flying in a polar region in latitudes above 60 degrees north or 60
degrees south. Solar disturbances have the most negative effects on
HF communications in these regions.
If you are flying in polar regions and are having difficulty raising any
ground station located in the same region, remember this: even
though the “window” of useable frequencies may have closed in the
polar regions, another “window” may be open in regions closer to the
equator which are less affected by solar disturbances. Try calling a
station closer to the equator in latitudes lower than 60 degrees north
or 60 degrees south, and use a higher frequency. If you can raise a
station in these areas, that station may be able to relay your message.
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There are even times when solar disturbances improve the usability
of higher frequencies in the HF band, particularly in equatorial
regions. Another phenomenon which occurs during solar disturbances may allow you to communicate with a station even though the
“window” is closed. This is known as scatter propagation, in which a
radio wave is broken up in the ionosphere and scatters in various
directions. Refer to the discussion of geophysical alerts in Appendix
A for information on broadcasts which announce solar disturbance
phenomena, and how to interpret these broadcasts.
Because frequency propagation cannot be predicted with total accu-
racy, ground stations responsible for aircraft HF communications will
typically operate on several different frequencies within the HF band.
The pilot is then able to choose the optimum communication frequency for the existing ionospheric conditions.
One feature that will be particularly useful when a trial and error
method is used to find an HF frequency which is working well. This is
the system’s capability to be programmed by the pilot with 99 channels (using the KCU 951 Control Display Unit), 100 channels (using
the KCU1051 control display unit) or 19 (using the KFS 594 miniature
control display unit). Rather than having to select the four to six digits
each time you want to try another frequency, you can preprogram the
frequencies you need to contact a particular ground station. Then if
you call and fail to get through, you just change to another channel.
(Automatic channel selection for optimum communications reliability
is simplified with the addition of Automatic Link Establishment (ALE),
available on the KCU 1051 Control Display Unit.
NOTE: It is advisable to program at least three frequencies for each
station you plan to contact, in case one frequency suddenly becomes
unusable. During times of solar disturbances, a useable frequency
can fade out in less than a minute. And the “window” of useable frequencies can shift rapidly during solar disturbances or during sunset
and sunrise when the level of ionization in the ionosphere is changing rapidly.
Tables 1-1 and 1-2 show typical propagation distances after one
reflection from the ionosphere for various frequencies during different
hours of the day and for different seasons of the year. It may prove
helpful in selecting the optimum HF frequency for the communications distance your operation requires.
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Description
Frequency (kHz)
4000 8000 12000 16000
Propagation (Miles)
Min Max Min Max Min Max Min Max
Hours After Sunset
1 50 250 200 1000 500 3500 750 6000
2 100 600 250 1500 500 3500 750 6000
3 100 600 250 2000 500 3500
4 100 800 250 2500
5 100 1000 250 2500
6 100 1500 400 3000
7 100 1500 500 3500
8 250 2000 750 4000
9 250 2500 750 4000
10 250 2500 750 4000
11 100 1000 500 2500
Hours After Sunrise
1 100 500 400 2000
2 0 100 400 2000
3 0 100 250 1500
4 0 100 250 1500 500 1000
5 0 100 250 1500 500 1500
6 0 100 250 1500 500 2500 750 4000
7 0 100 250 1500 500 3500 750 4000
8 0 100 250 1500 500 3500 750 4000
9 0 100 250 1500 500 3500 750 4000
10 0 100 250 1500 500 3500 750 4000
11 0 100 150 500 500 3500 750 6000
12 0 200 150 500 500 3500 750 6000
13 50 250 150 750 500 3500 750 6000
Table 1-1 Typical Frequency Propagation Spring And Summer
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Description
Frequency (kHz)
4000 8000 12000 16000
Propagation (Miles)
Min Max Min Max Min Max Min Max
Hours After Sunset
1 100 600 400 2000 500 3500 750 6000
2 100 800 400 2000 500 4000 750 6000
3 100 1000 400 2000 500 4000
4 100 1000 400 2500 500 4000
5 100 1000 400 3000 500 4000
6 100 1500 400 3500
7 250 2000 400 4000
8 250 2500 500 4000
9 500 3000 500 4000
10 500 4000 500 4000
11 500 3000 750 5000
12 250 2500 750 5000
13 250 1500 500 2500
Hours After Sunrise
1 100 1000 400 2000
2 100 500 400 2000
3 0 100 400 2000 3500 750 4000
4 0 100 400 2000 500 3500 750 4000
5 0 100 250 1500 500 3500 750 4000
6 0 100 250 1500 500 3500 750 4000
7 0 100 250 1500 500 4000 750 5000
8 0 100 250 1500 500 4000 750 5000
9 0 100 250 1500 500 4000 750 6000
10 0 100 250 1000 500 3500 750 6000
11 0 250 250 1500 500 3500 750 6000
Table 1-2 Typical Frequency Propagation For Fall And Winter
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Description
WHY SINGLE SIDEBAND IS IMPORTANT IN HF
COMMUNICATIONS
As mentioned earlier, there are two characteristics of HF SSB communications which allow long range capability. Skywave propagation
has been discussed in detail. The other characteristic is a transmission process known as single sideband. Single sideband (SSB) high
frequency (HF) communications was developed in the early 1950’s
as a means of increasing the effective range of HF signals. The KHF
950/990 is capable of both amplitude modulation (AM) operation,
such as is used in conventional VHF aircraft communications, and of
SSB operation.
