is module 04 - communications hardware

8/11/2019 Is Module 04 - Communications Hardware

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DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.

NONRESIDENT

TRAINING

COURSE September 1997

Information SystemsTechnician Training SeriesModule 4Communications Hardware

NAVEDTRA 14225

NOTICE

Any reference within this module to Radioman or the formerRadioman rating should be changed to Information SystemsTechnician and the Information Systems Technician (IT) rating.The subject matter presented relates to the occupational

standards for the IT rating.


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DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.

Although the words he, him, andhis are used sparingly in this course toenhance communication, they are notintended to be gender driven or to affront ordiscriminate against anyone.


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PREFACE

By enrolling in this self-study course, you have demonstrated a desire to improve yourself and the Navy.Remember, however, this self-study course is only one part of the total Navy training program. Practicalexperience, schools, selected reading, and your desire to succeed are also necessary to successfully round

out a fully meaningful training program.COURSE OVERVIEW : In completing this nonresident training course, you will demonstrate aknowledge of the subject matter by correctly answering questions on the following subjects:Communications Hardware, and Satellites and Antennas.

THE COURSE : This self-study course is organized into subject matter areas, each containing learningobjectives to help you determine what you should learn along with text and illustrations to help youunderstand the information. The subject matter reflects day-to-day requirements and experiences of personnel in the rating or skill area. It also reflects guidance provided by Enlisted Community Managers(ECMs) and other senior personnel, technical references, instructions, etc., and either the occupational ornaval standards, which are listed in the Manual of Navy Enlisted Manpower Personnel Classificationsand Occupational Standards , NAVPERS 18068.

THE QUESTIONS : The questions that appear in this course are designed to help you understand thematerial in the text.

VALUE : In completing this course, you will improve your military and professional knowledge.Importantly, it can also help you study for the Navy-wide advancement in rate examination. If you arestudying and discover a reference in the text to another publication for further information, look it up.

1997 Edition Prepared by RMCS(SW/AW) Deborah Hearn and

DPC(SW) Walter Shugar, Jr.

Published byNAVAL EDUCATION AND TRAINING

PROFESSIONAL DEVELOPMENTAND TECHNOLOGY CENTER

NAVSUP Logistics Tracking Number0504-LP-026-8640


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Sailors Creed

I am a United States Sailor.

I will support and defend theConstitution of the United States of

America and I will obey the ordersof those appointed over me.

I represent the fighting spirit of theNavy and those who have gonebefore me to defend freedom anddemocracy around the world.

I proudly serve my countrys Navycombat team with honor, courageand commitment.

I am committed to excellence andthe fair treatment of all.


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CONTENTS

CHAPTER PAGE

1. Communication shareware . . . . . . . . . . . . . . . . . . . .1-1

2. Satellites and Antennas . . . . . . . . . . . . . . . . . . . . . . .2-1APPENDIX

I. Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AI-1

II. Glossary of Acronyms and Abbreviations . . . . . . . . . . . . AII-1

III. References Used to Develop the TRAMAN. . . . . . . . . . . AIII-1

INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INDEX-1

NONRESIDENT TRAINING COURSE follows the index

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SUMMARY OF THE RADIOMANTRAINING SERIES

MODULE 1

Administration and SecurityThis module covers Radioman duties relating to

administering AIS and communication systems. Procedures and guidance forhandling of classified information, messages, COMSEC material and equipment,and AIS requirements are discussed.

MODULE 2

Computer SystemsThis module covers computer hardware startup, includingperipheral operations and system modification. Other topics discussed includecomputer center operations, media library functions, system operations, andtroubleshooting techniques. Data file processes, memory requirements, anddatabase management are also covered.

MODULE 3

Network CommunicationsThis module covers network administration, LANhardware, and network troubleshooting. Related areas discussed are network configuration and operations, components and connections, and communicationlines and nodes.

MODULE 4

Communications HardwareThis module covers various types of communications equipment, including satellites and antennas. Subjects discussedinclude hardware setup procedures, COMSEC equipment requirements, distress

communications equipment, troubleshooting equipment, satellite theory, andantenna selection and positioning.

MODULE 5

Communications Center OperationsThis module covers center operations,including transmit message systems, voice communications, center administration,quality control, and circuit setup/restorations. Guidelines for setting EMCON andHERO conditions and cryptosecurity requirements are also discussed.

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INSTRUCTIONS FOR TAKING THE COURSE

ASSIGNMENTS

The text pages that you are to study are listed atthe beginning of each assignment. Study thesepages carefully before attempting to answer thequestions. Pay close attention to tables andillustrations and read the learning objectives.The learning objectives state what you should beable to do after studying the material. Answeringthe questions correctly helps you accomplish theobjectives.

SELECTING YOUR ANSWERS

Read each question carefully, then select theBEST answer. You may refer freely to the text.The answers must be the result of your ownwork and decisions. You are prohibited fromreferring to or copying the answers of others andfrom giving answers to anyone else taking thecourse.

SUBMITTING YOUR ASSIGNMENTS

To have your assignments graded, you must beenrolled in the course with the NonresidentTraining Course Administration Branch at theNaval Education and Training ProfessionalDevelopment and Technology Center(NETPDTC). Following enrollment, there aretwo ways of having your assignments graded:(1) use the Internet to submit your assignmentsas you complete them, or (2) send all theassignments at one time by mail to NETPDTC.

Grading on the Internet: Advantages toInternet grading are:

you may submit your answers as soon asyou complete an assignment, and

you get your results faster; usually by thenext working day (approximately 24 hours).

In addition to receiving grade results for eachassignment, you will receive course completionconfirmation once you have completed all the

assignments. To submit your assignmentanswers via the Internet, go to:

http://courses.cnet.navy.mil

Grading by Mail: When you submit answersheets by mail, send all of your assignments atone time. Do NOT submit individual answersheets for grading. Mail all of your assignmentsin an envelope, which you either provideyourself or obtain from your nearest EducationalServices Officer (ESO). Submit answer sheetsto:

COMMANDING OFFICERNETPDTC N3316490 SAUFLEY FIELD ROADPENSACOLA FL 32559-5000

Answer Sheets: All courses include onescannable answer sheet for each assignment.These answer sheets are preprinted with yourSSN, name, assignment number, and coursenumber. Explanations for completing the answersheets are on the answer sheet.

Do not use answer sheet reproductions: Useonly the original answer sheets that weprovidereproductions will not work with ourscanning equipment and cannot be processed.

Follow the instructions for marking youranswers on the answer sheet. Be sure that blocks1, 2, and 3 are filled in correctly. Thisinformation is necessary for your course to beproperly processed and for you to receive creditfor your work.

COMPLETION TIME

Courses must be completed within 12 monthsfrom the date of enrollment. This includes timerequired to resubmit failed assignments.


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PASS/FAIL ASSIGNMENT PROCEDURES

If your overall course score is 3.2 or higher, youwill pass the course and will not be required toresubmit assignments. Once your assignmentshave been graded you will receive coursecompletion confirmation.

If you receive less than a 3.2 on any assignmentand your overall course score is below 3.2, youwill be given the opportunity to resubmit failedassignments. You may resubmit failedassignments only once. Internet students willreceive notification when they have failed anassignment--they may then resubmit failedassignments on the web site. Internet studentsmay view and print results for failedassignments from the web site. Students who

submit by mail will receive a failing result letterand a new answer sheet for resubmission of eachfailed assignment.

COMPLETION CONFIRMATION

After successfully completing this course, youwill receive a letter of completion.

ERRATA

Errata are used to correct minor errors or delete

obsolete information in a course. Errata mayalso be used to provide instructions to thestudent. If a course has an errata, it will beincluded as the first page(s) after the front cover.Errata for all courses can be accessed andviewed/downloaded at:

http://www.advancement.cnet.navy.mil

STUDENT FEEDBACK QUESTIONS

We value your suggestions, questions, and

criticisms on our courses. If you would like tocommunicate with us regarding this course, weencourage you, if possible, to use e-mail. If youwrite or fax, please use a copy of the StudentComment form that follows this page.

For subject matter questions:

E-mail: [email protected]: Comm: (850) 452-1501

DSN: 922-1501FAX: (850) 452-1370(Do not fax answer sheets.)

Address: COMMANDING OFFICERNETPDTC N3116490 SAUFLEY FIELD ROADPENSACOLA FL 32509-5237

For enrollment, shipping, grading, orcompletion letter questions

E-mail: [email protected]: Toll Free: 877-264-8583

Comm: (850) 452-1511/1181/1859

DSN: 922-1511/1181/1859FAX: (850) 452-1370(Do not fax answer sheets.)

Address: COMMANDING OFFICERNETPDTC N3316490 SAUFLEY FIELD ROADPENSACOLA FL 32559-5000

NAVAL RESERVE RETIREMENT CREDIT

If you are a member of the Naval Reserve,you may earn retirement points for successfully

completing this course, if authorized undercurrent directives governing retirement of NavalReserve personnel. For Naval Reserve retire-ment, this course is evaluated at 3 points. (Referto Administrative Procedures for Naval Reservists on Inactive Duty, BUPERSINST1001.39, for more information about retirementpoints.)


