Codan Radio Transportable Radio Systems User Manual

TRANSPORTABLE

RADIO SYSTEMS

USER GUIDE

Table of Contents

CONTENTSCONTENTS

1. INTRODUCTION

1.1

1.2

1.3

1.4

1.5

1.6

2. SECTION 2 –

2.1

2.1.1

2.1.2

2.2

2.3

2.3.1

2.3.2

2.4

2.5

2.6

2.6.1

2.6.2

2.6.3

2.6.4

2.6.5

2.7

2.8

3. SECTION 3 –

ABOUT CODAN......................................................................................................................................................................... Page 4

INTENDED AUDIENCE.............................................................................................................................................................. Page 4

HOW THIS GUIDE WORKS..................................................................................................................................................... Page 5

PURPOSE.................................................................................................................................................................................... Page 5

TYPICAL APPLICATIONS........................................................................................................................................................... Page 6

BENEFITS.................................................................................................................................................................................... Page 6

REPEATER BASICS

WHAT IS A REPEATER?.............................................................................................................................................................. Page 7

Simplex Communications................................................................................................................................................... Page 8

Duplex Communications.................................................................................................................................................... Page 8

HOW DOES A REPEATER WORK?............................................................................................................................................ Page 9

OTHER TYPES OF REPEATERS.................................................................................................................................................. Page 9

Bi-Direc tional Ampliﬁ er (BDA)............................................................................................................................................ Page 9

Vehicular Repeater............................................................................................................................................................. Page 10

BA SE STATIO NS....................................................................................................................................................................... Page 10

BENEFITS OF A TRANSPORTABLE RADIO............................................................................................................................ Page 10

COMPONENTS OF A TRANSPORTABLE RADIO.................................................................................................................. Page 11

Transmitters and Receivers (TX/RX)............................................................................................................................... Page 11

Duplexers............................................................................................................................................................................ Page 12

Antenna............................................................................................................................................................................... Page 13

Enclosure............................................................................................................................................................................. Page 14

Power Supply...................................................................................................................................................................... Page 14

SUMMARY OF REQUIREMENTS........................................................................................................................................... Page 15

THE TRADE-OFFS OF A PRACTICAL SOLUTION THAT MEETS YOUR NEEDS................................................................. Page 15

REAL WORLD PROBLEMS AND THEIR SOLUTIONS

3.1 NO COVERAGE AREA.............................................................................................................................................................Page 16

3.1.1

3.1.2

3.1.3

3.1.4

3.1.5

3.1.6

3.1 .7

3.1.8

3.1.9

3.2

3.3

3.3.1

3.3.2

3.3.3

3.3.4

Temporary Communications during a Forest Fire....................................................................................................... Page 17

Forest Fire Fighting – Ground to Air Communications................................................................................................Page 17

Search and Rescue in a remote area.............................................................................................................................. Page 18

Communications for Natural Resource Exploration.................................................................................................... Page 19

Scientiﬁ c Research in the Antarctic............................................................................................................................... Page 20

Vehicle Accident in a Valley that has Poor or Inadequate Coverage....................................................................... Page 21

Multi Agency Interoperability – Columbine, Colorado............................................................................................... Page 22

Multi-Agency Interoperability – Alameda County...................................................................................................... Page 22

Coverage in Buildings and Tunnels................................................................................................................................ Page 23

EXISTING INFRASTRUCTURE FAILURES............................................................................................................................. Page 24

SPECIAL APPLICATIONS........................................................................................................................................................ Page 25

Secure Undercover Operations........................................................................................................................................ Page 25

Forward Observer/Sniper Communications................................................................................................................. Page 26

Diplomatic Security........................................................................................................................................................... Page 27

Customs Inspection on a Vessel...................................................................................................................................... Page 28

4. SECTION 4 – THE “WORKING” TRANSPORTABLE RADIO

4.1

4.1.1

4.1.2

4.1.3

4.2

4.2.1

4.2.2

4.2.3

4.2.4

4.3

4.3.1

4.3.2

4.3.3

4.3.4

4.3.5

4.3.6

4.3.7

4.3.8

4.3.9

4.4

4.4.1

4.4.2

4.4.3

4.5

4.5.1

4.5.2

4.5.3

4.6

4.6.1

4.6.2

4.6.3

4.6.4

4.7

4.7.1

4.7.2

4.8

FEATURES................................................................................................................................................................................Page 29