AMPLITUDE MODULATION (AM)
In order to understand SSB operation, a discussion of AM operation
is helpful. Amplitude Modulation (AM) is a transmission process in
which the selected frequency (called the carrier frequency) and two
sidebands (which are frequencies above and below the carrier frequency) are generated and transmitted. (Figure 1-2.) It takes about
two-thirds of the transmitter’s power just to transmit the carrier frequency, yet the carrier does not contain any of the intelligence to be
communicated. Each of these sidebands contains all the intelligence
to be communicated. Standard broadcast stations (550-1600 kHz)
and short-wave broadcasts use AM since it allows simpler receivers.
NOTE: The use of lower sideband isn’t normally authorized for airborne HF use. It is normally disabled in the KHF 950/990, but can be
enabled for those who are authorized to use it.
AMPLITUDE MODULATION (AM)
fc = carrier frequency
fm = modulating frequency (voice)
fc-fm
LSB
fc fc+fm
USB
Figure 1-2 Amplitude Modulation
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KHF 950/990 Pilots Guide
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Description
SINGLE SIDEBAND (SSB)
fc = carrier frequency
fm = modulating frequency (voice)
fc-fm
LSB
fc fc+fm
USB
SINGLE SIDEBAND OPERATION
By electronically eliminating the carrier wave and one sideband, a
single sideband transmitter manages to pack all of its power in transmitting the remaining single sideband. (Figure 1-3). Either the upper
sideband (USB) or the lower sideband (LSB) can be used since each
sideband contains all the required intelligence. However, from a practical standpoint the USB is used almost exclusively in airborne HF
SSB operations and the LSB may be disabled. Upon receiving this
SSB signal, the receiver then generates the carrier frequency internally and combines it with the one sideband in such a way that the
intelligence (voice) can be heard and understood by the pilot.
SINGLE SIDEBAND (SSB)
Figure 1-3 Single Sideband
The result is that an SSB system has the effective transmit power of
AM units having many more times the transmitter power. Also, SSB
communications allow the frequency band to be utilized more efficiently since the space or “bandwidth” of only one sideband rather
than two sidebands is required to transmit the message.
SUPPRESSED CARRIER VS. REDUCED CARRIER
The single sideband (SSB) operation just described with the carrier
frequency virtually eliminated is actually referred to as single sideband suppressed carrier and is designated A3J. If just a small portion
of the carrier is transmitted along with the sideband, the operation is
referred to as single sideband reduced carrier and is designated A3A.
A3A was previously used in maritime radiotelephone but is not used
currently. Regulations still require its inclusion in equipment used in
conjunction with maritime radiotelephone. A3A is normally disabled
on the KCU 1051, but is harness selectable. A3A is normally internally disabled on the KCU 951 Control Display Unit. If it has been
enabled it is annunciated when both “AM” and “USB” are simultaneously displayed. The KFS 594 miniature control display unit allows
the A3A mode to be selected by rotating the mode selector to the
“A3A” position.
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Description
SIMPLEX AND SEMI-DUPLEX OPERATION
The KHF 950/990 is capable of both simplex and semi-duplex operation.
