lafd radio comm manual jan11

8/12/2019 LAFD Radio Comm Manual Jan11

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Los Angeles Fire Department

COMMUNICATIONSMANUAL

MILLAGE PEAKS, Fire Chief / Ch apter No. 1 / Date of Issue: 01/2011

RADIO COMMUNICATIONS OVERVIEW


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Chapter 1January 2011Page 2 of 52

Introduction 3Purpose 3

Standard Protocols 4

Emergency Operations 5

Radio Alarms 5

Size-Up 5

Use of Tactical Channels 8

Use of Command Channels 8

Radio Use Procedures 9

Dos and Donts 13

Continuing Dialog 14

Messages During High Activity 14

The Radio System 15

Base Station Transmit / Receive Sites 16

Data Radio Network 20

Dispatch and Control Centers 23

Mobile Radio Units 23

Portable Radios or Handi -Talkies 24

Radio Frequencies 25

Modes of Operation 32Department Capabilities 42

Battery Maintenance 48

Replacement Procedures 51


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Introduction

Radio communications for the fire service has evolved considerably over the last

60 years.Previously only the company officer was permitted to use a radio. Today, radiosare a critical safety tool that must be in the hands of every fire fighter at everyemergency scene. Technology advances quickly, as advances in radiocommunication technology occur, its important to make sure that radios remainan effective and reliable means of communication.

Specifically, new technology for radio communication systems must meet theunique demands of the job of fire fighting. Fire fighters must be able tocommunicate in cold and hot temperature extremes, in wet and humidatmospheres full of combustion byproducts and dust, while under or aboveground, inside and below buildings and in rubble piles. Other environmentalchallenges include loud noise from apparatus, warning devices, tools and the fireitself.

Any new radio communication system must take these factors into consideration.When talking about fire department communications systems usually we aretalking about what are traditionally called land mobile radio systems.

It is important for firefighters as well as fire officers to have a basic knowledge ofradio system technologies to help them effectively use the radio system.

Most radio system users do not need a detailed understanding of the technologybehind the systems they use. However, such knowledge is important for thoseinvolved in developing procedures for the use of the systems, and in training fieldusers to have a more comprehensive understanding of their operation. Alltechnologies have strengths and weaknesses, and understanding thosecharacteristics is important in making decisions related to the technologies.

Radio communications are the lifeline of the Los Angeles Fire Departmentsemergency operations.

In many instances, the outcome of an emergency is decided by either thesuccess or failure on the part of members to communicate effectively via radio.

PurposeThe purpose of this bulletin is to first, provide a standardized means forcommunication and second, explain the basic functions of the radio system.

As a general rule, most members have developed their radio communicationskills by listening to radio messages.


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The results understandably are a composite of abilities, skills, personaldifferences, and widely varying interpretations of what is correct.

Standardizing communications will eliminate useless messages and bring asense of professionalism to our daily duties.

Although many basic emergency operations procedures are standardized, thestate of the art in electronics is changing constantly. The effect is an ever-increasing change in our emergency communication procedures and equipment.Understanding the radio systems basic functions may help the user troubleshoota potential problem.

Standard ProtocolsThe life safety of both firefighters and citizens depends on reliable, functionalcommunication tools that work in the harshest and most hostile of environments.Firefighters operate in extreme environments that are markedly different fromthose of any other radio users. Firefighters operate lying on the floor; in zerovisibility, high heat, high moisture, and wearing self-contained breathingapparatus (SCBA) face pieces that distort the voice. They are challenged furtherby bulky safety equipment, particularly gloves, which eliminate the manualdexterity required to operate portable radio controls. Firefighters operate insidestructures of varying sizes and construction types.

The size and construction type of the building have a direct impact on the abilityof a radio wave to penetrate the structure. All of these factors must beconsidered in order to communicate in a safe and effective manner on the fireground.

The reasons for standardizing radio communications are numerous. Given thesubstantial cost, the citizens and their elected officials have a right to expect thehighest level of professionalism in radio communications. In addition, theFederal Communications Commission (FCC) issues guidelines and restrictionson the use of radio transmissions. If these guidelines and restrictions are notfollowed, the Department risks losing its assigned frequencies.

Currently all positions in the field are assigned a radio. Every year theDepartment becomes busier and more active with more radio messages beingtransmitted. Given this, the radio time must be conserved much like a naturalresource. Radio messages must be planned, concise and to the point. Aproperly communicated message will also save time by eliminating the need torepeat.

Often, the news media is present at the scene of emergencies. They are therenot only to film newsworthy events, but also to collect audio background tosupport the film. Actual LAFD radio transmissions are often used.


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When claims are filed with the City Attorney, the result is usually a lawsuit. Attorneys filing lawsuits against the LAFD routinely request all written andaudiotape records immediately before, during and after the incident in litigation.

Remember, all 18, 800 MHz radio channels MDT messages and phone calls into,and from Metro Fire Communications (MFC or Metro) are recorded on a 24-hour basis. Additionally, all radios are assigned a four-digit identification numberthat is transmitted and recorded each time a radio is keyed.

Emergency Operations Metro Fire Communications Channels (4, 7, 8, and 9) shall be used by field unitsfor communications as outlined in the Manual of Operation Section 2/1-00.00.For the most part, this includes the following types of messages:

1. Initial size-up.2. Request for additional resources.3. Request for special services and notifications, such as Los Angeles

Police Department, Department of Water and Power, etc.4. Rundown on resources responding.5. Location of command post, base or staging areas.6. Incident command designation (I/C Name).7. Change of command at an emergency.8. Knockdown of fire.9. Reporting resources available.

During emergency operations, it is important for members to utilize astandardized format of communicating on the incident tactical channel to theincident commander and/or other resources assigned to the incident.

A sound approach for members to follow for tactical communications would becommunications indicating at least the following. The conditions, their actions,and their needs.

1. General situation status ( CONDITIONS ):a. Incident conditions (fire location and extent, Hazmat spill or release,

number of patients, etc.)

b. Incident Action Plan (offensive, defensive, etc.)c. Status of the tactical priorities.d. Safety considerations.

2. Deployment and assignments of operating companies and personnel(ACTIONS ).

3. Appraisals of need for additional resources ( NEEDS ).


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Radio Alarms Acknowledgement A brief response to a radio alarm, i.e., Engine 1 or Engine1 is responding is sufficient acknowledgement to the dispatcher unless theaddress or other information clarification is required.

Standby For Dispatch Dispatchers will, time permitting, alert units on the radio,i.e. Engine 1, Battalion 2, standby for dispatch, allowing them to prepare foremergency responses.

Size-UpIf an emergency exists, an accurate size-up covering all pertinent information isrequired. If there is nothing showing it is only necessary to report that fact toMFC.

The fact that people are waving is of no value to MFC, and information that youare holding the assignment, will investigate, will give a report when you getmore information is all verbiage that is unnecessary and wastes radio time .

No size-up is required for a single company response unless help is needed orother situational changes require it.

The needs of MFC to obtain information from the scene of an emergency incidentis limited, but of critical importance to the outcome of an incident and to thedeployment of uncommitted forces. Operational needs of MFC from field unitsare as follows:

1. Section 2/1-001.00 of the Manual of Operation states that a size-up shallinclude, but is not restricted to the following information, as applicable:

a. Address of location of incidentb. Type of incidentc. Life hazardd. Assistance needede. Exposure problemsf. Location of Command Post

2. Initial size-up by the first officer on-scene. Be brief and to the point.Think of what you are going to say before you start talking on the radio.The initial size-up accomplishes the following:

a. Informs MFC that LAFD resources are on-scene.b. Determines response mode for balance of the assignment.c. Helps MFC handle additional calls for the same incident.d. Alerts MFC to the possible need to make move ups.e. Alerts incoming recourses of what to expect.