Analog vs. P25..................................................................................................................................................................................... Page 29

Encryption........................................................................................................................................................................................... Page 29

Conventional or Trunked Channels............................................................................................................................................ Page 30

TRANSMITTER & RECEIVER (TX/RX)................................................................................................................................................ Page 30

Transmitter.......................................................................................................................................................................................... Page 30

Receiver................................................................................................................................................................................................. Page 30

Transceivers........................................................................................................................................................................................ Page 30

Frequency Bands............................................................................................................................................................................... Page 31

CALCULATING SYSTEM GAIN AND RANGE................................................................................................................................... Page 32

Transmitter Gains.............................................................................................................................................................................. Page 32

Receiver Sensitivity........................................................................................................................................................................... Page 32

Antenna Gains................................................................................................................................................................................... Pag e 32

Duplexers............................................................................................................................................................................................. Page 32

Cable Losses........................................................................................................................................................................................ Page 32

Free Space Loss................................................................................................................................................................................... Page 33

Obstruction Losses............................................................................................................................................................................ Page 33

Fade Margin........................................................................................................................................................................................ Page 34

Path Calculation Worksheet......................................................................................................................................................... P age 34

DUPLEXERS.............................................................................................................................................................................................. Page 35

Isolation............................................................................................................................................................................................... Page 35

How do I provide Isolation to the Repeater?............................................................................................................................ Page 36

Duplexer Characteristics................................................................................................................................................................ Page 37

ANTENNAS............................................................................................................................................................................................... Page 39

Radiation Patterns and Types........................................................................................................................................................ Page 39

Antenna Size and Characteristics................................................................................................................................................ Page 40

Practical Considerations for your Antenna............................................................................................................................... Page 41

ENCLOSURES – CHOOSING THE RIGHT CASE.............................................................................................................................. Page 42

Open/Closed Lid Operation........................................................................................................................................................... Page 42

Case Selection..................................................................................................................................................................................... Page 43

Weight................................................................................................................................................................................................... Page 44

Case Size Selection............................................................................................................................................................................ Page 45

POWER SUPPLIES.................................................................................................................................................................................... Page 46

AC............................................................................................................................................................................................................ Page 46

DC........................................................................................................................................................................................................... Page 47

OPERATION AND MAINTENANCE................................................................................................................................................... Page 49

5. APPENDIX — REFERENCES

5.1

5.2

5.3

GLOSSARY................................................................................................................................................................................................. Page 50

REFERENCE DOCUMENTS.................................................................................................................................................................. Page 51

TRANSPORTABLE RADIO RFQ SHEET.............................................................................................................................................. Page 52

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PAGE 3PAGE 2

1. Introduction

1.3 How this Guide Works

1.1 About Codan

For the past 50 years Codan has provided customers worldwide with highly reliable Base Stations and Repeaters that are designed for robust operation in rugged environments, extreme temperature conditions and applications where low current consumption is a key requirement (solar, wind or battery powered).

Codan has been a pioneering member of the P25 Digital standard for radio system interoperability between emergency response governmental organizations, providing enhanced functionality and encryption. Our products operate between 29–869 MHz and are available in a variety of Base Station and Repeater conﬁ gurations for two-way voice and mobile data applications.

Our self-servicing customers range from Forestry and National Park services through Police and Fire departments and on to Utility and Transportation groups. Our products have been deployed in every imaginable situation from the Antarctic to Hawaiian mountaintops, enabling respondents to Forest Fires, Ground Zero rescue and routine patrols.

Codan is an industry leader in Analog and P25 radio systems design. We offer modular rack mounted Base Stations and Repeaters, as well as a family of transportable solutions capable of operating in the following bands:

• VHF FM

• UHF (380–520 MHz)

• 700 MHz

• 800 MHz

1.2 Intended Audience

This guide has been created to introduce non-technical personnel and end-users to information that will allow them to make the best choice in choosing a Transportable Communications Solution that is tailored to the emergency management or mutual aid requirements.