Simplex operation means that communication signals are transmitted
and received on the same frequency. Simplex operations are used
when communicating with Air Traffic Control (ATC), for example.
Semi-duplex operation means that messages are transmitted on one
frequency and received on another. The HF operator selects separate transmit and receive frequencies, then keys the microphone to
transmit and releases the push-to-talk switch to receive. Semi-duplex
operation is usually used for maritime radiotelephone (public correspondence) communications.
AUTOMATIC LINK ESTABLISHMENT (ALE)
ALE is an HF radio management system that selects the optimum
frequency of transmission, places automatic or manual calls to link
one or more users, and communicates digital messages. The ALE
specification and waveform were adopted as standards by the US
government in September, 1988 as MIL-STD 188-141A (Appendix A)
for the military and as Federal Standard 1045 for civilian government
agencies.
The advent of ALE technology has changed HF communications by
allowing systematic and automatic real-time evaluation of HF communications paths, permitting automatic frequency selection.
Because of this, the operation of an HF radio with Automatic Link
Establishment is greatly simplified and the communications reliability
is increased. A KCU 1051 CDU is required when Automatic Link
Establishment features are desired.
FUNCTIONS OF HF RADIO AUTOMATION
There are many functions, that the HF Radio Automatic Link
Establishment System performs for you. They are Selective Calling
and Handshake, Scanning, Sounding, Polling, and Link Quality
Analysis and Channel Selection
SELECTIVE CALLING AND HANDSHAKE - The selective calling
and handshake function enables the establishment of a link between
two radios. It includes digital address selective calling, followed by an
exchange consisting of a response and acknowledgment, to produce
a handshake (the establishment of a communications link).
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Description
SCANNING - All available stations continuously and rapidly scan
their receivers through their channels, seeking ALE calls. At any
time, a calling station may slowly scan its transmitter through their
channels, calling on each one, until answered on a channel that supports contact. This function enables the selection of a channel that
successfully supports contact, despite variations in propagation,
occupancy, and other traditional HF challenges.
SOUNDING - Sounding is a special beacon-like technique that
assists all listening stations in measuring the propagation from the
sounding station. The sounding station transmits its address on all
channels, and the other stations measure the quality of the received
signal. Sounding stations provide this service to other stations and
do not use the information themselves.
POLLING - Polling enables two radios to measure the propagation
characteristics for each channel’s receive and transmit path. Then the
information is stored in non-volatile memory.
LINK QUALITY ANALYSIS AND CHANNEL SELECTION - This
function enables the radio to measure the quality of the received signals (and thus the available links) and to select the best channel for
calling and communicating. This function allows a calling station to
initiate calling on the best known working channel and thereby speed
linking. It also minimizes unnecessary calling on marginal channels,
when a transmitting station knows how well its signal is being
received by the intended stations.
HOW ALE ASSURES THAT THE BEST COMMUNICATIONS LINK IS CHOSEN AUTOMATICALLY EVER Y TIME
With Automatic Link Establishment on the job, the radio constantly
scans the available channels for an ALE transmission. ALE transmissions are digitized HF signals. When an ALE transmission is
detected, the signal-to-noise ratio of that signal is retained in memory.
The next time a call is made, the radio uses that signal-to-noise ratio
to determine the best channel to use. This way the best channel is
always the one used, allowing you to have the best possible communications link all the time, in spite of the constantly changing thickness, density, and reflectivity of the ionosphere (a condition that is not
controllable). Every frequency reacts a little differently to random
changes in the ionosphere. The link quality for one frequency may
increase while it may decrease for another for the same random
changes.
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Description
ALE relieves you of the burden of trying to manually detect and
compensate for random changes in the ionosphere and of
searching for a good channel to use. It lets you concentrate on
the message to be sent.
During the time when no call is present, the radio is squelched to
reduce noise in the cockpit. After a call is received, a sound like a
phone ringing is heard, the radio un-squelches, and you can commence a normal HF communication. ALE relieves you of the bur-
den of monitoring the radio for the presence of an HF call.
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Description
This Page Intentionally Left Blank
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KHF 950/990 Pilots Guide
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Description
SECTION II
KHF 950/990
SYSTEM DESCRIPTION.