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3. As a general rule, size-ups by Rescue Ambulances or Fire Companiesresponding with Rescue Ambulances are not needed unless there areextenuating circumstances or a request must be made for assistance.

If a life threatening situation exists, i.e., CPR in progress, multiple gun shotwounds, etc., a brief size-up to an incoming company, on the EMSTactical Channel, is appropriate. With non-life threatening vital signs orno usual situation existing, a size-up is not necessary or required.

Extensive, detailed, or long , drawn out descriptions of the patientssymptoms are best described at the scene by a one-on-one contact.

4. A comprehensive size-up by the Incident Commander shall be made assoon as possible. The size-up includes, but is not limited to, thefollowing:

a. Correct addressb. Description of incidentc. Life hazardsd. Assistance needede. Special problems, i.e., exposures, weather, access, etc.f. Location of Command Postg. Approximate duration of incident

Updates or a continuing size-up should be made occasionally to MFC inorder to keep them informed of the progress of the incident and resource

requirements.

This would include information to the PIO for media dissemination.Generally, these updates would be made at the Chief Officer level.

5. Assistance needed from outside agencies. See Manual of OperationSection 2/1-00.00. Use proper terminology, especially when requestingthe police. Specify the type of problem or assistance needed, i.e., Metrofrom Task Force ___, we need Water and Power for high voltage wiresdown pole to pole; Metro from Engine ___, we need DOT for trafficcontrol; Metro from Rescue ___, we need PD. Specify the need so that

the urgency can be determined.

When requesting assistance from outside agencies, allow approximately30 minutes before requesting ETAs.

6. Availability of resources and Chief Officers. Companies, special units andChief Officers are made available by the Incident Commander. Whenmade available, the company, unit or chief officer is to return to their owndistrict unless directed otherwise by MFC.


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It is neither necessary nor desirable to include such comments asReturning to quarters, remaining on the radio or remaining on fireprevention. When becoming available from an incident it i s not necessaryfor units to verbally give that information to MFC. Utilizing the MDT issufficient.

Companies returning to their own quarters shall not direct MFC to releasethe move up companies. At no time shall any member specifically cancela re source of higher authority, i.e., Metro from Task Force 1, cancelBattalion 1. A more appropriate message would be, Metro from TaskForce 1 we can handle.

7. A press size-up is required, as soon as conditions permit, for thoseincidents that are newsworthy. A complete operational size-up meetsmost requirements of a press size up. A press size-up should emphasize

those aspects of an incident which are interest to the news media.

The press size-up shall not be made at the expense of the operationalrequirements.

The press size-up should be made on a channel which is not being usedat the time.

It should include the fact that it is a Code 20 Incident, if appropriate . Ifan incident escalates to a greater alarm or larger incident, a Code 20notification is automatic, verbal notification is not required.

Use of Tactical ChannelsThe purpose of Tactical Channels is to reduce the overall radio traffic on any onechannel.

This feature permits all units on a specific incident to communicate betweenthemselves without interference from other field operations or MFC. MFC doesnot normally monitor tactical channels. Therefore, they are ideally suited tohandle any form of communications not affecting MFC.

However, messages should be brief, concise and limited to essential informationin order to maintain a manageable level of radio traffic.

Emergency operations shall be handled to the extent possible on the assignedTac Channel. Conversations on these channels can be less formal andstructured, but are still required to remain businesslike.


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Use of Command Channels1. Channel 11 has been designated as the Departments Command

Channel. This channel is used by Chief Officers or members assigned incommand positions for emergency and non-emergency operations.

When a member wishes to contact the Metro Battalion Commander on theCommand Channel, they should first contact Metro on the dispatchchannel and state: Metro from Battalion ___, have the B/C meet me onChannel 11.

2. Channel 11 should be used by Chief Officers to communicate expandedmessages or comprehensive size-ups to MFC on working emergenciesafter the initial size-up.

3. During greater/major incidents, Channel 11 shall be monitored by theIncident Commander and OCD until such time as both agree todiscontinue its use.

4. Operationally, members other then Chief Officers may be assignedcommand functions (Division Supervisor, Group Supervisor, etc) whichmay require they monitor channel 11 for operational purposes. Membersshall do so as required by assignment.

Radio Use ProceduresIn addition to the use of radios at emergency incidents, radio communicationsplay a vital role in the day to day routine of the Department. This section willalso serve as a guide to non-emergency radio operations of the Department.

The Departments Radio Communication protocol is that radio communicationsshall be composed of plain commonly used English. With minor exceptions thisapplies to all Department radio communications. However, certain code wordsand abbreviations are acceptable for use on the radio, they are listed below:

Roger means that a radio message is received and understood, do notroger a message that should be answered with a yes or a no.

Cancelled means discontinue response, or you dont need the specificresource.

On the air or On the radio means a particular resource is monitoring theradio.

Covered means a stronger signal has interfered with and overpoweredanother signal, making the weaker signal unreadable.


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Code 20 a widely used code which indicates that an occurrence haspotential value to the news media.

A-Unit abbreviation for Arson Unit.

Available means ready for response within 60 seconds . You are eitheravailable or you are not.

Bravo Tango used at incidents involving bomb threats.

ETA estimated time of arrival.

Alert 2 Over land, an aircraft has, or is suspected to have an operationalissue that affects normal flight operations to the extent there is danger ofan accident.

Blue 2 Over water, an aircraft has, or is suspected to have an operationalissue that affects normal flight operations to the extent there is danger ofan accident.

Alert 3 An aircraft accident has occurred on, or in the vicinity of theairport.

Blue 3 An aircraft accident has occurred in the water.

In addition, the Department has adopted the standard International Phonetic Alphabet word list to be used when transmitting alphabetical letters to provideconsistency and eliminate repeated transmissions.

-Alpha -Juliett -Sierra-Bravo -Kilo -Tango-Charles -Lima -Uniform-Delta -Mike -Victor-Echo -Nora -Whiskey-Foxtrot -Oscar -X-Ray-Golf -Papa -Yankee-Hotel -Quebec -Zulu-India -Romeo

Members shall not use LAPD Code number, i.e., 390 down, etc.

Communicating with outside or supporting agencies Agencies outside the Los Angeles Fire Department (LFD) use somewhatdifferent terms and call signs to identify their respective dispatch centers or fieldunits.


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The most common agencies contacted via voice radio by LAFD members are theLos Angeles Police Department (LAPD), Los Angeles County Fire Department(LAC), Ventura County Fire Department (VNC), Angeles National Forest (ANF)and Verdugo Fire Communications Center (Figure 1 ). Verdugo FireCommunications is a joint dispatch center for the following agencies;

Alhambra Fire Department Arcadia Fire Department Burbank Fire Department Glendale Fire Department Monrovia Fire Department Monterey Park Fire Department Pasadena Fire Department San Gabriel Fire Department San Marino Fire Department Sierra Madre Fire Department South Pasadena Fire Department

To ensure clear communications with these agencies, the following should beconsidered when communicating with these respective agencies via radio.

LAPDLAPD dispatch is called control . For example, (control from Fire Rescue 11,has a unit been assigned to the reported assault at 7 th and Alvarado?)

Figure 1
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LACLos Angeles County Fire dispatch is called LA. For example, (LA from LAFDEngine 91, do you have units assigned to the reported incident on the southbound 14 freeway at Balboa?)

VNCVentura County Fire dispatch is called Ventura . For example (Ventura fromLAFD Truck 96, what unit is assigned to the traffic accident on the east bound118 freeway at Rocky Peak?)

ANF

U.S. For est Service, Angeles National Forest dispatch is called Angeles.