In preparing this guide, we recognized that ﬁ rst responders have more than just their Transportable Radio system to think about on a daily basis. While this is all we think about at Codan, it is only one of a long list of items needed for a First Responders “tool-box”. Therefore, we have arranged this document into four key sections:

• Section One — Introduction

• Sections Two — Repeater & Base Station basics — If you only have time for an overview to the key components you

need to address in helping design your Transportable Radio — This is the most important section.

• Section Three — Real World communications problems that we have helped solve at Codan using a variety of

Transportable Radio solutions. Someone may have already solved the very problem that caused you to start reading this guide in the ﬁ rst place...

• Section Four — This is a technical discussion of all the key components found in Section Two. If you would like to

have a better understanding of the “whys” and “hows” of a particular component of your system, this section will give you everything you need.

1.4 Purpose

When disasters strike, it usually happens at the worst time, in the worst location and somewhere that no longer has communications. Transportable Radio Systems support portable and temporary communication solutions that can be quickly deployed with minimal complexity.

A Transportable Radio such as the unit shown to the right may be a standard Land Mobile Radio (LMR) radio repeater specially packaged in a briefcase for portability with all the accessories required to instantly create a local repeater site. Capable of interfacing to First Responders’ handsets and mobiles, it creates a relay between First Responders and also links back to existing infrastructure. Transportable Radios are available for VHF, UHF and 700/800 MHz operation in either analog or digital P25 modes and can support cross banding between bands to enable different agencies to communicate together. Optional HF or Satellite interfaces enable communications to remote locations should existing infrastructure be damaged or unavailable.

Codan has a long history of making customized Transportable Radio solutions for its various customers and their many unique requirements. We have learnt over the years that each customer has a combination of particular requirements that need to be met to make sure their system is going to be successful in as many of their expected scenarios as possible.

You will ﬁ nd that as you work through this guide, there will be a number of choices you need to make about the requirements for your Transportable Radio System, and that each choice has a combination of trade-offs that must be understood. We hope this guide will allow you to make the best possible educated decision as to the features of your Transportable Radio System and the trade-offs that come with it.

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Packaging options such as high visibility waterproof cases are available for outdoor applications (forest ﬁ re ﬁ ghting) where the ability to work in any weather condition for extended periods is required. For tactical applications a Briefcase Repeater (as shown below) provides a compact, lightweight, package offering ease of deployment by one person. Both packages can provide quick connect AC or DC power and Antenna connectors along with battery backup, duplexers, antenna masts and trickle chargers allowing any ﬁ rst responder to setup and operate the radio system.

ET-4 Transportable Radio

Rugged

Metal

Storage

container

In-line

wheels

ET-4 Polyethylene

Briefcase

Power supply,

battery backup,

speaker

Soft grip

handle

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Press and

Pull latches

Radio with

30 W Power

Ampliﬁ er

Telescoping

Pull handle

PAGE 5PAGE 4

1.5 Typical Applications

2. Section 2 — Repeater Basics

Applications for Transportable Radios are as diverse as the First Responder agencies (Police, Fire, Ambulance, Search and Rescue, Civil Defense, Forest Fire Fighters, Reconstruction and Recovery operations) using them. In fact it is hard to imagine a First Responder group that doesn’t need a Transportable Radio System.

• Forest Fires — Transportable Radios are deployed during Forest Fire season providing on-site communications. The

repeater may be conﬁ gured with cross banding capabilities to facilitate communications with spotter helicopters or water bombers ﬁ ghting the ﬁ res.

• Natural Disasters — Hurricanes, earthquakes and tsunamis can destroy ﬁ xed infrastructure (as was the case with

Hurricane Katrina in New Orleans), Transportable Radio Systems provide temporary communications to on-site ﬁ rst responders and also provide additional communications infrastructure for ﬁ rst responders that may be coming into the region to assist.

• Multiagency Tactical response — require tactical or covert communications with encryption. Radio equipment

packaged in a compact, low visibility black suitcase will not be obvious to the public or allude to the nature of the equipment being used.