The KHF 950/990 is a solid-state HF single sideband transceiver system. The KHF 950 system can be controlled by either a KCU 1051
Dzus rail-mounted control display unit, a KCU 951 Dzus rail-mounted
control display unit, or a miniature KFS 594 Gold Crown III style control display unit. The KFS 594 requires an extra remote unit (KA 594)
which contains electronics associated with this miniature panelmounted control display unit. All the control units work in conjunction
with a KAC 952 power amplifier/antenna coupler and a KTR 953
receiver/exciter.
The KHF 990 system can be controlled by either a KCU 1051 or the
KFS 594 Control Display Unit. These control units work with the KAC
992 Antenna Coupler and a KTR 993 receiver/transmitter.
KCU 1051 CONTROL DISPLAY UNIT
The KCU 1051 Control Display Unit (Figure 2-1) adapts the existing
KHF 950 and KHF 990 High Frequency Radio systems for use with
Automatic Link Establishment, providing the pilot’s display and control interface. Frequency, channel, mode, ALE address, audio gain,
and squelch level selections are entered via its controls. Fault monitoring and fault annunciation are also provided by the KCU 1051.
The KCU 1051 provides the pilot access to 100 manual channels,
100 ALE channels, and 245 ITU channels to interface with maritime
radiotelephone networks. The KCU 1051 uses a liquid crystal display
to show frequency, channel, and mode of operation. The manual
and ALE channels can be easily programmed by the pilot on the
ground or in the air, and the nonvolatile memory stores this information even when the system is turned off.
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KHF 950/990 Pilots Guide
2-1
Description
Display
The display screen is capable of displaying 2 lines of 16
(upper or lower case) characters. Information is
presented in formatted pages. The main display pages
are accessed by placing the cursor over the
operations/mode field (ALE) and rotating the VAR knob
until the desired page is displayed. To display a subpage of a main page see Secton III, Operation..
VOLUME knob
The VOLUME knob performs two functions.
Rotate the VOLUME knob to control the
audio output level. Push the VOLUME knob
to the in position to apply power to the unit or
pull the VOLUME knob to the out position to
remove power from the unit.
SQUELCH knob
Rotate SQUELCH
knob to control
the squelch
threshold level.
CURSOR knob
Rotate CURSOR knob to move
cursor from one field to next
field or one character to next
character when in CHAR MODE.
VAR knob
The VAR knob performs two functions.
Rotate knob to vary data under cursor.
Toggle the momentary switch. VAR knob
to the in position to select CHAR cursor
mode and then toggle again to select
FIELD cursor mode.
HF ALE
SCAN
VOL SQL CRSR VAR
MSG CLR ENT
PUSH
ON
PUSH
CHAR
B
OOOO Scan 100RM
ALE15CHARADDRESS
CLR key
By pushing the CLR
key you can cancel
changes made by the
operator or exit the
programming page.
ENT key
Pressing the ENT key
stores changes made
to the cursored field.
MSG key
The MSG key displays
the message page
where system
messages and ALE
AMDs can be reviewed
SCAN key
The SCAN key starts and
stops scanning and it causes
the radio to hang-up from an
ALE link. The SCAN key can
also be used to abort an
initiated call.
2-2
Figure 2-1 KCU 1051 Control Display Unit
KHF 950/990 Pilots Guide
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Description
KFS 594 CONTROL DISPLAY UNIT
The KFS 594 (Figure 2-2) provides the pilot with access to 19 programmable channels plus a full 280,000 operating frequencies in the
2.0 to 29.9999 MHz range. In addition, all 245 ITU maritime radiotelephone network (public correspondence) channels have been stored
in nonvolatile memory along with the appropriately paired transmit
and receive frequencies. Thus, to call up a radiotelephone channel,
the pilot need only select “423” for WOM in Ft. Lauderdale, Fla., for
example, rather than having to program 4425.6 kHz as the transmit
frequency and 4131.2 kHz as the receive frequency (see WOM channel/frequency chart, Figure 7-3). The KFS 594 is a miniature Gold
Crown III style control display unit which uses electronic gas discharge readouts to display frequency and channel information. All
necessary controls for operation of the KHF 950/990 system, including programming of all preset channels, are on the KFS 594.
The 19 channels can be easily programmed by the pilot on the
ground or in the air, and the nonvolatile memory stores this information and the 245 ITU maritime radiotelephone channels even when
the system is turned off.