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Student Comments

Course Title: Information Systems Technician Training Series Module 4Communications Hardware

NAVEDTRA: 14225 Date :

We need some information about you :

Rate/Rank and Name: SSN: Command/Unit

Street Address: City: State/FPO: Zip

Your comments, suggestions, etc .:

Privacy Act Statement: Under authority of Title 5, USC 301, information regarding your military status isrequested in processing your comments and in preparing a reply. This information will not be divulged withoutwritten authorization to anyone other than those within DOD for official use in determining performance.

NETPDTC 1550/41 (Rev 4-00


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CHAPTER 1

COMMUNICATIONS HARDWARE

LEARNING OBJECTIVES

Upon completing this chapter, you should be able to do the following:

Determine the equipment required for each communications system.

Identify the hardware setup procedures for radio systems.

Identify the use of COMMSPOTS.

Identify procedures and requirements for communications equipment as it pertains to OTAR/OTAT functions.

Determine utilization, frequencies and watches needed for distress

communication equipment. Interpret how to monitor circuit quality equipment.

The high-paced operations required of modern fleetunits demand communication systems that are capableof providing high-speed, accurate, and securetransmission and reception of intelligence. To keeppace with the ever-increasing complexity of operations,

todays communication systems are necessarily highlysophisticated and versatile. For our ships andsubmarines to operate effectively, whetherindependently or as part of a battle group, they musthave communication systems and operators that arecapable of meeting this challenge.

In this chapter, we will discuss various aspects of fleet communication systems. As a Radioman, you willbe responsible for knowing the differentcommunication systems used by the Navy and whatcommunication equipments make up a system.

COMMUNICATIONS SYSTEMS

Through equipment design and installation, manyequipments are compatible with each other and can beused to accomplish various functions. Using this designconcept, nearly all the communication needs of a shipcan be met with fewer pieces of communicationsequipment than were previously required.

Communications can be maintained at the highestpossible state of readiness when all levels of commandunderstand the capabilities and limitations of thesystems. Many communications failures areattributable to poor administration rather than toequipment failure or technical problems.

In this section, we will discuss predeploymentreadiness; low-, high-, very-high-, ultra-high-, andsuper-high-frequency communications systems; andequipment components that comprise these systems.

UNDERWAY PREPARATION

Ships deploying to overseas areas must be in a stateof maximum operational and communicationsreadiness. Type commanders determine the level of readiness of deploying ships and ensure they areadequately prepared.

A check-off list is an excellent method to ensurethat step-by-step preparations are completed prior to adeployment. This list should cover all aspects of communications readiness and should begin well inadvance of the underway period. Some of the points tobe checked include scheduling of communicationsassistance team (CAT) visits, maintenance and

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operational checks of equipment and antennas, andconsumable supply levels.

The Basic Operational Communications Doctrine(U), NWP 4 (NWP 6-01), provides suggestedmin imum check-off shee t s , inc lud ing apredeployment check-off sheet and a preunderwaycheck-off sheet. The first sheet provides a timetable of required checks and objectives. The second sheet istailored to individual ships and unique requirements.

LOW-FREQUENCY SYSTEMS

The low-frequency (LF) band (30-300 kHz) is usedfor long-range direction finding, medium- and long-range communications, aeronautical radio navigation,and submarine communications.

A low-frequency transmitter, such as the AN/FRT-72, is used to transmit a high-powered signal overlongdistances. Low-frequency transmitters are normally

used only at shore stations or for special applications.The low-frequency receive system is designed to

receive low-frequency broadcast signals and toreproduce the transmitted intelligence. A typical low-

frequency receive system is shown in figure 1-1. Reto the equipments in the figure as you study the nesection.

1.

2.

3.

4.

Antennas The low-frequency signal isreceived by the antennas, which are connectto the receiver antenna patch panels andmulticouplers (AN/SRA-34, AN/SRA-57, AN/SRA-58). Multicouplers and patch paneallow the operator to select different antennand connect them to different receivers. Thway, an operator can select the correctcombination suited for a particular system.

LF Receiver The output of the receiver(audio) is fed to the receiver transferswitchboard.

Switchboard The switchboard can connethe receiver output to numerous pieces of equipment. In figure 1-1, the receiver output

connected to the AN/UCC-1 TeleprinterTerminal (discussed later).

AN/UCC-1 The AN/UCC-1, as a convertcomparator, converts the received audio sign

Figure 1-1.Low-frequency receive system.

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5.

6.

7.

(AF) to direct current (dc) for use by theteleprinter equipment.

Black dc Patch Panel The dc output of theAN/UCC-1 is fed to the SB-1203/UG DC PatchPanel. The dc patch panel permits the signal tobe patched to any cryptoequipment (discussedlater) desired.

Cryptoequipment The cryptoequipmentdecrypts the signal and connects its output to thered SB-1210/UGQ DC Patch Panel.

Red dc Patch Panel The SB-1210/UGQ canbe patched to a selected printer that prints thesignal in plain readable text.

HIGH-FREQUENCY SYSTEMS

The high-frequency (HF) band (3-30 MHz) is

primarily used by mobile and maritime units. Themilitary uses this band for long-range voice andteleprinter communications. This band is also used as abackup system for the satellite communications system.We will discuss satellite communications later in thischapter.

Figure 1-2 shows a typical high-frequency transmitsystem. In transmitting teleprinter information, theequipments shown in f igure 1-2 p erform the samefunctions as the equipments shown in figure 1-1, excepthe equipments in the high-frequency system do thefunctions in reverse order.

In the HF transmit system, the AN/UCC-1Telegraph Terminal converts dc signals into audio tonesignals. The output of the AN/UCC-1 is connected tothe transmitter transfer switchboard. The C-1004Transmit Keying and Receive Control/Teleprinter isused to key the transmitter during teleprinteroperations.

Voice communications from some remote locationsare also connected to the transmitter transferswitchboard. Voice communications are initiated at ahandset (remote phone unit) and connected to the C-1138 Radio Set Control. The output of the radio setcontrol is connected to the transmitter transferswitchboard. The transmitter transfer switchboardpermits the operator to select the proper transmitter forthe frequency to be transmitted.

Figure 1-2.High-frequency transmit system.

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Figure 1-3.High-frequency receive system.

Figure l-3 shows atypical high-frequency receivesystem. Refer to the figure as we follow the signal paththrough the system.

1 .

2 .

3 .

4 .

5 .

6 .

A transmitted high-frequency signal is receivedby the antenna, which converts electromagneticenergy to electrical energy.

The signal travels through a transmission line toan antenna patch panel, where it can bedistributed to any of a number of receivers.

The receiver converts the RF signal into ateleprinter or voice signal, depending upon whatis desired.

The output of the receiver is then sent to thereceiver transfer switchboard.

If a teleprinter signal was selected, theteleprinter signal from the switchboard goes tothe AN/UCC-1 and then follows the same pathas we described in the low-frequency receivesection. Identical pieces of equipment are used,and they perform the same functions.

If a voice signal was selected, the voice signalfrom the receiver transfer switchboard is sent tothe radio set control. The output is then sent to ahandset. The voice signal can also be sent fromthe switchboard to a remote speaker amplifier.There, it can be placed on a speaker so that the

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user can listen to the received signal withoutholding onto the handset.

VERY-HIGH-FREQUENCY SYSTEMS

The very-high-frequency (VHF) band (30-300MHz) is used for aeronautical radio navigation andcommunications, radar, amateur radio, and mobile

communications (such as for boat crews and landingparties). Figure 1-4 shows a basic block diagram of a

Figure 1-4.Very-high-frequency transmit and recesystem.


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VHF transmit and receive system using a transceiver.Although a transceiver is used in this system, thetransmit and receive systems are described separately.Refer to figure 1-4 as we follow the signal path on thetransmit side of the system.

On the transmit side of the system, the operator, at aremote location:

1.2.

3.

4.

5.

Talks into the handset.The handset is connected to the C-1138 RadioSet Control.

The output of the radio set control is sent to thetransmitter transfer switchboard.

The output of the switchboard is sent to thetransmit side of the transceiver.

The transceiver converts the input signal to anRF signal for radiation by the antenna.

Continue to refer to figure 1-4 as we follow the path of the incoming signal.

1.

2.

3.

4.

5.

The incoming signal in figure 1-4is received bythe antenna.

This signal is sent to the receive side of thetransceiver.

The output of the transceiver is sent to thereceiver transfer switchboard.

From the receiver transfer switchboard, theoutput is sent to either the C-1138 Radio SetControl or to a speaker amplifier, or both,depending on the preference of the user.

The output of the radio set control is sent to ahandset.

6. A speaker receives the output of the speakeramplifier.

ULTRA-HIGH-FREQUENCY SYSTEMS

The ultra-high-frequency (UHF) band (300-MHzto 3-GHz) is used for line-of-sight (short-range)communications. The term line of sight, as used incommunications, means that both transmitting and

receiving antennas must be within sight of each otherand unaffected by the curvature of the Earth for propercommunications operation.

The UHF band is also used for satellitecommunications. Although satellite communicationsare line of sight, the distance the signal travels is muchgreater than that of UHF surface communications,because the antennas remain in sight of each other.