• Search and Rescue — Search and Rescue applications need communications that may not normally be served by

the existing ﬁ xed infrastructure. A Transportable Radio provides localized communications in a collapsed building recovery zone, tunnel or a rural region. Optional Satellite or radio links may be used to link back to an existing network.

1.6 Benefits

Transportable Radios provide instant communications anywhere, anytime. Able to be set up in a matter of minutes, they provide ﬁ rst responder agencies with an instant solution to communications challenges. Key beneﬁ ts include:

2.1 What is a repeater?

Radio signals operate over line-of-sight paths. This implies that you must be able to see the radio with which you wish to communicate. Actually, contact between radios slightly beyond line-of- sight distances is often possible, owing to reﬂ ection or refraction of the radio waves. Physical restrictions of signal paths between radio users (such as mountains or buildings) can disrupt system operation.

The diagram below on the left shows the line-of-sight signal paths between the portables and from the portables to the base station at the ofﬁ ce. At the far right, note the blocked signal path between the mobile and the ofﬁ ce caused by the hill which prevents the mobile from communicating.

Limited communication due to obstructions

To extend coverage, a radio repeater is required. A repeater is nothing more than a radio or combination of radios connected in such a way that it simply passes on or “repeats” anything that it hears. In the diagram below the repeater enables all radios to communicate together.

• Consumes minimal power allowing operation from solar panels or batteries

• Intended for all weather and operational conditions (including high altitudes)

• Capable of operation in any frequency bands

• Supports cross banding between frequencies

• Compact and easy to deploy by a single person

• Analog or Digital P25 (Clear or Secure)

• Waterproof, Shockproof, Vibration proof

• Rapidly deployable

• Reliable

Repeater installed to enable communications

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PAGE 7PAGE 6

2.1.1 Simplex Communications

2.2 How does a Repeater Work?

To understand how a repeater actually works, it is best to ﬁ rst start with portable to portable communications. In this scenario, communications is on a single common frequency from one user’s radio to another user’s radio directly. The transmitting radio is transmitting its signal on a single frequency, which we will refer to as F1. While it is transmitting on F1, only the transmitter is connected to the antenna, and therefore it cannot receive at the same time.

On the other end of this scenario is the receiving radio, whose receiver is connected to its antenna (the default scenario for any radio), and is always listening to F1 as long as its user does not try to make their own transmission.

Portable to Portable

Communications

This direct method of communication is referred to as Simplex Communication. A single frequency is used to allow for single direction communications. Users of this system can talk back and forth between each other, but they must take turns talking. This is how all standard portable and mobile subscriber radios work.

A repeater receives a signal at a particular location, and at the exact same time re-transmits that signal, at a much higher strength, to the immediate vicinity. This is very handy for getting a signal to go around or over large objects such as mountains, or to take a weak signal and boost it for penetration into a building or other structures.

To do this a repeater makes use of duplex communications. A repeater requires a pair of frequencies; a Receive Frequency (F1 for example) and a separate Transmit Frequency (in this case, F2). When the repeater receives a signal on F1, it simultaneously transmits the received signal on F2. All of the radio users in the coverage area of the repeater that are listening to F2 will hear the signal that was originally sent out on F1.

For all users in the ﬁ eld who want to communicate through the repeater, they will transmit on their portable radios using F1 and receive on F2. While the portable radios in the ﬁ eld are still making use of Simplex Communications, the repeater is making use of Duplex Communications to provide the added coverage.

2.1.2 Duplex Communications

Duplex Communications on the other hand allow for simultaneous transmitting and receiving of two different signals. This scenario requires 2 distinct frequencies, and obviously a radio that is capable of both transmitting and receiving at the same time. While this is not how portable and mobile radios work, this is the general concept behind the operation of a repeater.