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Description
1
S
T
HF
OFF
TELAM
USB
LSB
A3J
A3A
VOL
SQ
2236
CH
M
H
Z
K
H
Z
KFS 594 in
A3J (or A3A)
MODE
Mairitime
radiotelephone ITU
channel number
appears in this area
of the display when
EMISSION MODE
switch is in A3J or
A3A position.
1
S
T
HF
OFF
TELAM
USB
LSB
A3J
A3A
VOL
SQ
1231
12 - 31
CH
M
HZT
X
K
H
Z
Pilot programmed
channel number
appears in this area
of the display when
using one of the 19
programmable
channels.
Gas discharge
readouts display all
frequencies and
preset channel
numbers.
Last for digits (kHz)
of operating
frequency are
display in this area
of the display with
EMISSION MODE
switch in LSB*, USB
or AM position.
OFF/VOLUME knob
(inner concentric)
turns system on and
adjusts audio
volume.
SQUELCH knob
(outer concentric)
helps reduce
background noise
when not receiving
a signal.
EMMISSION MODE
switch (outer
concentric) selects
lower sideband
(LSB), AM modes,
and a choice of
either A3J or A3A in
maritime
radiotelephone
network channels.
FREQUENCY/CHANNEL
CONTROL knob (inner
concentric) allows the pilot
to perform a variety of
channel and frequency
changing functions.
Depressing switch causes
flashing "cursor" to move to
the digit that the pilot desires
to change. Appropriate
frequency or channel is then
selected with rotary action.
This switch also serves as
the clarifier function to
adjust receive frequency and
improve speech quality in
single sideband operating
mode.
STO (store) switch
stored displayed
frequency in memory.
When pressed
simultaneously with
microphone push-to-talk
switch, transmits 1,000
Hz "operator attention"
tone as required by
some Canadian
radiotelephone stations.
Photocell dims
display
automatically.
Smaller gas
discharge
characters display
transmit indication.
With EMMISSION
MODE switch in
LSB*, USB or AM
position, the first
one or two digits
(MHz) of the
operating frequency
are displayed here.
Dash indicates unit
is in the PROGRAM
MODE.
2-4
Figure 2-2 KFS 594 Control Display Unit
KFS 594 in A3J (or A3A) Mode
Figure 2-3 KFS 594 in A3J (or A3A) Mode
KHF 950/990 Pilots Guide
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Description
KCU 951 CONTROL DISPLAY UNIT
The KCU 951 (Figure 2-4) provides the pilot access to 99 programmable channels plus a full 280,000 operating frequencies in the 2.0 to
29.9999 MHz range. It provides semi-duplex capability through the 99
programmable channels to interface with maritime radiotelephone
networks. A Dzus rail-mounted control display unit, the KCU 951,
uses electronic gas discharge readouts to display frequency, channel
and mode of operation. All necessary controls for operation of the
KHF 950/990 system, including programming of all preset channels,
are on the KCU 951. The 99 channels can be easily programmed by
the pilot on the ground or in the air, and the nonvolatile memory
stores this information even when the system is turned off.
Smaller gas
Gas discharge
readouts display all
frequncies and
preset channel
numbers.
discharge
characters display
emmision mode,
transmit indicator
and program mode
indication.
ı
12345.6 99
USBAMLSB PGMTX
PULL
CLARIFIER knob adjusts receive frequency to
improve speech quality in a single sideband
operating mode. Use of this control is only
required when station-to-station frequency
difference is significant.
FREQ KHZ CHANNEL
CLARIFIER
SQUELCH knob
helps cut out
background noise
when not
receiving a signal.
SQUELCH
Photocell
dims display
automatically.
OFF/VOLUME
knob turns
system on and
adjusts audio
volume.
OFF
VOLUME
STO (store)
switch stores
displayed
frequency and
emmission mode
in memory.
EMMISSION MODE
switch selects lower
sideband (LSB
where aproved),
upper sideband
(USB) or AM
modes.
HF
MODE FREQ CHAN
STO PGM
Concentric
Frequency/Channel
knobs set frequency
or select preset
channel.
FREQ/CHAN
(frequency/channel)
switch selects either
direct tuning or
preset channel
operation.
PGM (program)
switch permits pilot
to change frequncy
and emission mode
of preset channel.
Rev. 0
Dec/96
Figure 2-4 KCU 951 Control Display Unit
KHF 950/990 Pilots Guide
2-5
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