As in the VHF section, the transmit and receivesystems will be described separately. Figure 1-5 showsa basic block diagram of a UHF transmit system, whicuses a transceiver.

1.

2.

3.

4.

On the transmit side of the nonsecure voicesystem, the operator at a remote location talksinto the handset. The handset is connected to thC-1138 Radio Set Control.

The C-1138 is connected to the transmittertransfer switchboard, where it is patched to thetransmitter.

The operator at a remote location talks into thesecure voice remote phone unit (RPU).

The RPU is connected to the secure voicematrix. This is the tie point for connecting morthan one RPU. The output of the matrix is

Figure 1-5.Ultra-high-frequency transmit system.

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5.

6.

7.

connected to the secure voice equipment, whichencrypts the information received.

The output of the secure voice equipment isconnected to the transmitter transferswitchboard.

The transmitter transfer switchboard is used toconnect numerous RPUs to any number of transmitters.

The output of the patch panel is connected to thetransmitter side of the transceiver, which, inturn, is connected to an antenna coupler.

Figure 1-6shows a basic diagram of a UHF receivesystem. We will next follow the UHF signal paththrough the receive side of the system.

1.

2.

3.

4.

5.

The received signal is picked up by the antennaand connected to the receiver side of thetransceiver through the antenna coupler.

The output of the receiver is connected to thereceiver transfer switchboard. From here, it can

be connected to either the nonsecure or thesecure voice systems, depending upon the modeof transmission.

When a nonsecure signal is received, the outputof the receiver transfer switchboard can beconnected to the radio set control or a speakeramplifier, or both, depending on the preferenceof the user.

The output of the radio set control is connectedto a handset, whereas the output of the speakeramplifier is connected to a speaker.

If a secure voice transmission is received, theoutput of the receiver transfer switchboard is

6.

7.

connected to the secure voice equipment, wit is decrypted.

The secure voice equipment output is conneto the secure voice matrix. The secure voicematrix performs the same function as the mon the transmit system.

The secure voice matrix output is connected tothe secure remote phone unit. Here, the signconverted back to its original form.

SUPER-HIGH-FREQUENCY SYSTEMS

The super-high-frequency (SHF) band (3-30 GHz)is strictly for line-of-sight communications. It isconfigured much the same as the UHF system. SHF ismainly used for satellite communications.

SHF satellite communications is a high-volumesystem that offers reliable tactical and strategiccommunications services to U.S. Navy elements aand afloat. The system is composed of the terminal

segment, consisting of U.S. Navy-operated Earthterminals and mobile terminals. It also includes aportion of the Defense Satellite CommunicationsSystem (DSCS) satellite segment. Navy Super HigFrequency Satellite Communications, NTP 2, Sectio1 (C), provides comprehensive coverage of the NavySHF satellite system.

PATCH PANELS

Teleprinter patch panels are used for theinterconnection and transfer of teleprinter signals

aboard ship. In the previous block diagrams two patchpanels, one labeled red, the other black, were shownThese are the teleprinter patch panels SB-1210/UG

Figure 1-6.Ultra-high-frequency receive system.

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SB-1203/UGQ (figure 1-7) . The SB-1210/UG isintended for use with cryptographic devices; the SB-1203/UGQ is a general-purpose panel.

The patch panels are red or black to identify secureand nonsecure information. Red indicates that secure(classified) information is being passed through thepanel. Black indicates that nonsecure (unclassified)information is being passed through the panel.

Both panels are also labeled with signs. The redpanel sign has 1-inch-high white block letters that readRED PATCH PANEL. The black panel normally hastwo black signs containing l-inch-high white block letters. One sign reads BLACK PATCH PANEL andthe other, UNCLAS ONLY.

Each panel contains six channels. Each channel haits own series circuit of looping jacks, set jacks, and arheostat for adjusting line current. The number of looping and set jacks in each channel varies with thepanel model. Each panel includes a meter and rotaryselector switch for measuring the line current in anychannel.

Six miscellaneous jacks are contained in eachpanel. Any teleprinter equipment not regularlyassigned to a channel maybe connected to one of these

jacks. In some instances, commonly used combinationof equipment are permanently wired together within thpanel (called normal-through).

Figure 1-7.Teleprinter patch panels.

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CRYPTOGRAPHIC EQUIPMENT

Some of the systems in the previous figurescontained cryptographic equipment. Cryptographicequipment is only one of a number of the elements thatmake up a secure communications system. Thoughseveral different types of on-line cryptoequipments arein use throughout the naval communications system,they are all designed to perform the same basic function:

to encipher and decipher teleprinter or digital datasignals.

Simply stated, the transmitter accepts a plain textteleprinter or data signal containing classified materialfrom the classified patch panel (red). It then adds akey, and relays the sum as cipher text, or anenciphered signal. A key is a sequence of randombinary bits used to initially set and periodically changepermutations in cryptoequipment for decryptingelectronic signals.

Following this encryption, the signal is fed to theunclassified patch panel (black). Here, it is patcheddirectly to the frequency-shift keyer or the multiplexequipment of the transmitter and converted into anaudio signal. The audio signal, now in a form suitablefor transmission, is routed to the transmitter via thetransmitter transfer switchboard.

On the receive side, the signal flow is quite similarto the send side in reverse order. The receiver acceptsthe enciphered signal from the black patch panel andgenerates a key to match the one generated by thetransmitter. The receiver then subtracts the key from thecipher text input (which restores the plaintextteleprinter or data signal). Finally, it passes the signalon to the red patch panel for dissemination to theterminal equipment for printout.

For further information and operator instructionson a specific type of cryptoequipment, refer to theapplicable KAO publication.

AN/UCC-1 TELEGRAPH MULTIPLEXTERMINAL

Because of the traffic volume handled, many shipsand shore stations require multiple teleprinter circuitson one sideband circuit. The method for increasingcircuits on a sideband is calledmultiplexing. The Navyuses two multiplexing techniques in communications:time division and frequency division. The AN/UCC-1Telegraph Multiplex Terminal uses the frequency-division technique.

The AN/UCC-1 Telegraph Multiplex Terminal(figure 1-8) is a frequency-division multiplexedterminal equipment for use with single-sideband (SSB)or double-sideband (DSB) radio circuits, audio-frequency wire lines, or microwave circuits. TheAN/UCC-1 is normally used afloat on a multichannelship-shore full-period termination (discussed later).

The following is an overview of how the AN/ UCC-1 works:

At the transmitting station, the signals from theindividual circuits, known as channels, aremultiplexed into one composite signal fortransmission. The transmission with themultiplexed channels is known as a tone

package.

At the receiving station, the composite signal(tone package) is demultiplexed (separated) individual signals and distributed to separateteleprinters, as required.

The terminal can operate in a nondiversity, audio-frequency diversity, space diversity, or radio-frequdiversity mode. Because of this versatility, the termis installed in various configurations throughout theNavy.

Each electrical equipment cabinet houses onecontrol attenuator (right side) and up to a maximum ofeight frequency-shift keyers or eight frequency-shiftconverters.

Since the control attenuator, keyers, and conveare solid-state, integrated-circuit, plug-in modules, thenumber of channels can be varied by increasing ordecreasing the total number of modules. Dependingupon the number of modules and the configurationused, the terminal can provide up to 16 narrowbandchannels.

For example, if the terminal has keyers in the topcabinet and converters in the bottom cabinet, the sycould transmit different information on eight channels.Each keyer would represent a channel on the transmitside and each converter, a channel on the receive side.

Each frequency-shift keyer accepts a dc telegraphsignal input from an external loop and generates theappropriate audio-frequency mark and spacefrequency-shift output. The individual keyers eachcontain two oscillators operating on opposite sides of acenter frequency. For example, in figure 1-9, the centfrequency of keyer number one is 425 Hz, the markfrequency is 382.5 Hz, and the space frequency is 4

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Figure 1-9.Keying frequencies of the AN/UCC-1.

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Hz. These audio-frequency mark and space outputs arereferred to as tones; thus keyer one has a one-channel,two-tone output.

A dc telegraph signal on channel 1 determineswhich frequency is gated from the keyer to the groupattenuator. Each channel works in the same way. Itaccepts a dc signal of marks and spaces from selectedequipments patched to that channel. It then provides anaudio output of either a mark or space frequency-shifted

tone, according to the input.The individual tones are combined at the control

attenuator into a composite tone package. The controlattenuator ensures that the composite tones remain at aconstant amplitude for modulating the transmitter.

At the receiving end of the communications link,the AN/UCC-1 reverses the process performed at thetransmitting end. The AN/UCC-1 applies theinformation on each of the channels to the selectedequipments connected to the converter of that charnel.

In a frequency-division circuit configuration, eachchannel has an input from a different teleprinter. If achannel fades at a particular frequency, the informationon the channel could be lost or distorted. In such cases,the information may need to be retransmitted. To helpprevent this, diversity switches that will permit the useof more than one channel for the same intelligence areavailable.

In switch position 1, only the normal channel isused. In position 2, a single teleprinter signal providesinput for two adjoining keyers. In position 4, four

keyers are connected to the same input loop. Theswitches on all keyers must be in the same position toprovide the same intelligence to the selectedcombination of channels.