Duplex Communications

VHF F

Repeater Site

VHF F

Repeater System

2.3 Other Types of Repeaters

2.3.1 Bi-Directional Amplifier (BDA)

A Bi-Directional Ampliﬁ er (BDA) is a common solution for in-building or tunnel communications. A Bi-Directional Ampliﬁ er system consists of one or more ampliﬁ ers located inside the conﬁ ned environment and in turn connected to an external antenna network. The external antenna, usually located on the roof of the building, or mouth of the tunnel, receives the signal coming from the external radio site. The BDA then ampliﬁ es the signal and retransmits it into the building or tunnel. A subscriber unit within the building can use the BDA to extend their portable radio coverage and communicate with the external system. The BDA listens for incoming trafﬁ c inside the conﬁ ned space, ampliﬁ es it and retransmits it to the external system, hence bi-directional. A BDA can be relatively inexpensive, however, the supporting infrastructure of cabling, antennas, ﬁ lters and power supplies quickly add to the total installed cost. Furthermore, unless BDAs are adjusted correctly, they can create interference issues with themselves, with other BDAs, or with the existing radio system.

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PAGE 9PAGE 8

2.3.2 Vehicular Repeater

2.6 Components of a Transportable Radio

A vehicular repeater is a specialized radio repeater mounted in a vehicle that is used in conjunction with a mobile radio to effectively expand the range of a portable radio in the ﬁ eld. To illustrate this concept, an ofﬁ cer leaves his vehicle and begins transmitting on his portable radio. The 3–5 Watt portable radio signal is boosted through the vehicular repeater, thus enabling transmission at much greater distances. For in building or tunnel scenarios, the vehicular repeater can improve the local communications in an emergency response. The vehicular repeater typically is not limited by a power source and is highly mobile. However, it is limited by its ability to be moved from location to location and used in conﬁ ned or remote environments.

2.4 Base Stations

Base Station Radio System

Base station radio systems are used to communicate between a dispatch/command center and mobiles or portable-equipped radio users in the ﬁ eld. Base stations typically need to communicate on multiple channels and frequently the radio itself needs to be physically located at a remote location so as to provide better radio coverage.

Digital base station radios can support either secure or clear digital mode operation (encrypted or non- encrypted) using AES 256-bit or DES-OFB 64-bit encryption modules compliant to the security requirements of FIPS 140-2. Digital base stations have the ability to automatically detect and differentiate between analog and digital as well as encrypted or non-encrypted signals.

The following diagram and subsections overview the components of a Transportable Radio. Comprehensive details on each component are provided in Chapter 4.

Common Layout of a Transportable

Repeater consists of: –Tx, Rx and Ampliﬁ er – See section 2.6.1 –Duplexer - See section 2.6.2

Enclosure for Repeater

Repeater System

Power Supplies – See section 2.6.5

Solar Panel

Battery

Antennas – See section 2.6.3

A local or wide area network can be used to link the dispatcher/command center and the base station site. Using the P25 Digital Fixed Station Interface (DFSI) standard, an all digital (optionally encrypted) communication path can be created from the portable to the dispatch center connected to the base station.

2.5 Benefits of a Transportable Radio

Normally, a repeater system is a ﬁ xed installation used in combination with base stations and other equipment – collectively known as “infrastructure”. One or more repeaters and base stations can be used to provide reliable wide area coverage for the users in the ﬁ eld. However, due to the physical limitations of installing “infrastructure equipment” permanently in locations that are appropriate for housing communications equipment (radio towers, building tops, mountains, etc.) there will always be areas that are not adequately covered. This may be due to being beyond the coverage area of the system or working inside a large building that provides challenges for signal penetration (very common in most urban areas).

In these areas of little or no radio coverage, a Transportable Radio can be very beneﬁ cial in bringing the coverage strengths found in a normally ﬁ xed piece of infrastructure equipment to the scene of operations. By providing the users on-scene with a local repeater, the communications between those ﬁ rst responders on-scene can be very effective. Whether the Transportable Radio is a small, low-power, tactical unit or a large, high-power, multi-agency/ multi-band system providing interoperability, a well planned Transportable Radio system will be a very effective tool for all users that are operating in an area that typically would not have any radio coverage at all.

Enclosures – See section 2.6.4

2.6.1 Transmitters and Receivers (TX/RX)

The transmitter (TX) and receiver (RX) are the key components of a Transportable Radio system. A repeater, whether permanently installed infrastructure equipment or a Transportable Radio, will always have a Transmitter and Receiver that are separate from each other. Further to this, the Transmitter and Receiver will each have their own frequency. A repeater may not have the same Transmit and Receive frequency.