VERDUGO

Dispatch Center communications for any of the 11 agencies managed byVerdugo Communications Center would be addressed to Verdugo . Forexample, (Verdugo from LAFD Engine 77, what unit has been assigned to thetraffic accident on the north bound 5 freeway at Buena Vista?).

Human FactorsWhen we talk on the radio, each of us subconsciously performs a process beforewe speak. Managing this process will provide more effective communications.

Organization Before speaking, formulate what information is beingcommunicated and put the information in a standardized reporting template.For instance, a standard situational report might contain Unit ID, location,conditions, actions, and needs. This method forces users to fill in the blanks,answer all the necessary questions, and filter out unneeded information.

Discipline Often, ICs are overwhelmed by excess information on the radio.Radio discipline on the fire ground will help to determine if information needs tobe transmitted on the radio. If face-to-face communications are possiblebetween members of a crew and the information is not needed by the IC, dontget on the radio.

Microphone location Placing a microphone too close to the mouth orexposing the microphone to other fire ground noise may result in unintelligiblecommunications. When transmitting in a high-noise environment, shield themicrophone from the noise source. Hold the microphone a couple of inchesfrom the mouth or, when speaking through a SCBA mask, place themicrophone near the voice port on the face piece.

Voice level When speaking into a microphone use a loud, clear, andcontrolled voice. When users are excited, the speech often is louder andfaster. These transmissions often are unintelligible and require the IC to askfor a rebroadcast of the information, resulting in more radio traffic on thechannel.


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Managing these human factors will have a positive impact on fire groundcommunications. Reporting should be complete, necessary, and in a controlled,clear voice. These actions will reduce the amount of repeat transmissions on thefire ground, reducing air time.

Members are reminded when making radio transmission, there are fourconsiderations:

1. Think about what you are going to say.

2. Ask yourself if the message is necessary.

3. Keep it brief.

4. When you key the mike, be prepared to speak.

Do s and Donts

DO:1. Hold the press to talk button down momentarily BEFORE

transmitting. This keeps the first word in the message from beingclipped. Likewise, releasing the button prematurely will clip the endof the transmission.

2. Keep the microphone CLOSE to your mouth about one inch.

3. Speak into the microphone.

4. Speak in a normal, firm voice and speak clearly.

5. Give the complete message with the understanding that it will beheard. It is unnecessary and time consuming to call MFC first, wait fora go-head and then give the message.

6. Listen before talking.

7. Listen for acknowledge of radio messages to make certain themessage is received and understood. Radio messages notacknowledged are assumed not received.

8. Evaluate the importance of your message compared to others who areusing the radio at the same time.

9. Relay for other units when they have repeated their message.


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10. Answer for other units at the scene, if someone is trying to reach themand they do not answer. However, ensure the appropriate unitreceives the message.

11. Contact other mobile units directly (when possible) instead of relayingthrough MFC. Monitor your designated MFC Channel while on theradio.

12. Wait for other units that are talking to acknowledge their messagesbefore you begin your radio message.

13. Transmit only necessary messages. Keep messages clear, conciseand to the point.

DONT:

1. Personal messages of a non-business nature are strictly prohibited.

2. Allow the press to talk button to be left open , commonly called anopen mike. Inappropriate messages have been accidentallytransmitted in this manner.

3. Transmit too closely to another mobile unit or Hand-Held. This causesfeedback and garbles your message.

4. Use profanity, exchange pleasantries or offer personal greetings.

5. Put injured members names on the radio.

Continuing DialogueOnce a continuing dialogue is established with the dispatcher or a Field Unit, it isnot necessary to continue repeating your unit identification and other obviousinformation each time you key the transmitter.

Examples of improper or poor radio communications are:

Metro from E-29 requesting Public Works to assist in securing the firebuildings.

E-29 from Metro will you be needing plywood or barricades? Metro from E-29 we will ne ed sheets of plywood. E-29 from Metro are you requesting this or is Building and Safety

requesting it? Metro from E-29 Building and Safety is requesting it. E-29 from Metro roger.


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The proper use of radio time would be:

Metro from E-29 Building and Safety is requesting that Public Worksdeliver to the fire building 20 sheets of plywood to secure the building.

Roger.

Messages During High Activity All members shall be aware that during periods of high activity, careful thoughtmust be given to all necessary messages for clarity and brevity.

The Radio SystemThe LAFD has two different wireless communications systems. The first is the

voice radio system and the second is the data radio system . The voice radiosystem is the system commonly recognized because it is the system in which wereceive dispatches and talk from unit to unit every day. The voice radio systemis an Analog Conventional Simulcast system . Conventional Simulcast meansthat the system is not a trunked system and utilizes more then one repeater, orsend and receive sites to receive and transmit radio messages.

The data system carries our Mobile Display Terminal (MDT) communications. Itis not recognized as a separate system because the user interface is by pushinga button on the MDT. Because our interaction is limited, it is commonly notthought of as a radio system. However, they are separate and distinctly differentsystems.

The LAFD voice system operates in the 800 MHz range, and the data systemoperates in the 500 MHz range.

Each of t he Departments radio system s are a combination of several distinctcomponents. The most important of those components, the operator, wasdiscussed in the previous portions of this Training Bulletin. The othercomponents, that act to support the operator, will be discussed here.

In addition to the systems described above, the Department has additionalsimplex or directdigital channels in the 700 MHz band programmed in theXTS 5000 portable radios carried by all members, and the XTL 5000 mobileradios installed in late model apparatus. These channels are available for useonly in simplex or direct mode at this time.

There are three 700 MHz digital channels licensed to the LFD located at the endof Zones 7, 8 and 9, accessed via the front panel key pad identified as channels7TAC19D, 7TAC20D and 7TAC21D. 7 identifies it as a 700 MHz channel,TAC19 identifies the channel number and the D identifies the channel as adigital channel.


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There are additional 700 MHz National Emergency Response Interoperabilitychannels in Zone 7, beginning with 7TAC51D available as required

Base Station Transmit/Receive SitesThere are 10 strategically located remote transmit/receive sites serving the LAFDvoice radio system (Figure 2 ). While each of these sites appears different to theeye, their basic functions are still the same. These sites include the following;

1. Oat Mountain2. Beverly Glen3. Verdugo Peak4. Mt. Washington5. KSKQ6. 100 Wilshire7. Baldwin Hills8. San Pedro Hill9. City Hall East10. Mt. Lukens (City wide voice back-up system)
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Figure 2


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Figure 3


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MFC, OCD or the backup signal office located at Fire Station 108 (Coldwater)can send signals to the transmitter either by wire, microwave or by a combinationof both. The transmitter could also receive a signal through a repeater. Oncethe repeater receives a signal it then amplifies that signal to a predeterminedlevel as it is broadcast out over a geographic area.

The fixed site transmit/receive site located at Mt. Lukens is the Departmentsback-up radio system . It offers full 18 channel capability to repeat radiotransmissions, but it does NOT offer full coverage or access to the simulcastsystem which will be covered later in this bulletin. Mt. Lukens location isdepicted in (Figure 3 ).

Even though Mt. Lukens is considered a back-up radio system; there areimportant points to bear in mind.

1. The Mt. Lukens system is truly independent of the simulcast system. It isnot connected to the nine site simulcast system for transmit purposes untilit is turned on. When it is turned on, the simulcast system for the selectedchannels must be disabled.

2. The Mt. Lukens site is located on a very prominent point overlooking thearea around Battalion 12. It provides highly expanded system capabilityin the city and surroundings areas of the valley, especially in the area ofBattalion 12 (For example; Vogel Flats).

3. Even though Mt. Lukens is not transmitting with the simulcast system; it is

listening in base station mode at all times. For example, if a memberwere working for in a shadowed deep canyon or drainage in the hillsabove Battalion 12, it is very likely that Metro or OCD would hear radiotransmission as if they were coming over the simulcast sites. However,the dispatcher has no way of knowing which site is receiving radio traffic.Responses from the dispatcher to the field unit may be extremely poor, ornonexistent, but the dispatcher will hear the field unit fine. This isbecause of the full time listening mode and its geographic location lookingdown into the valley.