When identical intelligence untransmitted on two orfour channels, it is less likely to be lost or distorted. Atthe receiving end, two or four corresponding convertersmay be used; the converter having the stronger signal

input automatically provides the signal to be used byreceiving teleprinter.

In the fleet broadcast multiplexing system, whichconsists of 16 channels, 2 channels normally carry thesame intelligence. This process is called twinning.

Another method of multiplexing mentioned earlieris time-division multiplexing (TDM). In this method, adigital input is fed to a TDM unit. Here, it ismultiplexed into a composite intelligence stream fortransmission. The output is sent to an end user, wheis broken into its original individual inputs.

However, instead of splitting the frequencies as infrequency-division multiplexing (FDM), TDM sharestime. Each input uses the full bandwidth of the assigfrequency but is assigned unique time portions of thesystem. Figure 1-10 illustrates the front panel of a full-duplex time-diversity modem.

SHIP-SHORE CIRCUITS

As we mentioned earlier, the fleet broadcast is theprimary means for delivering messages to afloatcommands. This section discusses a few of the othertypes of circuits by which a ship can transmit itsmessage traffic ashore or to other ships for delivery orrelay.

SHIP-SHORE CIRCUIT MODES OFOPERATION

There are three methods of operatingcommunications circuits: duplex, simplex, and

semiduplex. The mode of operation at any given timedepends upon equipment and frequency availability.

Duplex

Duplex describes a communications circuitdesigned to transmit and receive simultaneously. Insuch operations, each station transmits on a differentfrequency and both stations transmit concurrently. B

Figure 1-10.Full-duplex time-diversity modem.

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stations are required to keep transmitters on the air at alltimes and to send a phasing signal at the request of thedistant end. Figure 1-11 shows a diagram of a UHF/HFfull-duplex FSK (frequency-shift keying) single-channel teleprinter relay circuit.

There are two types of duplex operation: fullduplex and half duplex. Full duplex (FDX) refers to acommunications system or equipment capable of transmitting simultaneously in two directions. Half duplex (HDX) pertains to a transmission over a circuitcapable of transmitting in either direction, but only onedirection at a time.

Small ships traveling in company normally useduplex in a task group common net in which theyterminate with a larger ship that is serving as net control.The net control ship provides the ship-shore relayservices. Ships traveling independently can use this

system for anon-call ship-shore termination to transmittheir outgoing messages.

Simplex

Simplex is a method of operation that provides asingle channel or frequency on which information canbe exchanged (figure 1-12). Simplex communicationsoperation is normally reserved for UHF and those shipthat do not have sufficient equipment for duplexoperation. In some cases, a simplex circuit can beestablished when equipment casualties occur.

Where no HF simplex frequency is indicated orguarded, ships requiring a simplex ship-shore circuitmust call on a duplex ship send frequency. The shipmust state SIMPLEX in the call-up, indicating thatthe ship cannot transmit and receive simultaneously.

Figure 1-11.UHF/HF full-duplex FSK single-channelteleprinter relay circuit.

Figure 1-12.UHF/HF netted simplex FSK teleprinter relacircuit.

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When a ship requests simplex operation on duplexcircuits, the shore station may be required to shifttransmitters prior to acknowledging call-up. If no replyis received within 45 seconds, the ship should repeat thecall-up procedures. If a third attempt is required, theship should check equipment to ensure properoperation.

Semiduplex

Semiduplex communications circuits, usedprimarily on task force/task group/ORESTES, are acombination of the simplex and duplex modes. Allstations except the net control station (NECOS)transmit and receive on the same frequency. TheNECOS transmits and is received on a secondfrequency. The NECOS may transmit continuously,whereas all other stations must transmit in accordancewith simplex procedures.

UHF/HF RELAY

The UHF/HF relay method permits long-range,uninterrupted communications during periods of hazardous electromagnetic radiation (HERO). Figur1-13 shows a block diagram of a UHF/HF voice relaycircuit.

Modern radio and radar transmitting equipmentsproduce high-intensity RF fields. It is possible for RF

energy to enter an ordnance item through a hole or cin its skin or to be conducted into it by firing leads,wires, and the like. Here is an example of HERO. Anaircraft carrier is arming aircraft on board. Duringarming operations, all HF transmitters must be securedto prevent possible detonation of the ordnance. Tomaintain its ship-shore communications, the carriertransmits to a relay ship via a UHF circuit. The relaship then retransmits the signal on a HF circuit to at e rmina ted NAVCOMTELSTA. On- l ine

Figure 1-13.UHF/HF voice relay circuit.

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radioteleprinters can be relayed, as well as voice, usingthis circuit.

SECURE VOICE WORLDWIDE VOICENETWORK

The secure voice network is designed to providered-time voice communications between forces afloatand operational commanders ashore, using either HF orsatellite connectivity. This system is commonlyreferred to as GPS Worldwide HICOMM.

System Control

This system consists of three separate networks.Each network has an area control station controlled by aFLTCINC; either CINCLANTFLT, CINCPACFLT, orCINCUSNAVEUR. Each area has subarea controlstations determined by each FLTCINC to ensureworldwide coverage.

Satellite System Control

The secure voice system, using satellitetransmissions, has limited shore access points at thefour COMMAREA mas te r s t a t ions andNAVCOMTELSTA Stockton, California. These sitesserve as the interface channel to both the wideband andnarrowband voice systems in order to extend calls tooperational commanders ashore.

Net Membership

If a ship, aircraft, or shore station needs to enter thesecure voice network, it must be prepared to do so with

minimum time delay. Units desiring to enter the net on atemporary basis must specify the length of time andpurpose for entering the net. They must also obtainpermission from the appropriate control station. Thearea net control station (NECOS) is responsible forcompleting all calls originating from senior commandsto all commands, ships, or aircraft within the specificFLTCINCs net. Certain rules must be observed whenon the secure voice net, as follows:

HF transmitter tuning is prohibited on securevoice. Transmitters must be calibrated and

pretuned on a dummy load. Final tuning may beaccomplished during live transmissions.

All stations must maintain a continuous log onsecure voice. The actual time of significanttransmissions must be entered into the log.When available, recording devices must be usedin lieu of a paper log.

The net operates as a free net unless otherwisedirected by the area FLTCINC. NECOS retainsthe prerogative of exercising control over alltransmissions to ensure proper circuit discipline

FULL-PERIOD TERMINATIONS

Full-period terminations are dedicated circuits thatprovide communications between shore stations andafloat commands. These terminations requireallocation of limited NCTAMS/NCTS assets.Therefore, the criteria for requesting, approving, andestablishing such circuits is necessarily strict.

Termination Requests

Afloat commands and individual units can requestfull-period termination during special operations,deployments, intensive training periods, or exerciseswhen primary ship-shore circuits will not suffice.Commands should request full-period terminationsonly when traffic volume exceeds speed and capabilityof ship-shore circuits and when operational sensitivityrequires circuit discreetness or effective command andcontrol necessitates dedicated circuits.

T h e h e a v y d e m a n d s p l a c e d u p o nNCTAMS/NCTSs for full-period terminations requiremaximum cooperation between shore stations andafloat commanders prior to and during an operation.Ships having a need for a full-period termination, eithefor training or operational requirements, must submit atermination request to the COMMAREA master statioat least 48 hours prior to activation time.

Emergency commitments or a command directivemay necessitate a lead time of less than 48 hours.Whenever possible, however, the 2-day limit must behonored to achieve maximum preparation andcoordination. NTP 4 gives details of requiredinformation that must be included in a terminationrequest message.

The COMMAREA master station will assign ashore station for a ships termination circuit. Once theshore station has been assigned, both the ship and thestation may begin coordination to identify specificequipment keylists and frequencies needed to effecttermination. The shore station will also act as NECOS.Two hours prior to the scheduled termination, the shorstation can coordinate with the ship by telephone, locacircuitry, or by primary ship-shore.

When the ship shifts terminations, the securing of the current termination and the establishment of a new

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termination should coincide with a broadcast shiftwhenever possible. The ship must submit aCOMMSHIFT message.

Termination Types

There are six types of full-period terminations, asfollows:

Single-channel radioteleprinter using eitherradio path or landline transmission media;

Single-channel low-data-rate satellite accessusing satellite transmission media;

CUDIXS special satellite access forNAVMACS-equipped ships using satellitetransmission media;

Multichannel radioteleprinter using either radiopath or landline transmission media;

Multichannel radioteleprinter using SHFsatellite transmission media; and

Tactical intelligence (TACINTEL) access forTACINTEL-equipped ships using satellitetransmission media.

Equipment Tests

To ensure that circuit equipment is in peak operational condition, complete system back-to-back off-the-air tests must be completed 24 hours prior totermination activations. Check cryptoequipment back-

to-back after daily crypto changes and prior to puttingcircuits into service.

An aggressive PMS and quality monitoringprogram is essential. When checking equipment, look for power levels, scorch or burn marks, properoperation of interlocks, and cleanliness. When cleaningand inspecting antennas, look for cracks, chips, orblistering of insulators. Also check for deterioration,loose connectors, and correct insulator resistance.