The Transmitter in a repeater system is designed to be capable of transmitting on only the desired frequency and not broadcast excessive noise and signals on other frequencies that may be operating in the area. Typically a repeater transmitter is higher power than a Portable or Mobile Radio, but it does not have to be. Remember that the location of the repeater and its antenna is as important as the radiated power of the repeater itself. Optional an ampliﬁ er may be added to the transmitter to provide higher output power. For transportable radios this is typically less than 50 Watts due to proximity of the users and current consumption.

The Receiver in a repeater system is designed to be highly sensitive to low signal strengths so that users in the ﬁ eld with low power radio equipment such as portable radios, can communicate with the repeater. However, the repeater receiver must also be capable of rejecting all the other signals that it may hear on adjacent channels. This is what makes a repeater receiver different from a portable or mobile radio.

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PAGE 11PAGE 10

2.6.1.1 Transceivers

2.6.3 Antenna

Transportable Radios can also be built from transceivers which are the same type of radio used in a mobile or portable. A transceiver as its name implies (Transmitter/Receiver = Transceiver) is a radio that combines the transmitter and receiver circuitry together. Compared to a distinct transmitter and receiver pair, a transceiver is a simpler device offering the beneﬁ ts of smaller size, lower cost and lower current consumption. Hence the reason all portables and mobiles are transceiver designs. The tradeoff compared with a distinct transmitter/receiver pair is lower performance speciﬁ cations, lower reliability and having to replace the entire unit in the event of a failure.

2.6.2 Duplexers

As mentioned above, a repeater will always have distinct Transmit and Receive frequencies. Even though the receiver is designed to ignore signals that are not on its tuned frequency, the transmitter in the repeater will be transmitting a relatively high strength signal at the same time that the receiver is receiving its signal. To prevent the transmitter from interfering with the receiver during this “repeat” operation, we need to protect the receiver, or isolate it from the transmitter.

One way to isolate the Receiver from the Transmitter is to use two separate antennas and place them some distance apart. How far the antennas need to be away from each other is dependent on the frequency of operation, the power of the Transmitter and the proximity of the actual Transmit and Receive frequencies. Make no mistake, typically these two antennas need to be quite a distance apart (tens of meters) in either vertical or horizontal separation.

There is a much easier way to protect the receiver other than running hundreds of feet of cable in opposite directions! A duplexer can be used to ﬁ lter out the transmitter frequency before the receiver sees it. A duplexer is a radio frequency ﬁ lter that allows you to connect both the Transmitter and Receiver to a single antenna. The portion that is connected to the Transmitter will only allow the Transmitters frequency to pass. The portion connected to the receiver will only allow the receiver frequency to pass. This way the high strength signal created by the Transmitter cannot be fed back into the Receiver and cause interference or damage the receiver with too much RF power. From a Transportable Radio standpoint, the duplexer approach makes things much simpler since only a single antenna needs to be deployed on-scene and it facilitates a compact package.

Duplexer enabling connection of both a transmitter and a reciever to a single antenna

TX — UHF F RX —UHF F

451.775 MHz

456.775 MHz

TX — UHF F

RX — UHF F

Repeater Site

451.775 MHz

456.775 MHz

Whether you opt for the dual-antenna deployment or the more commonly used single antenna with a duplexer, pay careful attention in selecting the right antenna for your application. The antenna receives the signal from the users in the ﬁ eld and sends out the new repeated signal from the Transportable Radio transmitter.

Beam Antenna

Typical Horizontal

Radiation Pattern for

Vertical Polarization

There are a number of considerations in selecting an antenna:

• Gain – Antennas can provide gain. This can reduce the amount of RF power needed by the transmitter or it can

increase the coverage range. In Section 4.2.9 we show that for a UHF repeater with a 5 Watt output the expected coverage range is on the order of 10 kms. To double the coverage distance you need a gain of 6 db or 4 times the RF output power!