If this were the case, the Incident Commander might ask the dispatcher to

change over to the Mt . Lukens system on the selected channel. In thisinstance, Metro would turn off the selected channel on the simulcastsystem and turn on the channel at Mt. Lukens, thus providing Metro thecapability to talk back to the field unit.


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4. Mt. Lukens is a repeater site. Field units can only connect to it in repeatmode. When Mt. Lukens receives a voice radio message on the up leg,frequency; it repeats it on the down leg frequency . This provides thecapability for field units to communicate even though they may be ondifferent sides of a ridge line that defy normal communications. See(Figure 4 ).

Figure 4

Data Radio NetworkData radio network (MDT) coverage is provide through 6 fixed sites located asdepicted in (Figure 5 )

1. Oat Mountain2. Verdugo Peak3. Mt. Lee

4. Elysian Park5. 100 Wilshire6. San Pedro Hill
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Figure 5


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There are several fixed microwave links to relay MDT messages to fixed radiosend and receive sites located at strategic points in the City. These relay pointsare located at.

1. Van Nuys City Hall2. Baldwin Hills3. South East Los Angeles4. San Pedro City Hall

Their location has no direct impact on the end user, the firefighter. These sitesserve to link or connect the various send and receive sites into an integratedsystem.

There are several reasons multiple transmit/receive repeater sites are locatedthroughout the City of Los Angeles.

1. Signal Strength

The FCC limits transmitter power to a level that would not adequatelycover the entire city even if is was flat. LAFD radio transmittersamplify signals to a maximum of 155 watts. Contrast that to KMPC-

AM, for example, which transmits with 50,000 watts of broadcastpower. Yet, even with this powerful broadcast there are areas upcanyons, behind building/mountains, etc. that do not receive a signal.Therefore in order to cover the city as well as reasonably possible, theLAFD radio system is built around multiple transmit/receive sites.

2. Geographic and Topographic

Mountains, valleys, and distances limit the effectiveness of radio wavebehavior. They effectively are physical barriers.

3. Radio Wave Behavior

The 800 MHz frequency band used by the LAFD is a more compactand powerful wave when compared to VHF (100 MHz) or UHF (500MHz) bands. VHF signals tend to crawl over hills and up canyons .While the 800 MHz signal tends to be more limited to line of site.

However, the 800 MHz wave tends to be more penetrating, workingbetter inside buildings and underground.

4. Technical Limitations Along with power limitations, the FCC limits the LAFD to certainfrequencies. It is under these confines of the FCC the LAFD systemmust operate.


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5. System Redundancy

Multiple repeater sites with overlapping area of coverage allow thesystem to provide complete, or near complete coverage even if onerepeater site were to become non-operational. It is this sameoverlapping coverage that enhances the coverage in the canyons,valleys and in-building coverage.

Each transmitter site has a companion receiver site. In some cases, such as MtLee, the two are closely located. At other locations, such as Oat Mt, thetransmitter and receiver sites are some distance apart. For technical reasons,transmitters and receivers must be separated as a means of reducinginterference between the two. There are two basic means of achieving therequired separation; vertical, as at Mt Lee and horizontal, as at Oat Mt.

Dispatch and Control CentersThe Department currently has two dispatch and control centers. In ourDepartment, these are recognized as OCD and Coldwater . The new Metro Fire Communications (radio ide ntification Metro) dispatch center is currentlyunder construction and is scheduled to be completed in mid 2011. Oncompletion, MFC will be the primary dispatch and control center and the existingOCD facility will assume a back -up role.

OCD is currently the primary dispatch and resource accountability location forDepartment resources. Coldwater, located at Fire Station 108, is the back -updispatch and resource accountability center.

The Coldwater Center can carry out all of the functions of the primary center(OCD), but at a somewhat reduced capacity. Physically, it is not nearly as largeas OCD, there are limited dispatch consoles, but the 911 call answering,emergency trigger function and all other dispatch functions remain in place.

Mobile Unit RadiosMobile Radios (Figure 6 ) installed indepartment vehicles have the same basicfeatures and requirements of a base stationbut are much more limited in ability. The 800MHz mobile units transmit at 35 Watts. In amobile application, there is minimalopportunity to separate transmitters fromreceivers.

Figure 6
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To achieve separation, the receiver is automatically turned off when the transmitunit is keyed. Because antenna locations are limited to the vehicle; buildings,trees, hills, overpasses, other apparatus, etc., interfere with performance qualityof the mobile radios. Members need to recognize the impact and take this intoconsiderations when spotting apparatus, especially when ensuringcom munications is essential, such as when assigned as MedicalCommunications on a multi -casualty incident.

Parking apparatus with consideration for radio communications at emergencyincidents generally receives low priority, but it is a consideration that must beaddressed.

In extreme circumstances, to provide maximum coverage for selectedgeographic areas, it may be necessary for commanders to locate in an areawhich provides maximum coverage for select areas. In such circumstances,

commanders should consider locating at the following locations.

Battalion 1 Dodger Stadium South East Parking lotBattalion 2 Mt. Washington GlenalbynBattalion 3 Baldwin HillsBattalion 4 Baldwin HillsBattalion 5 Mt. LeeBattalion 6 San Pedro HillBattalion 7 KSKQ RFS47Battalion 9 Roof of 100 Wilshire/SP as B/UBattalion 10 Beverly Glen / FS99

Battalion 11 Mt. LeeBattalion 12 Verdugo PeakBattalion 13 Baldwin HillsBattalion 14 Verdugo PeakBattalion 15 Oat Mountain (east end of ridge)Battalion 17 Oat Mountain (west end of ridge)Battalion 18 Baldwin Hills

Portable Radios or Handi -Talkies Portable radios (Figure 7 ) have the same basic features as the mobile units and

base stations but are even more limited in ability, especially in the transmitphase. LAFD portable radios transmit 2 or 4 Watts of power (depending onmodel) and have a transmit range of up to about 2-3 miles in simplex or directmode under the best of conditions. Portability rather than transmit power is theprimary value of portable radios.


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LAFD Portable radios are provided to the field in 3 differentbands. 700/800 MHz, UHF and VHF. Though these radiosappear the same, they are in fact quite different. The best wayto differentiate between the radios is as follows;

The 700/800 MHz radio has a red band on the antennaand red lettering.

The UHF Radio has a blue band on the antenna andhas a blue face and blue lettering.

The VHF radio has a white band on the antenna , has awhite face and has white lettering.

Additional special purpose radios are provided for specificapplications such as marine and aviationcommunications.

800 = Red UHF = Blue VHF = White

BASIC RADIO COMMUNICATION TECHNOLOGY

Radio FrequenciesRadio communications are possible because of electromagnetic waves. Thereare many types of electromagnetic waves, such as heat, light, and radio energywaves. The difference between these types of waves is their frequency and theirwavelength.

The frequency of the wave is its rate of oscillation. One oscillation cycle persecond is called one hertz (Hz). The types of electromagnetic energy can bedescribed by a diagram showing the types as the frequency of the wavesincrease. (Figure 8 )

Figure 8

Figure 7


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When describing the frequencies used by common radio systems, the metricsystem is used to quantify the magnitude of the frequency. A typical frequencyused in fire department radio systems is 154,280,000,000 Hz. This is afrequency designated by the FCC as a mutual-aid radio channel . Dividing thefrequency by the metric system prefix mega, equal to 1,000,000, this becomes154.280 megahertz or MHz.