COMMSPOT Reports

COMMSPOT reports will be submitted by allships, including nonterminated units, any time unusualcommunication difficulties are encountered. Ships willsubmit the COMMSPOT to the terminatingcommunications station. Timely submission of COMMSPOT reports is necessary to minimize furtherdeterioration of the situation.

Rules and general instructions for preparingJINTACCS formatted COMMSPOT reports are foundin the Joint Reporting System (General Purpose Re

ports), NWP 1-03, Supp-1 (formerly NWP 10-1-13).

PRIMARY SHIP-SHORE CIRCUITS

Primary ship-shore (PRI S/S) circuits are encryFSK/PSK teleprinter nets that permit ships to transmit

messages for delivery ashore. This service is availableto units that do not maintain a full-period ship-shoretermination. Navy tactical UHF satellites or theHF/UHF spectrum may be used to conduct ship-shorecircuit operations. Ships may use this circuit forcoordinating and establishing a full-period terminationwith the shore station.

T h e f r e q u e n c i e s f o r N C TA M S a n dNAVCOMTELSTAS that guard primary fleet ship-shore circuits are listed in applicable CIBs distributedby the COMMAREA master stations. Thesefrequencies are subject to change by the cognizantFLTCINC or by the NCTAMS.

OVER-THE-AIR TRANSFER (OTAT) ANDOVER-THE-AIR REKEY (OTAR)

There are significant vulnerabilities associatedthe handling of paper cryptographic material. Soundapplication of over-the-air transfer/rekey(OTAT/OTAR) procedures and techniques can reducethe amount of paper keying material required andreduce the potential for compromise. These proceduresand techniques are contained in the NAG-16BProcedures Manual for Over-the-Air Transfer (OTATand Over-the-Air Rekey (OTAR).

OTAT/OTAR also makes the transfer of keyingmaterial more responsive to rapidly changingoperational requirements. The use of NAG-16B wadeveloped and verified by extensive use duringoperation Desert Shield/Storm. The specifiedprocedures served as an effective vehicle fortransferring keying to satisfy rapidly changing joinNavy requirements. Expanded definitions, generalprocedures, and equipments are found in NAG-16B.

DISTRESS COMMUNICATIONS

Special methods of communication have beendeveloped to use in times of distress and to promotsafety at sea and in the air. Distress message traffic isbest described as all communications relating to thimmediate assistance required by a mobile station i

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distress. Distress traffic has priority over all othertraffic. All U.S. Navy communicators must be familiarwith distress signals to properly evaluate their meaningsand to take appropriate action when necessary.

If a ship becomes involved in a distress situation,communications personnel should send distressmessages on normal operating encrypted circuits. If theneed for assistance outweighs security considerations,the ships commanding officer may authorize thetransmission of an unclassified distress message on oneof the national or international distress frequencies.

When a ship in distress is traveling in company withother ships, the ship in distress will transmit the distressmessage to the officer in tactical command (OTC), whowill take appropriate action.

DISTRESS FREQUENCIES

Several frequencies in different bands aredesignated for the transmission of distress, urgency,safety, or search and rescue (SAR) messages. The

following frequencies have been designated for useduring a distress or emergency situation:

500 kHz International CW/MCW distress andcalling;

2182 kHz International voice distress, safety,and calling;

8364 kHz International CW/MCW lifeboat,life raft, and survival craft;

121.5 MHz International voice aeronautical

emergency;156.8 MHz FM United States voice distressand international voice safety and calling; and

243.0 MHz Joint/combined military voiceaeronautical emergency and internationalsurvival craft.

During SAR missions, the following frequenciesare authorized for use:

3023.5 and 5680 kHz International SARfrequencies for the use of all mobile units at thescene of a search. Also for use of shore stationscommunicating with aircraft proceeding to orfrom the scene of the search. CW and voice areauthorized.

123.1 MHz International worldwide voiceSAR use.

138.78 MHz U.S. military voice SAR on-the-scene use. This frequency is also used fordirection finding (DF).

172.5 MHz U.S. Navy emergency sonobouycommunications and homing use. Thisfrequency is monitored by all U.S. Navy ASWaircraft assigned to a SAR mission.

282.8 MHz Joint/combined on-the-scene

voice and DF frequency used throughout NATO.The control of distress message traffic on any

designated frequency is the responsibility of the stationin distress. However, this station may delegate itsresponsibility to another station on the frequency.

Distress Watches

Navy units at sea have always maintained listeningwatches on distress frequencies. Communicationwatch requirements vary according to the operationalmission of the ship and available equipment assets.

Ships in company normally divide distress watchrequirements among the group.

STATUS BOARD

The technical control of the shore station that isNECOS for fill-period terminations and PRI S/Scircuits must maintain a status board. The status boardshould indicate, as a minimum, all systems/circuits thaare active, tuned in, or in a standby status. It should alsoindicate all inoperative equipment. The watchsupervisors must verify the accuracy of the information

contained on the status board at watch turnover andupdate while on watch. The status board must show thefollowing minimum information for active and standbycircuits:

Functional title of circuit;

Frequency(ies), both send/receive, if fill-duplexoperation is used;

Circuit designator, from communication plan;

Transmitter and receiver designations;

For shore stations, keying line designations;

Terminal equipment designation (for example,R-2368/URR #l);

Cryptoequipment, keying material, and restarttime;

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Figure 1-14.AN/SSQ-88 Quality Monitoring Set and RCS interface.

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Figure 1-15.AN/SSQ-88 equipment configuration.

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Operating position or remote control unitdesignation; and

Remarks, as appropriate.

QUALITY MONITORING

In recent years, the volume of communications has

increased dramatically. This rapid expansion has led tothe installation of increasingly sophisticatedequipment. Such factors as frequency accuracy, dcdistortion, inter-modulation distortion (IMD), anddistribution levels are critical to the operation of communications systems.

Satisfactory operation of these systems demandsprecise initial line-up and subsequent monitoring.System degradation is often caused by many smallcontributing factors that, when combined, render thesystem unusable. Simply looking at the page printer orlistening to the signal is inadequate.

Simply stated, quality monitoring is theperformance of scheduled, logical checks that willensure continuous, optimum performance and, in manycases, prevent outages before they occur. Somecommunications personnel quite often fail to realize thebenefits of quality monitoring. An attitude developsthat questions the need for quality monitoring. Theresult of this incorrect attitude is that circuits are eitherUP or DOWN. Personnel with this attitude perform noquality monitoring when the circuits are UP and are,therefore, forced to treat each outage as if it were a

unique occurrence.With no precise information concerning the trend of

the systems performance, personnel must jump fromone assumed probable cause to another assumedprobable cause, while valuable circuit time is lost. Aship with an aggressive quality monitoring programusually has personnel who are thoroughly familiar withall installed communications systems.

QUALITY MONITORING PROGRAM

The primary function of the quality monitoringprogram is the direct measurement of signal qualitycharacteristics, including:

Dc distortion;

Audio distribution level;

Frequency accuracy of RF signals;

Spectrum analysis; and

Loop current.

These measurements are broad categories and can bbroken down to specific tests for specific systems.

Quality Monitoring System

Figure 1-14 is a diagram of a quality monitorinsystem and RCS interface. The system was desigprovide a means of monitoring and evaluatingperformance of any communications system used bforces afloat.

The monitoring system is a grouping of specifequipments into a console designated as the AN/SSQ88 Quality Monitoring Set. The set contains equifor measuring and analyzing signals sampled by sinstalled in each communications circuit interface. Thsystem should be operated only by personnel withsufficient knowledge to analyze the signals beingtransmitted and received via the ships circuits,including individual channels of the multichannelcircuits.

The console configuration shown in figure 1-1may not be compatible with all ships; however, moships can use equivalent test equipment to establishquality monitoring test system.

SUMMARY

Your commanding officer must be able tocommunicate with ships and shore stations to maintaeffective command and control of the situation at

Communications are, and always will be, the voice command. In the age of nuclear weapons, guidedmissiles, supersonic aircraft, and high-speed ships ansubmarines, top performance is required of our fleecommunicators. You, as a Radioman, and yourequipment must always be in constant readiness tothis formidable challenge.

Distress communications are methods that havbeen developed for use in times of distress. Theyindicate the need for immediate assistance and havpriority over all other traffic. Various publications an

local instructions will assist you in carrying out yourequired responses to these situations.

Communication systems are periodically tested tensure that they operate efficiently and accuratelycombined tests, checks, and measurements helpdetermine the condition of systems, subsystems, anindividual equipments. Tests and measurements of communication systems and equipments range frovery simple to the very complex.

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Figure 2-1.OE-82C/WSC-1(V) antenna group.

Figure 2-2.AS-2815/SSR-1 antenna physical configuration.

The AN/SRR-1 receiver system consists of up four AS-2815/SSR- 1 antennas (figure 2-2) with amplifier-converter, AM-6534/SSR-1, for eachantenna. The antennas are used to receive satellitbroadcasts at frequencies of 240 to 315 MHz. Theantenna and converters are mounted above deck at least one antenna is always in view of the satellite

The newer satellite systems use the SHF bandof the major advantages of these systems is that tha very small parabolic antenna measuring only 12inches in diameter.

A satellite antenna must be pointed at the satelcommunicate. We must first determine the azimut(AZ) and elevation (EL) angles from a fixed locatioFigure 2-3 illustrates how these angles are derive

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using a pointing guide called the Equatorial SatelliteAntenna Pointing Guide. This guide is normallyavailable through the Navy Supply System.

The antenna pointing guide is a clear plasticoverlay, which slides across a stationary map. Itindicates AZ and EL angles in degrees to the satellite.The values obtained are useful to the operator in settingup the antenna control unit of a satellite system.

To use the guide, follow these procedures:Center the overlay directly over the desiredsatellite position on the stationary map.

Mark the latitude and longitude of the ship on theplastic antenna pointing guide with a greasepencil.

Determine the approximate azimuth angle fromthe ship to the satellite.

Locate the closest dotted line radiating outward

from the center of the graph on the overlay inrelation to the grease dot representing the ships

location. This dotted line represents degrees of azimuth as printed on the end of the line. Someapproximation will be required for ship positionsnot falling on the dotted line.

Determine the degrees of elevation by locatingthe solid concentric line closest to the shipsmarked position. Again, approximation will berequired for positions not falling directly on thesolid elevation line. Degrees of elevation aremarked on each concentric line.Example: Assume that your ship is located at30 north and 70 west. You want to accessFLTSAT 8 at 23 west. When we apply theprocedures discussed above, we can see theexample indicates an azimuth value of 115 andan elevation angle of 30.

TYPES OF SATELLITES

Three types of communications satellites are in use

by the U.S. Navy today. They are GAPFILLER, FleetSatellite Communication (FLTSATCOM), and Leased

Figure 2-3.Equatorial Satellite Antenna Pointing Guide.

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Satellite (LEASAT) (figure 2-4). These satellites are ingeosynchronous orbit over the continental UnitedStates and the Atlantic, Pacific, and Indian oceans.Each satellite is described in the following paragraphs.

GAPFILLER

In 1976, three satellites, called MARISAT, wereplaced into orbit over the Atlantic, Pacific, and Indianoceans. Each satellite had three UHF channels formilitary use, one wideband 500-kHz channel, and twonarrowband 25-kHz channels.

The Navy leased the UHF section of each satellitefor communications purposes. To distinguish thespecial management and control functions for

communications on these UHF channels, the Navthe name GAPFILLER to the leased satellite assets.

GAPFILLER was intended to fill the need focontinuing satellite communications capability insupport of naval tactical operations until the Navyachieved a fully operable Fleet SatelliteCommunications (FLTSATCOM) system.

The GAPFILLER satellite over the Indian Octhe only one still being used by the U.S. Navy. Thtwo GAPFILLER satellites were replaced by LEThe active GAPFILLER satellite will also be replacby LEASAT as it reaches the end of its operationa

Within the 500-kHz band, transponders provide individual 25-kHz low- and high-data-ratecommunications channels for 75 baud ship-shore

Figure 2-4.GAPFILLER, FLTSATCOM, and LEASAT satellites.

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communications and for the automated informationexchange systems. The UHF receiver separates thereceive band (302 to 312 MHz) from the transmit band(248 to 258 MHz).

The receiver translates the received carriers tointermediate frequencies (IFs) in the 20-MHz range andseparates them into one of three channels. One charnelhas a 500-kHz bandwidth, and two have a bandwidth of

25 kHz each. The signals are filtered, hard limited,amplified to an intermediate level, and up-converted tothe transmit frequency. Each channel is then amplifiedby one of three high-power transmitters.

GAPFILLER also supports the FLTSATCOMsystem secure voice system and the fleet broadcast inthe UHF range. The GAPFILLER communicationssubsystem will eventually be replaced by theFLTSATCOM system.

FLTSATCOM

There are four FLTSATCOM satellites in service.These satellites are positioned at 100 W, 72.5 E, 23W, and 172 E longitudes. They serve the Third, Sixth,Second, and Seventh fleets and the Indian Ocean battlegroups. These four satellites provide worldwide

coverage between 70 N and 70 S latitudes (figure2-5).

Each FLTSATCOM satellite has a 23-RF-channelcapability. These include 10 25-kHz channels, 12 5-kHz channels, and 1 500-kHz channel. The 500-kHzand the 10 25-kHz channels are reserved for Navy use.Of the 10 25-kHz channels, channel 1 is used for thefleet broadcast. All charnels use SHF for the uplink transmission. SHF is translated to UHF for thedownlink transmission.

There is a separate UHF downlink transmitter foreach channel. Each of the 23 channels has 3 differentfrequency plans in which the uplink or downlink may betransmitted. This capability precludes interferencewhere satellite coverage overlaps.

LEASAT

The latest generation of Navy communications

satellites is leased; hence, the program name LEASAT.As we mentioned earlier, these satellites replaced 2 of the 3 GAPFILLER satellites and augment theFLTSATCOM satellites.

CONUS LEASAT (L-3) is positioned at 105 Wlongitude, LANT LEASAT (L-1) is positioned at

Figure 2-5.FLTSATCOM coverage areas,

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15 W longitude, and 10 LEASAT (L-2) is positionedat 72.5 E longitude (figure 2-6).

Each LEASAT provides 13 communicationschannels using 9 transmitters. There are 7 25-kHz UHFdownlink channels, 1 500-kHz wideband channel, and5 5-kHz channels. The 500-kHz channel and the 725-kHz channels are leased by the Navy. One of the 725-

kHz UHF downlink channels is the downlink for theFleet Satellite Broadcast.

The broadcast uplink is SHF, with translation toUHF taking place in the satellite. The remaining 625-kHz channels function as direct-relay channels withseveral repeaters. Currently, the LEASAT channelsprovide for the following subsystems:

Channel 1 for Fleet Satellite Broadcasttransmissions;

1 25-kHz channel for SSIXS communications;

1 25-kHz channel for ASWIXS com-munications; and

2 25-kHz channels for subsystems that transmor receive via DAMA (Demand AssignedM u l t i p l e A c c e s s ) ( f o r e x a m p l e ,CUDIXS/NAVMACS, TACINTEL, and securvoice).

PHASE IV

Operations Desert Shield/Desert Storm reinforcthe requirement for and greatly accelerated theintroduction of SHF SATCOM capability on aircracarriers and amphibious flagships to satisfy minimutactical command and control (C2), intelligence anwarfighting communications requirements whileimproving Joint and NATO/Allied communicationinteroperability. To meet the urgent operationalrequirement, the U.S. Navy obtained and modifieAir Force AN/TSC-93B Ground Mobile Forces (GMFSHF SATCOM vans for installation on aircraft carrierand amphibious flagships deploying to the Persian

Gulf. The modified vans were coupled with theAN/WSC-6(V) standard U.S. Navy SHF stabilizedantenna system, the SURTASS modem, 2 low speetime division multiplexer (LSTDMs), and addition

Figure 2-6.LEASAT coverage areas.

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Figure 2-7.Satellite communications systems.

Wide operating bandwidth permits highinformation transfer rates and facilitates spreadspectrum modulation techniques. Spread spectrummodulation is a particularly valuable technique forlessening the effects of enemy jamming. Althoughwide bandwidth permits both high information transferrates and AJ capabilities when using the OM-55(V)/USC modem, it may not permit bothsimultaneously in the presence of jamming. Therefore,high information transfer rates will be significantlyreduced when jamming is encountered, permitting only

certain predetermined critical circuits to be maintained.Narrow uplink transmission beamwidth provides a

low probability of intercept (LPI) capability. An uplinkLPI capability reduces the threat of detection andsubsequent location, but does not in and of itself denyenemy exploitation of those communications if detection is achieved. SHF frequencies are rarelyaffected by naturally occurring scintillation, making

SHF SATCOM a particularly reliable form of communications.

A characteristic of SHF, favorable to flagshipsthe ability to communicate critical C4I for the userinformation in the presence of enemy jamming adue regard for enemy detection capabilities. SUMilitary Sealift Command Auxiliary General OceSurveillance (T-AGOS) ships were initially equippwith SHF SATCOM, taking advantage of the highinformation transfer rate capability and LPIcharacteristics. Because of larger available bandinherent jam-resistance, and increasing demands limited tactical UHF SATCOM resources, additioapplications for DSCS SHF SATCOM afloat arecontinually being investigated for the Fleet.

The radio group consists of a high power ampli(HPA) or medium power amplifier (MPA), low noamplifier (LNA), up-converter, down-converter, afrequency standard. For transmit operations, theup-converter translates the modems 70 or 700

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Figure 2-8.AN/SSR-1 receiver system.

megahertz (MHz) intermediate frequency (IF) to thedesired radio frequency. The signal is then passed to theHPA or MPA and amplified to its authorized powerlevel. During receive operations, the LNA amplifies thereceived RF signal and sends it to the tracking converter

for antenna control and the down-converter fortranslation to 70 or 700 MHz IF. This signal is then sento the modem for conversion to digital data. Systemfrequency stability is provided by a cesium or rubidiumstandard.

FLEET BROADCAST SUBSYSTEMEQUIPMENT

The SATCOM equipments that the Navy uses for

the fleet broadcast include the SATCOM broadcastreceiver (AN/SSR-1), the FLTSATCOM SHFbroadcast transmitter (AN/FSC-79), the standardshipboard transceiver (AN/WSC-3), the shore stationtransceiver (AN/WSC-5), and the basic airbornetransceiver (AN/ARC-143B). A brief description of these equipments is given in the next paragraphs.

The AN/SSR-1 is the Navys standard SATCOMbroadcast receiver system. This system consists of up tofour AS-2815/SSR-1 antennas with an AM-6534/SSR-1 Amplifier-Converter for each antenna, an MD-900/

SSR-1 Combiner-Demodulator, and a TD-1063/SSR-1Demultiplexer (figure 2-8). The antennas are designedto receive transmissions at 240 to 315 MHz. Theantennas and antenna converters are mounted abovedeck so that at least one antenna is always in view of thsatell i te. The combiner-demodulator anddemultiplexer are mounted below deck.

The AN/FSC-79 Fleet Broadcast Terminal (figure2-9) interfaces the communications subsystems and thesatellite. The terminal provides the SHF uplink for the

Figure 2-9.AN/FSC-79 Fleet Broadcast Terminal.

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FLTSATCOM system and is used in particular tosupport the Navy Fleet Broadcast system. TheAN/FSC-79 operates in the 7- to 8-GHz band and isdesigned for single-channel operation. TheAN/FSC-79 terminal is installed at the fourCOMMAREA master stations andNAVCOMTELSTA Stockton, Calif.

The AN/WSC-3 Transceiver is the standard

UHF SATCOM transceiver for both submarine andsurface ships. The AN/WSC-3 is capable of operating in either the satellite or line-of-sight(LOS) mode and can be controlled locally orremotely.

The unit is designed for single-channel, half-duplex operations in the 224- to 400-MHZ UHFband. It operates in 25-kHz increments, and has 20preset channels. In the SATCOM mode, theAN/WSC-3 transmits (uplinks) in the 292.2- to311.6-MHz bandwidth and receives (downlinks) in

the 248.5- to 270.1-MHz band. A separate transceiveis required for each baseband or channel use.

The AN/WSC-5 UHF Transceiver (figure 2-the common UHF RF satellite terminal installed NAVCOMTELSTAs for the GAPFILLER subsystemIn FLTSATCOM operations, it is used as the commonRF terminal for all subsystems except the FleSatellite Broadcast (FSB) and the Antisubmarin

Warfare information Exchange Subsystem (ASWIXS)The AN/WSC-5 can be used to back up the AN/FSC79. The AN/WSC-5 transmits in the 248.5- to 312MHz range and receives in the 248.5- to 270.1-MHrange.

The AN/ARC-143 UHF Transceiver (figure is used for ASWIXS communications and is installeat VP Antisubmarine Warfare Operation Centers anaboard P-3C aircraft. The unit two parts: a transceiveand a radio set control. The AN/ARC-1

Figure 2-10. AN/WSC-5 UHF Transceiver.

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Figure 2-11.AN/ARC-143 UHF Transceiver.

can be used to transmit or receive voice or data in the255.0- to 399.99-MHz frequency range.

The systems discussed are only a few of theSATCOM equipments used by the Navy. Some of thereferences listed in Appendix III of this module areexcellent sources for more information on satelliteequipment and systems.

FLEET SATELLITECOMMUNICATIONS SYSTEM AND

SUBSYSTEMS

The F lee t Sa te l l i t e Communica t ions(FLTSATCOM) system and subsystems providecommunications links, via satellite, between shore

commands and mobile units. The system includes RFterminals, subscriber subsystems, training,documentation, and logistic support. Within each

satellite, the RF channels available for use have beendistributed between the Navy and the Air Force.

Equipments in support of the FLTSATCOM systemare on ships, submarines, aircraft, and at shore stationsThese equipment installations vary in size andcomplexity. Furthermore, with the exception of voicecommunications, the system applies the technology of processor- (computer-) controlled RF links and uses thassistance of processors in message traffic preparationand handling.

Although any part of the FLTSATCOM system canbe operated as a separate module, system integrationprovides connections for message traffic and voicecommunications to DOD communications networks.

A backup capability that can be used in the event oan outage or equipment failure is provided for bothshore and afloat commands. All subsystems have somform of backup mode, either from backup equipmentand/or systems, facilities, or RF channels. Thiscapability is built in as part of the system design andmay limit the ability of selected FLTSATCOM systemsto process information.

FLEET SATELLITE BROADCAST (FSB)SUBSYSTEM

The Fleet Satellite Broadcast (FSB) subsystem is anexpansion of fleet broadcast transmissions thathistorically have been the central communicationsmedium for operating naval units. The FSB transmitsmessages, weather information, and intelligence data toships. The shore terminal transmits this data on a direc

SHF signal to a satellite, where the signal is translated toUHF and downlinked. Figure 2-12 shows a standardFSB subsystem configuration.

Figure 2-12.Fleet Satellite Broadcast subsystem.

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COMMON USER DIGITAL INFORMATIONEXCHANGE SYSTEM (CUDIXS) ANDNAVAL MODULAR AUTOMATEDCOMMUNICATIONS SYSTEM (NAVMACS)

The CUDIXS/NAVMACS combine to form acommunications network that is used to transmitgeneral service (GENSER) message traffic betweenships and shore installations. NAVMACS serves as anautomated shipboard terminal for interfacing withCUDIXS (shore-based) (figure 2-13 ) and the FleetBroadcast System.

OTHER SPECIALIZED SUBSYSTEMS

The FLTSATCOM system represents a compositeof information exchange subsystems that use thesatellites as a relay for communications. The followingsubsystems satisfy the unique communicationrequirements for each of the different navalcommunities.

Submarine Satellite Information ExchangeSubsystem (SSIXS)

The SSIXS provides a communications system exchange message traffic between SSBN and SSNsubmarines and shore stations.

Antisubmarine Warfare InformationExchange Subsystem (ASWIXS)

ASWIXS is designed as a communications linantisubmarine warfare (ASW) operations betweenshore stations and aircraft.

Tactical Data Information Exchange

Subsystem (TADIXS)

TADIXS is a direct communications link betweecommand centers ashore and afloat. TADIXS provideone-way transmission of data link communications.

Secure Voice Subsystem

Figure 2-13.NAVMACS (V) communications interface.

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The secure voice subsystem is a narrowband UHFlink that enables secure voice communications betweenships. It also allows, connection with wide-area voicenetworks ashore.

Tactical Intelligence (TACINTEL)Subsystem

TACINTEL is specifically designed for specialintelligence communications.

Control SubsystemThe Control subsystem is a communications

network that facilitates status reporting andmanagement of FLTSATCOM system assets.

Officer in Tactical Command InformationExchange Subsystem (OTCIXS)

OTCIXS is designed as a communications link forbattle group tactical operations.

Teleprinter Subsystem (ORESTES)

ORESTES is an expansion of the existingteleprinter transmission network.

LEASAT TELEMETRY TRACKING ANDCOMMAND SUBSYSTEM

The LEASAT Telemetry Tracking and Commandsubsystem is a joint operation between the U.S. Navyand contractors for controlling LEASATS. Theinstallation of subsystem baseband equipment and RFterminals aboard ships and aircraft is determined bycommunications traffic levels, types of

communications, and operational missions.Since Fleet Satellite Broadcast message traffic is a

common denominator for naval communications, it isreceived by numerous types of ships. In someinstallations, such as large ships, the fleet broadcastreceiver represents one part of the FLTSATCOMequipment suite. A typical configuration on a large shipwould include fleet broadcast, CUDIXS/NAVMACS,secure voice, OTCIXS, TADIXS, teleprinter, andTACINTEL equipment.

The FLTSATCOM subsystems apply some form of automated control to the communications beingtransmitted with the exception of the secure voice andcontrol subsystems. This includes message or data link processing before and after transmittal and control of the RF network (link control) in which the messages arebeing transmitted. The automation of these functions ishandled by a processor.

Much of the message processing beforetransmission and after receipt is fully automatic anddoes not require operator intervention. The actualmessage or data link transmission is fully automatedand under the control of a processor. Within thelimitations of equipment capability, each subsystemaddresses the unique requirements of the user and theenvironment in which the user operates.

DEMAND ASSIGNED MULTIPLE ACCESS

(DAMA)DAMA was developed to multiplex several

subsystems or users on one satellite channel. Thisarrangement allows more satellite circuits to use eachUHF satellite channel.

Multiplexing

The number of communications networks beingused is constantly increasing. As a result, all areas of theRF spectrum have become congested. Multiplexing is amethod of increasing the number of transmissionstaking place in the radio spectrum per unit of time.

Multiplexing involves the simultaneoustransmission of a number of intelligible signals usingonly a single transmitting path. As we mentionedearlier, the Navy uses two multiplexing methods: time-division multiplexing (TDM) and frequency-divisionmultiplexing (FDM). We have already discussed FDMwith the AN/UCC-1. Additional informationconcerning both methods can be found in Radio-Frequency Communication Principles, NEETS,Module 17.

A UHF DAMA subsystem, the TD-1271/UMultiplexer, was developed to provide adequatecapacity for the Navy and other DOD users. Thissubsystem was developed to multiplex (increase) thenumber of subsystems, or users, on 1 25-kHz satellitechannel by a factor of 4.

This factor can be further increased by multiples of4 by patching 2 or more TD-1271s together. Thismethod increases the number of satellite circuits perchannel on the UHF satellite communications system.Without this system, each satellite communicationssubsystem would require a separate satellite channel.

Transmission Rates

The DAMA equipment accepts encrypted datastreams from independent baseband sources andcombines them into one continuous serial output data

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stream. DAMA was designed to interface the NavyUHF SATCOM baseband subsystem and the AN/WSC-5 and AN/WSC-3 transceivers.

The TD-1271/U Multiplexer includes a modemintegral to the transceiver. The baseband equipmentinput or output data rate with DAMA equipment can be75, 300, 600, 1,200, 2,400, 4,800, or 16,000 bits persecond (bps). The DAMA transmission rate on thesatellite link (referred to as burst rate) can be 2,400,9,600, 19,200, or 32,000 symbols per second.

Circuit Restoral/Coordination

When a termination is lost in either or bothdirections, communications personnel must observespecial guidelines. During marginal or poor periods of communications, the supervisors should assign adedicated operator to the circuit if possible.

When normal circuit restoration procedures areunsuccessful and/or a complete loss of communications

exists, an IMMEDIATE precedence COMMSPOTmessage should be transmitted (discussed earlier).Every means available must be used to re-establish thecircuit, including messages, support from other ships orNAVCOMTELSTAs, or coordination via DAMA if available.

The guidelines established in NTP 4, CIBs, andlocal SOPs are not intended to suppress individualinitiative in re-establishing lost communications.Circuit restoral is dependent upon timely action, quick decisions, and the ability of personnel to use any meansavailable to restore communications in the shortestpossible time.

SPECIAL CIRCUITS

During certain communications operations, youmay be required to activate and operate special circuits.Some of the most common special circuits are discussednext.

UHF AUTOCAT/SATCAT/MIDDLEMANRELAY CIRCUITS

Shipboard HERO conditions and emission control(EMCON) restrictions often prohibit transmission of RF below 30 MHz.

To provide an uninterrupted flow of essentialcommunications without violating HERO and EMCONrestrictions, AUTOCAT, SATCAT, and MIDDLEMANwere developed. With these techniques, the range of

tactical UHF circuits (voice or teleprinter) can beextended by relay of AM UHF transmissions via satellite. AUTOCAT accomplishes this using a shipwhereas SATCAT uses an airborne platform forautomatically relaying UHF transmissions.MIDDLEMAN requires an operator to copy themessages with subsequent manual retransmission.

The three techniques just discussed use three

different types of circuit for reception and relay oftransmissions. These circuits are as follows:

A voice circuit where some units send andreceive on one frequency, and other units senand receive on any other frequency;

A voice circuit where all units transmit on onfrequency and receive on another frequency

A RATT circuit where all units transmit on onfrequency and receive on another frequency.

FLEET FLASH NET

The Fleet Flash Net (FFN) is composed of seniooperational staffs and other designated subscriberspurpose of the FFN is to distribute high-precedence ohighly sensitive traffic among subscribers. A recethe net constitutes firm delivery, and the messagenot be retransmitted over other circuits to receiptinstations. The FFN is explained in more detail in MissiCommunications, NTP 11.

ANTENNA SYSTEMS

Operation of communication equipment over thentire range of the RF spectrum requires many types oatennnas. You will need to know the basic type of antennas available to you operationally, theircharacteristics, and their uses, Very often, you, theoperator, can mean the difference between efficieninefficient communications. You will have a choice omany antennas and must select the one most suitabthe task at hand. Your operational training will acqyou with the knowledge necessary to properly use thantennas at your disposal, However, your operationatraining WILL NOT acquaint you with the WHYantennas, in other words, basic antenna theory. Thfollowing topics are intended to familiarize you witbasic antenna terminology, definitions, andcharacteristics.

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ANTENNA CHARACTERISTICS

As you will learn in this section, all antennas exhibitcommon characteristics. The study of antennasinvolves the following terms with which you mustbecome familiar:

Antenna Reciprocity

The ability of an antenna to both transmit andreceive electromagnetic energy is known as itsreciprocity. Antenna reciprocity is possible becauseantenna characteristics are essentially the same forsending and receiving electromagnetic energy.

Even though an antenna can be used to transmit orreceive, it cannot be used for both functions at the sametime. The antenna must be connected to either atransmitter or a receiver.

Antenna Feed Point

Feed point is the point on an antenna where the RFcable is attached. If the RF transmission line is attachedto the base of an antenna, the antenna is end-fed. If theRF transmission line is connected at the center of anantenna, the antenna is mid-fed or center-fed.

Directivity

The directivity of an antenna refers to the width of the radiation beam pattern. A directional antennaconcentrates its radiation in a relatively narrow beam. If the beam is narrow in either the horizontal or verticalplane, the antenna will have a high degree of directivityin that plane. An antenna can be highly directive in oneplane only or in both planes, depending upon its use.

In general, we use three terms to describe the type of directional qualities associated with an antenna:omnidirectional, bidirectional, and unidirectional.Omnidirectional antennas radiate and receive equallywell in all directions, except off the ends. Bidirectionalantennas radiate or receive efficiently in only twodirections. Unidirectional antennas radiate or receiveefficiently in only one direction.

Most antennas used in naval communications areeither omnidirectional or unidirectional. Bidirectionalantennas are rarely used. Omnidirectional antennas areused to transmit fleet broadcasts and are used aboardship for medium-to-high frequencies. A parabolic, ordish, antenna ( figure 2-14) is an example of aunidirectional antenna. As you can see in the figure, an

Figure 2-14.Principle of parabolic reflection.

antenna (normally a half wave) is placed at the focalpoint and radiates the signal back into a large reflectinsurface (the dish). The effect is to transmit a verynarrow beam of energy that is essentially unidirectionaFigure 2-15 shows a large, unidirectional parabolicantenna. Directional antennas are commonly used at

shore installations.Wave Polarization

Polarization of a radio wave is a majorconsideration in the efficient transmission andreception of radio signals. If a single-wire antenna is

Figure 2-15.Unidirectional parabolic antenna.

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used to extract energy from a passing radio wave,maximum signal pickup results when the antenna isplaced physically in the same direction as the electricfield component. For this reason, a vertical antenna isused to receive vertically polarized waves, and ahorizontal antenna is used to receive horizontallypolarized waves.

At lower frequencies, wave polarization remainsfairly constant as it travels through space. At higherfrequencies, the polarization usually varies, sometimesquite rapidly. This is because the wave front splits intoseveral components, and these components followdifferent propagation paths.

When antennas are close to the ground, verticallypolarized radio waves yield a stronger signal close to theEarth than do those that are horizontally polarized.When the transmitting and receiving antennas are atleast one wavelength above the surface, the two types of polarization are approximately the same in fieldintensity near the surface of the Earth. When the

transmitting antenna is several wavelengths above thesurface, horizontally polarized waves result in astronger signal close to the Earth than is possible withvertical polarization.

Most shipboard communication antennas arevertically polarized. This type of polarization allowsthe antenna configuration to be more easilyaccommodated in the limited space allocated toshipboard communications installations. Verticalantenna installations often make use of the topsidestructure to support the antenna elements. In somecases, to obtain the required impedance match betweenthe antenna base terminal and transmission line, thestructure acts as part of the antenna.

VHF and UHF antennas used for ship-to-aircraftcommunications use both vertical and circularpolarization. Because aircraft maneuvers cause cross-polarization effects, circularly polarized shipboardantennas frequently offer considerable signalimprovements over vertically polarized antennas.

Circularly polarized antennas are also used for ship-to-satellite communications because these antenntasoffer the same improvement as VHF/UHF ship-to-aircraft communications operations. Except for thehigher altitudes, satellite antenna problems are similarto those experienced with aircraft antenna operations.

Standing Wave Ratio

Another term used in antenna tuning is standingwave ratio (SWR), also called voltage standing wave

ratio (VSWR). A simple definition could be therelative degree of resonance achieved with antenntuning. When tuning an antenna, you must understandthe SWR when expressed numerically.

You will hear SWR expressed numerically in nevery tuning procedure. For example, you will heasuch terms as three-to-one, or two-to-one. Yousee them written 3:1 SWR, 2:1 SWR, or 1:1 SWRlower the number ratio is, thebetter the match betwthe antenna and the transmitter for transmitting RFsignals. For example, a 2:1 SWR is better than a 3:1SWR.

As you approach resonance, you will notice thayour SWR figure on the front panel meters will bedrop to a lower numerical value. A good SWR isconsidered to be 3 or below, such as 3:1 or 2:1.Anything over 3, such as 4:1, 5:1, or 6:1 isunsatisfactory. The SWR becomes increasingly cras transmitter output is increased. Where a 3:1 SWR isatisfactory with a 500-watt transmitter, a 2:1 SWRbe considered satisfactory with a 10-kilowatt

transmitter.Most antenna couplers have front panel meter

show a readout of the relative SWR achieved viaantenna tuning. Figure 2-16 shows a multicouple

Figure 2-16.AN/SRA-33 antenna multicoupler

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is module 04 - communications hardware

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