• Radiation Pattern – antennas can be made to direct the coverage in a speciﬁ c pattern. For example a Yagi antenna

(shown above) will direct most of the signal to the “front” with little or no signal delivered to the sides or back of the antenna. An Omni directional antenna will radiate in all directions

• Bandwidth – The range of frequencies that the antenna is capable of covering.

• Antenna type – antennas are available in an almost unlimited number of shapes and styles. Common examples include:

The “Rubber Duck” – a small but convenient antenna, commonly found on portable radios. It has poor transmit

and receive speciﬁ cations but is the easiest to deploy.

Magnetic Mount vehicle antenna – Assuming a metal surface is handy for mounting this antenna such as the

roof of a car, this can be a convenient antenna for rapid deployment. Has better transmit and receive characteristics than the Rubber Duck.

Yagi antenna – requires some form of mast mounting but offers good gain characteristics and is also directional.

Stealth Panel antennas – are speciﬁ cally designed to be disguised in a case or look like something other then

a radio antenna.

(360°).

Duplexer

TX — UHF F

RX — UHF F

451.775 MHz

456.775 MHz

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UHF Repeater

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PAGE 13PAGE 12

2.6.4 Enclosure

2.7 Summary of Requirements

Depending on the nature of the Transportable Radio deployment the enclosure can be critical to the success or failure of your system. If the enclosure is not sealed to the outside world, and the deployment will be in harsh weather conditions with high levels of rain and dust exposure, then eventual failure of the system is likely.

There are a variety of enclosures available depending on your requirements:

• Aluminum Cases – These cases are very rugged and capable of air-tight ratings for the harshest of wet environ-

ments. These cases are also a good option for outdoor deployments such as forest ﬁ re ﬁ ghting or search and rescue. Pressure release valves enable the cases to be transported in airplanes without pressurization.

• Polyethylene Cases – Offer a wide selection of sizes (briefcases, suitcase) with options such as pull-out handles and

roller wheels. Ideal for sub-urban and urban deployments.

• Polyethylene Rack Mount Cases – Larger versions of the polyethylene suitcases. These cases typically have entire

racks inside for mounting large communications systems such as multi-agency/multi-band systems or Transportable Trunked systems with multiple channels. Typically they are for very heavy equipment and require more than one person to lift. Ideal for permanent mounting inside vehicles or mobile command centers.

Polyethylene Rack

Mount Case

Polyethylene Case

2.6.5 Power Supply

A transportable radio system is intended to provide radio coverage on a temporary basis in an area not normally served or to replace an existing radio site that has gone out of service. As such there are 4 key issues to keep in mind in selecting your Transportable Radio System:

• Features – What are the essential features the radio system must provide?

Will the radio be conventional or trunked? Number of channels required? Will it operate in analog, P25 digital, P25 digital encrypted mode or all? What frequency band(s) are you using? Desired coverage area and transmit power required?

• Ease of Deployment – Where will the system be set up?

Source of power? Setup time – minutes / hours? Total weight and size – number of people for setup? Type of transportation required (hand carried or in a helicopter)? Type of Enclosure — Outdoor / Indoor, Visible / Stealth?

• Operation – Who will set up and operate the system?

Level of training required? Linked to the existing radio network? Ease of repairing a failure? Can the system be reconﬁ gured?

• Affordability – What will the system cost over its operational life?

Initial cost? Power costs? Maintenance and service costs? Expected operational life?

The ﬁ nal critical part of the Transportable Radio is the power supply. An analysis of the possible deployment scenarios needs to be done prior to specifying the desired power source. Common power supplies used for Transportable Radios include:

• AC Power – very simple to connect to, just plug the repeater into the “wall” and turn it on. This is only appropriate

for some applications as even urban deployments can ﬁ nd a system with only AC power very limiting in where it can be deployed. Either that or get a very long extension cord…

• Generators – gas or diesel generators can be used. These offer either an AC or DC output. Capable of very high

output powers, the big issue here is supplying fuel.

• Battery Power (Internal or External) – Very simple to operate, just turn on the repeater. However internal batteries

mean the repeater is heavier and has a shorter run time since only small batteries can be used. By adding a second case to the repeater system, signiﬁ cant increases in run times can be achieved as the external battery can be much larger than its internal relative. However, a second case adds size and weight. Users of the system must always remember to recharge the batteries between uses and the repeater must be very efﬁ cient with its current draw.