Land mobile radio systems are allowed to operate in portions of the radiospectrum under rules prescribed by the FCC. These portions of the spectrumare called bands, and land mobile radio systems typically operate withfrequencies in the 30 MHz (VHF low), 150 MHz (VHF high), 450 MHz (UHF), 700MHz, and 800 MHz bands.

The wavelength is the distance between two crests of the wave. The frequencyand wavelength are inversely related so that, as the frequency of the waveincreases, the wavelength decreases.

The length of a radio antenna is related to the wavelength with which the antennais designed to operate. In general, the higher the frequency of the waves usedby the radio, the shorter the antenna on the radio. (Figure 9 )

Figure 9


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Currently the LAFD uses four different frequency bands. The bands are definedas follows:

1. 800 MHz The primary radio used for LAFD operations. Portableradios are indicated with red engravings and a red antenna band.

2. 700 MHz Digital simplex channels which can be used for drills andfor emergency operations for non-critical messaging. The 700 MHzband is programmed into the red700/800 MHz band radios.

3. Ultra High Frequency (UHF / 500 MHz) Used for mutual aid incidentswith surrounding fire and police agencies. Also used for HospitalBase Station contact. UHF Portable radios are indicated with blueengravings and a blue antenna band.

4. Very High Frequency (VHF / 100MHz) Used by surrounding fireagencies for tactical and routine operations. Also used as the HospitalEmergency Administrative Radio (HEAR). VHF Portable radios areindicated with white engravings and a white antenna band.

The LAFD is only licensed to use the 700 MHZ and 800 MHz bands. The Los Angeles City repeaters for the LAFD system operate only in 800 MHz. Use ofthe UHF or VHF radio is prohibited unless used in a mutual aid scenario.Furthermore, the repeaters used when operating the UHF and VHF radios arenot property of LAFD.

There are mutual aid channels in the 800 MHz band that are identified as statewide fire and law enforcement mutual aid channels which the LAFD doessupport, these channels include.

1. Firemars (Fire Mutual Aid Radio System)2. Clemars (California Law Enforcement Mutual Aid Radio System)

Radio Wave PropagationTo send a radio signal from a transmitter to a receiver, the transmitter generateselectromagnetic energy and sends that energy through a transmission line to anantenna. The antenna converts the energy into electromagnetic radio waves that

travel at the speed of light outward from the antenna. If another antenna islocated in the path of the waves, it can convert the waves back into energy andsend that energy through a transmission line to a receiver. (Figure 10 )


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Figure 10

Radio signals emitted from an antenna travel both a direct path to the receivingantenna, and a path reflected from the ground or other obstacles. This reflectioncauses the wave to travel a longer distance than the direct wave, as shown in(Figure 11 ).

Figure 11


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The waves traveling over the reflected path then interfere with the direct waves,causing an effect know as multipath interference. Multipath interference causesa variation in the signal level at the receiver. The signal may be higher or lowerthan the di rect signal depending on the position of the receivers antenna . As theantenna is moved around, the signal varies, and the user hears a signal thatgoes from strong and clear to weak and noisy.

Radio waves can travel through some materials, such as glass or thin wood, butthe strength is reduced due to absorption as they travel through. Materials suchas metal and earth completely block the waves due to their composition anddensity. In addition, some materials will reflect radio waves, effectively blockingthe signal to the other side. In part, this is why the 800 MHz band is moreeffective for building penetration. The radio waves are small enough to gobetween the steel frame and metal reinforcing bars.

Because buildings are built from many types of materials, the radio waves can bepassed through some, be reflected by some, and be absorbed by others. This,along with the complex interior design of a building, creates a very complexenvironment for radio communications inside a building.

What Affects System Coverage?The coverage of a radio communications system generally is described as theuseful area where the system can be used reliably. Many factors affectcoverage, including the radio power output, antenna height and type, andtransmission line losses. However, the factor that most influences coverage isthe height of the antenna above the surrounding ground and structures(Figure 12 ).

By locating the antenna on a tower or mountain top, the system provides a moredirect path from the transmitter to the receiver. In the case of one radio usertransmitting directly to another radio user, having the radio antenna as high asfeasible (hand held at shoulder height) significantly improves coverage.

In land mobile radio systems like those used by the Department the antennas arevertically polarized . You can see evidence of this with the wire antennasmounted on the roofs of vehicles. Like car antennas designed for frequencymodulation (FM) broadcast radio, they stick up vertically from the surface of thevehicle.

The radiation pattern of the antenna is the shape of the relative strength of theelectromagnetic signal emitted by the antenna, and this depends on the shape ofthe antenna. The radiation pattern can be adjusted through antenna selection toprovide coverage where desired and to minimize coverage (and, in turn,interference) in undesired directions.


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Figure 12

Fixed-Site Antennas

Fixed-site antennas are mounted on towers or buildings to provide the dispatchor repeater coverage throughout the city. The antennas used are designed tooperate in the systems frequency band and, for b est power coupling, have acenter frequency as close as possible to the actual operating frequency.

The radiation pattern for the antenna is selected to provide a signal in the desiredsections of the coverage area, and have minimal coverage outside the desiredcoverage area. This will help ensure that the system is not interfering with othersystems unnecessarily. The most basic practical antennas are omni-directional,and have approximately equal coverage for 360 degrees around the antenna.

Mobile and Portable AntennasIn general, all mobile and portable radio antennas are omni-directional to providecoverage 360 degrees around the radio user. Vehicle antennas are mounted sothat they are not obstructed by equipment mounted on the top of the vehicle.

Light bars, air conditioning units, and master-stream appliances are some typicalobstructions found on fire vehicles. Some obstructions cannot be avoided, andthe designer must select the best compromise location.


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Vehicle antennas mounted on the roof of fire apparatus can be damaged byoverhead doors, trees, and other obstructions such as members walking on theroof for maintenance. Ruggedized low-profile antennas often are a better choiceand are utilized on Department apparatus whenever possible even if they have alower gain than a normal whip antenna. A properly mounted intact antenna witha lower gain is much better than a damaged antenna of any type.

Portable antennas usually are provided by the portable radio manufacturer andare matched to the radio. In some cases alternative antennas can be selectedfor the radio to overcome specific user conditions. However, in the applicationsfor the LAFD, antennas are not interchangeable and antennas from radios of adifferent band shall not be used on other radios. Always match an 800 MHz(red) antenna to an 800 MHz radio, a UHF antenna (blue) to a UHF radio and aVHF (white) antenna to a VHF radio. Radio performance will be seriouslydegraded by swapping out for an incorrect antenna.

When a portable radio is worn at waist level, such as with a belt clip or holster,the users body absorbs some of the signal transmitted or received by the radio .In addition, the antenna is at a much lower level than if the user were holding theradio to his or her face for transmitting. If a user is in a situation where theyneed to enhance radio performance, if safe to do so, raise the radio up abovehead level then attempt communications again.

InterferenceRadio frequency interference can be either natural or manmade. Interferencefrom internal noise occurs naturally in all electronic equipment due to the natureof the electronic circuit itself. Manufacturers take this into account duringequipment design, and obtaining a low-noise design is not particularly difficult. Inaddition, natural noise is produced by sunspot activity, cosmic activity, andlightning storms. This noise usually is of small magnitude and not significant formost land mobile radio communications. However, the VHF low band is affectedsignificantly by severe sunspot activity, sometimes to the point of completelyprohibiting communications.

More significant to radio communications systems is the interference producedby manmade sources. Vehicle ignitions, alternators, electric motors, high-voltagetransmission lines, computers, and other equipment with microprocessors also

emit radio signals that can interfere with Department radios.In general, manmade interference decreases with an increase in frequency. TheUHF band and, initially, the 800 MHz band are much less susceptible tomanmade interference than the VHF low and high bands. When systems are notsubject to significant interference, they are said to be noise limited, in contrastto interference limited.


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The increase in the number of transmitters used by cellular telephone companiesin the 800 MHz band has created increasing interference in the 800 MHz band.

Radio communication takes place using electromagnetic waves that travel fromthe transmitter to the receiver. These waves can be reflected or absorbed bymaterials such as buildings, the earth, or trees, reducing the strength of the wavewhen it reaches the receiving antenna. Elevating the transmitting or receivingantenna will reduce the likelihood of the wave being affected by buildings ortrees, because the path to the receiver will be more direct.

LAFD DIRECT AND REPEATED RADIO SYSTEMS

Modes of Operation There are three basic modes of operation for a radio system; Simplex, Duplexand Simulcast .

In Simplex, one frequency is used, the transmitting radio is in direct mode, allreceivers and transmitters are tuned to the same transmit and receive frequency.When one unit is transmitting, all other units in the area are able to receive.Units are able to communicate affectively as long as they are within range.(Figure 13 )

Figure 13


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The receiving radios will receive the transmitting unit message regardless if theyare simplex or duplex mode. However, to transmit back to the originating unit,the receiving unit must also be in the simplex mode.

What is necessary to understand is that in simple x or direct mode, t he signaltransmitted by the broadcasting unit is transmitted on the down leg frequency ofthe duplex or repeat channel .

In Duplex mode, two frequencies are used . The up leg frequency is definedas mobile to base. The down leg frequency is defined as base to mobile .(Figure 14 )

This system is used when communicating with OCD or access the simulcastsystem by having the radio in repeat mode. In repeat mode, the transmitting unitis broadcasting on one frequency (the up leg), it is received by the repeater site

and rebroadcast on the down leg on a second frequency, where it received byreceiving units.

Figure 14


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When a radio system must cover a large area, but the number of availablefrequencies is limited, a simulcast transmitter system may be the solution. Withthis system, multiple transmitters simultaneously transmit on the same frequency.

The transmitters must be precisely synchronized so that the signals they transmitdo not interfere with each other. In addition, the audio source sent to thetransmitters must be synchronized so that the radio user hears the same signalfrom each transmitter. The system consists of a simulcast controller and two ormore simulcast transmitters. In the case of the LAFD, nine sites aresynchronized. The advantages of a simulcast system are the coverage of alarge area, with high signal levels throughout the area, while using only a singlefrequency.

The Simulcast mode is used when transmitting mobile to mobile in the repeatmode. With this system a mobile or portable radio, or OCD can be heard

throughout the city. In the Simulcast mode the up and down leg frequenciesare used. The up leg is known as the transmitting frequency the down leg isknown as the receiving frequency.

In the simulcast system, a radio message transmitted in repeat mode is sent outon the up leg frequency, the weaker signal is received by the transmit/receivesite and then is rebroadcast at a much high er output power on the down legfrequency. (Figure 15 )

Figure 15


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The difference in duplex and simulcast systems is that the simulcast systemsends out the down leg at all transmit sites, thereby maximizing coverage tounits in the field.

When OCD broadcasts a voice message over the radio, it is going out on thesimulcast system, thus ensuring the maximum coverage is possible at all times.

It is important for members to understand the concept of simplex and duplexradio operations. There are distinctive applications for each mode. Forexample, if a member were working inside on a structure fire and was unable toestablish communications with other units on the scene in duplex mode, a switchto simplex mode would be appropriate and may well resolve the communicationsproblem. It is possible that the radios waves are blocked from reaching arepeater site. Bear in mind, with the switch to simplex mode, the member istransmitting on the down leg frequency and will be h eard by other units on

scene.

Receiver Voters Improve Field Unit to Dispatcher CommunicationsOCD is connected to nine high-powered transmitters to provide the dispatchcenter with a high level of talk-out capability. The transmitters are elevated toachieve better line-of-sight communications with the service area. High-poweredtransmitters ensure that OCDs transmissions are heard throughout the city andprovide some level of in-building coverage.

Portable radios have limited power and cannot always transmit a signal strongenough to reach all the transmitter sites. To provide a more balanced system,

receivers are networked together throughout the city in a receiver voter system(RVS). When a voice radio signal is received, a comparison of the receivedaudio signal takes place in a receiver voter. The receiver voter and its network ofreceivers are referred to as the RVS. The RVS usually is located at tech controlat OCD. The receiver voter compares the audio from all receivers and routes theaudio from the receiver with the best audio quality to the dispatcher. This type ofsystem provides very reliable fire ground communications.

Voice Loggers / MDT MessagingIt is of interest to all members to understand that all 18 LAFD 800 MHZ channelsare recorded 24 hours a day, seven days a week. This recording however is

only done when the radios are operated in the duplex mode . That is, voiceradio recording only occurs on messages that are transmitted on the up legfrequency and recorded as they are received at the repeater site selected by thereceiver/voter system.


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In addition to voice radio logging, all MDT transmissions are logged, timestamped and retained on file for future reference. Members are reminded tokeep this in mind and keep messages pertinent to Department operations.

Digital RadiosBecause the LAFD has incorporated digital communications technology into ouroperational radios, it is important for members to understand the difference in thetechnology from analog.

To improve audio quality and spectrum efficiency, radio manufacturersintroduced digital radios. This was a necessary move based on the FCCrequirements to continue narrow banding or reducing the band width of a radiosignal into a narrower band range.

In the digital world when a user speaks into the microphone the radio samples

the speech and assigns the sample a digital value. A vocoder (voice coder) orcodec (coder/decoder) in the radio performs the function of converting analogvoice to a digital data packet.

The digital data packet can vary in the number of bits. The higher number of bitsin the data packet, the higher the level of precision. Numerous samples aretaken each second to reproduce the source audio. The higher sample rate persecond and number of bits per sample result in increased audio quality. Forexample, compact disc (CD)-quality audio samples 44,100 times per second andthe number of graduations in the sample is 65,536. The use of digital audio wasexpected to reduce static and increase the range of radios in weak signal

conditions.

Digital Audio Processing A vocoder in a digital radio converts analog voice to a digital interpretation froman audio sample. Digital radios, unlike CD or DVD audio, have very limited datarates. Even cell phones have higher data rates than a digital radio. Because oflimited data rates, digital radio audio is sampled at a much lower rate with lessprecision. Designers of the portable radio vocoders felt the radios did not needthe same level of precision as CD-quality audio, since reproduction of humanspeech was the goal.

This is a basic explanation of how analog voice is processed by the radio.

Transmitting radio:1. The user keys the transmit key and speaks into microphone.

2. The audio is sampled and converted to a digital interpretation by ananalog to digital converter (A/D converter).

3. The vocoder converts the digitized speech into digital data.

4. The modulator modulates the radio frequency (RF) with the digital data.


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5. The modulated RF signal is boosted in power by transmitter amplifier.

6. The signal is transmitted from the radio antenna.

Receiving radio:1. The modulated RF is received by antenna.

2. The received RF signal is boosted to a useable level by the receiveamplifier.

3. The signal is demodulated by a demodulator. This removes the RFcomponent of the signal leaving the digital data component.

4. Digital data is decoded by the vocoder into digitized speech.

5. Speech data is converted to an analog signal by a digital to analogconverter (D/A converter).

6. Analog is sent to the speaker (Figure 16 ).

Figure 16

Analog versus Digital Signal Variations with Signal Strength As the radio user travels further from the transmitting radio, the signal strengthdecreases. The signal strength directly affects the ability of the radio toreproduce intelligible audio.

In an analog system, the clarity and intelligibility of the transmission, as receivedby the user, decrease directly as the signal level decreases. The noise (static) inthe signal progressively increases in strength, while the desired signaldecreases, until the transmitting user cannot be heard over the noise. When adigital user transmits to a receiver, the transmitted signal decreases just as theanalog signal does. However, the error correction in the digital transmissioncontains extra information that allows the audio information to be heard even witha large decrease in signal level.


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As the receiver travels further from the transmitter, the signal level decreases tothe point where the error correction cannot correct all errors in the signal.

When this point is reached, the receiving users will hear some distortion in thesignal and may hear some strange non-speech noises.

These strange non-speech noises are sometimes called Ewoking after thelanguage spoken by the Ewok characters in the movie Star Wars .

Once this point is reached, a small reduction in signal level will cause the numberof errors to exceed the ability of the system to compensate, and all audio will belost.

The problem this causes is that the radio signal goes from usable to unusablewith little or no indication that this is about to occur. With an analog radio

system, the signal slowly gets noisier, giving the user hints that the signal isgetting weaker. This behavior adds to the situational awareness of the user andallows him/her to make decisions about the environment. Although digital radiosprovide a larger range of usable signal levels, the lack of advance indication ofsignal level decrease allows users to get closer to complete loss ofcommunication without any advance warning.

Bidirectional Amplifiers Another solution to improving communication between field units inside buildingsor tunnels and dispatch and other on-scene units is the bidirectional amplifier(BDA). BDAs can be used with duplex and simulcast radio systems to extendcoverage from inside the structure to the outside of the structure and vice-versa,but BDAs do not operate with simplex radio systems.

To overcome radio system in-building coverage difficulties, BDAs often are usedto rebroadcast the system in buildings. There are many types of BDAs; allrequire electrical power and some type of antenna system. Often the antennasystems are installed in the plenum spaces of commercial structures. Theseantenna systems are generally nothing more then plastic coated coax cablewhich runs to the amplifier. The amplifier is generally located in acommunications or alarm system room.

Most BDA systems include battery backup power to keep it operational if a lossof commercial power occurs.

BDAs work well for incidents such as EMS calls and law enforcement incidentswhere there is no fire involvement in the building or building systems. In astructure with active fire, the building and building systems are affected directly.
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The building environment changes with the introduction of fire: Temperatures riseand particulate matter is suspended in the atmosphere. Firefighter actions toeliminate the fire can also have a detrimental effect. As water is applied to thefire, steam is generated and may have an effect on electronic equipment.

The moisture mixes with the suspended materials, and acids are formed. Theseacids can cause intermittent failure of exposed electrical contacts over time.

As with all electronics, BDAs are subject to failure when exposed to high heatand moisture. Other actions taken during firefighting operations also coulddestroy the BDA system. Firefighters checking for extension using pike polesmay inadvertently tear the BDA antenna system down, rendering the BDAuseless and causing loss of communications inside the building. (Figure 17 )

Figure 17

A list of building in Los Angles with BDAs to enhance LAFD communicationincludes the following.

1. Nokia Theatre2. Getty Center3. City Hall East4. Staples Center5. MTA Tunnels

As Fire and Building Codes are updated and modernized, this list can beexpected to grow.


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TRUNKED RADIO SYSTEMSCurrently, the LAFD has Verdugo dispatch programmed into the UHF (blue)portable and mobile radios carried by personnel and installed on late modelapparatus. Therefore, it is important for members to have a basic understandingof trunked radio systems.

Trunked radio systems are complex radio systems that were developed toimprove the efficiency of the use of available radio spectrum.

In conventional (non-trunked) radio systems, such as the LAFD simulcastsystem, a radio frequency is dedicated to a single function. When the radiofrequency is not in use, it cannot be used by another function. Trunking borrowstechnologic concepts from telephone systems to assign radio frequencies toactive calls, improving the efficiency of frequency use.

Like a conventional repeated radio system, trunked radios communicate witheach other through two or more repeaters.

In a trunked system, the radios often are known as subscriber units and a voicecommunications exchange is known as a call. A basic trunked radio system hasa system controller that controls the assignment of the repeaters, called voicetraffic repeaters, to individual calls.

For example, the radios communicate with the system controller to request theuse of a voice traffic repeater, by sending data messages to the system controlleron a special dedicated channel called the control channel. The system controlleracknowledges these communications and sends information to the radios usingthe control channel as well. The radios also can communicate some informationusing the voice traffic channels after a call has been terminated.

The voice traffic repeaters are shared among all users of the system; they alsoare known as resources .

The radio industry uses the term talkgroup to distinguish among physicalfrequencies or channels used in conventional radio systems. This terminologyoften is confusing, since from the actual radio users point of view a talk groupand a conventional channel are the same; they are both communications paths.

The distinction is made by the technologists to differentiate a physical channel orfrequency from the logical channel or talk group.

The system controller and other parts of the trunked radio system maintain a logof all activity that occurs in the system, as well as statistical information on theoperation of the system. These system logs can be used in the event of asuspected anomaly in the operation of the system to help determine the cause.


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GENERAL TRUNKED RADIO OPERATION

Radio On/Off Registration/Deregistration/Talk group AffiliationWhen a trunked radio is powered on initially, it begins operation by telling thesystem controller that it is active, along with the talk group currently selected onthe radio, using the control channel. If the registration is successful, the radio isregistered on the system and now can receive and transmit; if the registration isnot successful, the radio will not operate on the system.

Any time that the radio is powered on and the user changes talk groups the radiowill tell the system the new talk group selection, and the system will confirm theselection. In this way, the system tracks the currently selected talk group for allradios registered on the system.

When the radio is switched off by the user, the radio transmits a message to thesystem controller telling the system to deregister the radio. The radio then willwait for an acknowledgment from the system before actually powering off.

Talk group CallWhen a radio user wishes to transmit on a talk group, he/she presses the PTTswitch, just as with a conventional radio. The radio then sends the trunkingsystem a data burst request to transmit, using the control channel.

The trunking system checks to see if the requested talk group is free and if thereare available voice traffic repeaters. If these are true, then the system assigns avoice traffic repeater to the call and instructs all radios with the talk groupselected to change frequencies to the voice traffic repeater frequency.

The system also sends a message to the requesting radio telling it that it mayproceed with its transmission. This causes the users radio to play a tonesequence (typically three short beeps) to tell the radio user that he/she mayproceed with the transmission. The radios transmission is received by the voicetraffic repeater and retransmitted to the other radios on the frequency.

If the there are no voice traffic repeaters available for the call, the system willplace the request in a busy queue in order of priority, send a busy message tothe requesting radio and wait a short time for resources to become available. Ifthe resources become available, the transmission proceeds. If the resources do

not become available before the wait time expires, the system transmits amessage to the requesting radio telling it that the request failed. The radio willplay a tone (commonly called a bonk ) to the user indicating the failure . When aradio on a trunked system moves out of range of the system, it will emit a longtone indicating it is not available on the system. It is important for the user torecognize communications is compromised and know to take action to re-establish communications.


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Call DisconnectionWhen the transmitting user is finished with the transmission he/she will releasethe PTT switch. This causes the radio to send a message on the control channeltelling the system that it can release the resources assigned to the transmission.

Depending on the configuration of the talk group, the system either waits a fewseconds for additional transmission requests before releasing the resources, or itreleases the resources immediately. Once the timeout is reached, the systemtells all radios on the talk group to change channels to the control channel andreleases the voice traffic repeater for use for other requests.

If another request is received before the resources are released, then the systemimmediately grants the requesting radios transmission request and does notneed to tell the other radios to switch frequencies.

INCIDENT COMMUNICATIONS SUPPORT

Department CapabilitiesSeparate from our standard radio equipment, the Fire Communications andDispatch Support Section and OCD have access to tools and apparatus that willaide in the advent of a large scale incident to assist with and resolvecommunications shortfalls. This ancillary equipment includes the following.

1. Portable 800 MHz repeater systems.2. Portable cross band link system.3. Interoperability vehicles.4. Broadband (Internet) connectivity.5. Cellular phone amplifiers and repeater systems.6. Radio, battery and charger caches (VHF, UHF, 700/800 MHz)7. Mobile repeater vehicles with cross band capability.

Portable Repeaters The Department has a supply of portable 800 MHz repeaters which can beplaced by trained and qualified members to resolve radio coverage in areaswhich may have compromised coverage. A classis problem area for the LAFDis the Kirkwood Bowl area in Battalion 5. Fire Communications personnel havepreplanned sites for known problem areas in the city (Figure 18 ).


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Figure 19

Portable Cross Bank Links Portable cross bank links enable thelinking of different radio bands into acommon system. For example; avoice radio message transmitted on800 MHz can be received by thecross bank link and then retransmittedon UHF or VHF as desired. Thiswould also occur vice versa, a UHF orVHF voice radio message would belinked and retransmit on 800 MHz toprovide for a common communicationlink with outside agencies. Portablelinks look exactly like a portable

repeater; it is the internal workingsthat vary.

Interoperability VehiclesThe Department has two radio interoperability vehicles. Radio Interoperabilityvehicle 100 RI-100 and Radio Interoperability vehicle 200 RI-200 (Figure 19 ).Essentially, the radio interoperability vehicles are a grand version of the portablerepeaters with much more capability. Thus, they are much more complicatedand require more experience and extensive training to operate.

RI-100 and RI-200have the ability to linkchannels in differentfrequency bands. For

example, in a large-scale incident whereLAFD members wereworking with an outsideagency such asLACoFD,communication couldprove to be difficult.

Figure 18


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LAFDs tactical channels are in the 800 MHz range while LACoFDs tacticalchannels are in the VHF range. The interoperability vehicles have the ability tolink a LAFD TAC channel with a LACoFD TAC Channel.

When a signal is transmitted by a LAFD radio the RI vehicle will convert the 800MHz signal to a VHF signal that can be received by the LACoFDs radio . Thiswill allow the two agencies to communicate using their own familiar radios.

OCD also has special radio capabilities for mutual aid purposes. This includesradios on the fire mutual aid white channel and the three primary LACoFD UHFBluedispatch channels. OCD can also access channels on the State Fire Net,which has repeaters throughout the state for interdepartmental coordination, andfor communications with the State Office of Emergency Services (OES).

Other channels available at OCD are HEAR 1 and HEAR 2 (Hospital Emergency

Administrative Radio) for coordination with hospitals.

The City Civil Defense channel available at OCD is used in disaster operations tocontact the Mayor, City Council and their staffs as well as other persons with keypositions in disaster operations and for coordination with dispatch centersmaintained by other City departments.

Additionally, OCD has the capability to activate the Mt. Lukens back up radiosystem as well as link our 800 MHz radio system to the City Wide Trunked RadioSystem or EDACS system as well.

Broadband Connectivity.The Department has the ability toprovide Internet connectivity toassist in incident managementand information. Thisconnectivity can be establishedvia broadband (wireless card) orthrough satellite connection.

Additionally, secure local wirelessnetworks can be established to

enable a larger number of users(Figure 20 ).

Figure 20


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Interoperability This definition of interoperability is taken from the DHS SAFECOM project:

In general, interoperability refers to the ability of emergency responders towork seamlessly with other systems or products without any special effort.Wireless communications interoperability specifically refers to the ability ofemergency response officials to share information via voice and data signalson demand, in real time, when needed, and as authorized.

Day-to-DayInteroperability efforts are generally driven by the need to meet day-to-dayoperational requirements. Since September 11, 2001, there has been significantattention to expand interoperability past the day-to-day needs of a public safetyagency to address extraordinary events and incidents.

Interoperability is required and necessary in todays world . Where and how it

happens is based on a logical analysis of operational practices andrequirements.

Almost all fire departments have interoperability with other fire departments inCalifornia. Interoperability between agencies in the same discipline is intra-discipline interoperability. Inter-discipline interoperability is between differentdisciplines.

Intra-discipline interoperability is the easiest to achieve, since there is a commonlanguage, terminology, and tactical objectives. Inter-discipline interoperabilitymay not share common terminology or have the same tactical objectives.

A prime example is when the LAPD responds to a brush fire to assist withevacuation, when the LAFD responds on a reported shooting. Each discipline(LAFD/LAPD) has very different tactical objectives. As the fire responders fightthe fire using the common language of the fire service, this terminology may notbe understood by the law enforcement component. Knowing when to talk andwhen not to talk becomes a safety issue. In these situations interoperability mayrequire face-to-face coordination with the Command element.

Large Incidents As incidents grow, interoperability is planned for in the Incident Commandstructure. When developing interoperable Command structures, manyinteroperability tools may be employed. Technical staff plays a pivotal role inproviding technology tools to meet the operational requirements.

The use of a Communications Officer at major incidents and a CommunicationsUnit Leader is part of the National Incident Management System (NIMS)Command structure.


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Communications Unit Leaders in the NIMS Command structure provide a centralpoint of contact to develop a communications plan (ICS 205 ) to meet theinteroperability needs on a large incident.

When developing interoperable communications systems, determining thenumber of channels needed to support the incident must be a consideration. It isalways important to account for the amount of radio traffic on a channel.

Shared or patched channels can be used when there are common tacticalobjectives. Before patching channels or using gateways that essentially tiechannels together, the amount of traffic on each channel must be a considered.If both of the channels are near saturation, the patch or gateway will makecommunications nearly impossible.

Many technologies are available to achieve interoperability, and often the

simplest solutions are overlooked in favor of complex technological solutions.The simple solutions usually are the quickest to implement and easiest tounderstand. In some instances, face-to-face communications may provide thedesired level of interoperability, while in other cases other methods may benecessary.

Strike Team OperationsIt is important for all members to understand that the LAFD is licensed to use ourFCC assigned frequencies specifically within the geographic boundaries of theCity of Los Angeles and the immediate vicinity. Use outside the City limits isauthorized, and it can in fact be dangerous.

The frequencies assigned to the LAFD by the FCC are used by other publicsafety agencies throughout the state as well as through out the country, and theirspecific use may not be limited to voice communications. These frequenciesmay also be utilized for other purposes such as controlling electrical grids, watersystems and other radio networks.

The use of our assigned frequencies outside the City of Los Angeles may havecatastrophic results. There is real potential (especially as you venture furtherfrom Los Angeles) that use of our radios on our frequencies could inadvertentlyactivate, or deactivate systems that would normally be isolated from our systemby distance. There is no practical method to know in the field what or wherethese conflicts exist, therefore it is incumbent on members to adhere to incidentcommunications plans or use national or statewide interoperability channelswhen traveling or working outside the immediate area of Los Angeles.

The following state or national interoperability channels are recommended fortravel, or tactical operations use outside the immediate area of Los Angeles.
http://localhost/var/www/apps/conversion/tmp/scratch_6/Hyperlinks/ics205.pdfhttp://localhost/var/www/apps/conversion/tmp/scratch_6/Hyperlinks/ics205.pdfhttp://localhost/var/www/apps/conversion/tmp/scratch_6/Hyperlinks/ics205.pdfhttp://localhost/var/www/apps/conversion/tmp/scratch_6/Hyperlinks/ics205.pdf


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1. INTL FIREMARS (Fire Mutual Aid Radio System) in the 800 MHz band(red) radio. Use in simplex or direct mode of opera tion.

2. CESRS (California Emergency Services Radio System) in the VHF-100MHz band (white) radio.

Radio, battery and charger caches (VHF, UHF, 700/800 MHz)The Department currently usesthe Motorola IMPRESbatteries and charger systemsfor its portable radios. Thissmart energy systemau

lafd radio comm manual jan11

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