• Solar Powered – By adding a solar panel to the repeater, it is possible to achieve extremely long run times. This is

very helpful for deployments that will be for an undetermined amount of time such as a Natural Disaster recovery or Forest Fire. This solution adds a third case to the deployment however and again the repeater needs to be very efﬁ cient with its current draw.

• Wind Generators – can provide power in remote locations for long periods of time as a supplement to solar and

battery systems.

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2.8 The trade-offs of a practical solution that meets your

The most important thing to remember when choosing the key features for your Transportable Radio as summarized above is that there are always trade-offs. For example, a system cannot be extremely small AND be high power at the same time. By going small the system cannot accommodate ampliﬁ ers or large power supplies.

needs

Priority Trade Off

Small Size

Easy to use

Maximum coverage/penetration

Multi-Channel

Multi-Band

Internal Battery

Long deployments

Low Power Output, single channel, few options

Few options, less ﬂ exible

High-power required, therefore large size

Requires large custom ﬁ lter or two antenna

Each band requires its own repeater and duplexer, therefore this system will be larger the more bands that are required

Weight, batteries are heavy

Additional power sources required such as battery banks or solar power

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3. Section 3 – Real world problems and their solutions

3.1.1 Temporary Communications during a Forest Fire

This section outlines some of the different scenarios in which a Transportable Radio is required and provides example deployments.

3.1 No coverage area

Transportable Radios are an obvious choice when communications are required in an area that is not served by the existing infrastructure. This could be:

a) A remote area where ﬁ re ﬁ ghters are dealing with a forest ﬁ re b) A search and rescue operation in a remote area beyond the coverage of the ﬁ xed infrastructure or in an urban area

where the infrastructure has failed

c) Oil/mineral exploration or scientiﬁ c research in a remote area with local communications for the exploration/

scientiﬁ c team and a satellite link back to head ofﬁ ce

d) Emergency response to a vehicle accident on a remote highway or valley with poor coverage from the existing

radio network

e) Expanded coverage and capacity during an emergency when many ﬁ rst responder agencies are participating on-site f) In building/tunnel dead zones during a ﬁ re, emergency or routine maintenance

As shown in the diagram below on the left, the upper handheld is obstructed from communicating with the ofﬁ ce due to the hills. If that handheld is a ﬁ rst responder dealing with any of the above scenarios then there is no communication back to the support center. A Transportable Radio strategically located at a high elevation can enable communications between the remote area and the support center as illustrated in the second diagram below on the right.

The British Columbia Ministry of Forestry and the US National Interagency Fire Center (NIFC) have developed Fire Repeaters that can be quickly deployed to temporarily enhance radio communications for ﬁ re ﬁ ghters, where coverage in the area is poor. They can be linked into the existing networks, or work as stand alone units.

The Fire Repeater (shown to the left below) consists of a radio repeater (receiver, transmitter, duplexer and magnetic mount antenna) in a high visibility all weather aluminum orange case, a 35 AH battery (in the silver box) and a solar panel (to charge the battery during the day). Combined with an antenna and mast an entire radio site can be quickly deployed by vehicle or helicopter to a hilltop to provide communications coverage during the response to a forest ﬁ re (as shown below right).

http://www.for.gov.bc.ca/his/radio/Overview/overview.htm

Limited communication due

to obstructions

Repeater installed to enable

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communications

3.1.2 Forest Fire Fighting – Ground-to-Air Communications

To facilitate the establishment of rapid communication links between ground base ﬁ re crews and supporting water bomber crews, a transportable Ground-to-Air crossband repeater is the ideal solution. A Ground-to-Air Crossband Repeater allows FM ground radios (VHF or UHF) to communicate with AM VHF airband radios. This is ideal for providing ground based ﬁ re ﬁ ghters or search and rescue crews with direct communication to supporting aircraft and helicopters. A Transportable Crossband Repeater system enables system interoperability by changing frequency bands between the two radio systems.

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+ 18 hidden pages

Codan Radio Transportable Radio Systems User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual