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Radio 101 for ESF #2 Webinar Presentation for ESF #2 2pm EST, Monday, February 28, 2011 Ross Merlin DHS Office of Emergency Communications 2/28/20111 The.

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Presentation on theme: "Radio 101 for ESF #2 Webinar Presentation for ESF #2 2pm EST, Monday, February 28, 2011 Ross Merlin DHS Office of Emergency Communications 2/28/20111 The."— Presentation transcript:

1 Radio 101 for ESF #2 Webinar Presentation for ESF #2 2pm EST, Monday, February 28, 2011 Ross Merlin DHS Office of Emergency Communications 2/28/20111 The author is a senior telecommunications specialist with the DHS Office of Emergency Communications. His Federal emergency communications experience includes disaster response with the National Disaster Medical System, FEMA wireless management, DHS spectrum management, and now the OEC Technical Assistance branch. He is the author of the National Interoperability Field Operations Guide (NIFOG). You may contact him via

2 Public Safety Radio Bands VHF-Low Band: 30 MHz to 50 MHz VHF-High: 138 MHz to 174 MHz UHF: 406 MHz to 512 MHz 700 MHz (new) 800 MHz 4.9 GHz (new) 2/28/20112

3 Can we talk? Most radios only operate in one band! – Multi-band radios are rare and expensive If Agency A uses VHF and Agency B uses UHF, they cant talk to each other unless they: – Use runners – Have face-to-face interoperability – co-locate at Command Post – Swap radios – Relay through dispatchers – Connect through a gateway 2/28/20113

4 Propagation & Band Characteristics VHF Low Band (30-50 MHz) – Best propagation in undeveloped and hilly terrain – Poor building penetration VHF High Band ( MHz) – Very good propagation in undeveloped and hilly terrain – Moderate building penetration UHF ( ; some areas or MHz; Federal Government MHz) – Good propagation in undeveloped and hilly terrain – Good building penetration 700/800 MHz – Poor propagation in undeveloped and hilly terrain – Very good building penetration 4.9 GHz – Microwave propagation used for short range (WiFi type) or point-to-point links 2/28/20114

5 Frequencies vs. Channels A frequency is a point in the radio spectrum – Part of what describes a channel A channel is a set of parameters that can include one or more frequencies, Continuous Tone Coded Squelch System (CTCSS) tones, bandwidth, modulation, name, etc. Example: VCALL10 is a channel with transmit and receive frequency MHz, transmit CTCSS tone of Hz, no receive CTCSS tone, bandwidth kHz 2/28/20115

6 Continuous Tone Coded Squelch System (CTCSS) Tones PL stands for Private Line, a Motorola trademark Other names include Code Guard, Tone Squelch, Call Guard, Channel Guard, Quiet Channel, Privacy Code, Sub-audible Tone, etc. Generic (vendor-neutral) term is CTCSS – Continuous Tone Coded Squelch System 2/28/20116

7 What Are CTCSS Tones Used For? CTCSS tones are used to MASK interference They DO NOT remove interference Useful for masking interference caused by computers, electronics, etc. Useful for masking interference from skip Should NOT be used to block out traffic from neighboring (nearby) departments – This is OK for taxis, etc., but not for public safety – Creates Hidden Interference problem – missed calls possible 2/28/20117

8 Radio Programming Programming a radio is not like programming a microwave oven Oven: Universal programming tool (fingertip) works with all brands. Graphic User Interface (touchpad) similar Radio: Every brand has their own tools: cables, adapters, software. No standard for frequency (MHz or kHz), CTCSS (frequency or code), Network Access Code (NAC) (hex or decimal), etc. 2/28/20118

9 Results of Improper CTCSS Programming If Radio 1 is set for transmit (TX) tone only and Radio 2 is set for transmit/receive (TX/RX), both radios will hear each other. Radio 1 will hear any interference on the channel If Radio 1 is set for TX tone only and Radio 2 is set for no tone, both radios will hear each other. Both radios will hear any interference on the channel If Radio 1 is set for TX/RX tone and Radio 2 is set for TX/RX tone, both radios will hear each other. If Radio 1 is set for TX/RX tone and Radio 2 is set for no tone, Radio 1 will not hear Radio 2. Radio 2 will hear Radio 1 ANY radio programmed with an incorrect TX tone will not be heard by radios using a RX tone, even though it can hear traffic from other radios 2/28/20119

10 Results of Improper Frequency Programming You can hear other stations but cant be heard You cant hear other stations but they can hear you You cant hear other stations or be heard You can hear other stations when they are close to you, but cant hear them when they are far away (via a repeater) You are transmitting on an unauthorized frequency, causing interference to a different radio system You are listening to a different radio system but think it is yours – you are very confused 2/28/201110

11 Simplex Very Reliable Limited Range Radio Channel uses 1 frequency 2/28/201111

12 Duplex Radio Channel using 2 frequencies: Frequency 1 to talk from radio A to radio B, and Frequency 2 to talk from radio B to radio A Each user must be line of sight with each other Examples: Cordless Telephone systems, which both parties can talk at the same time and listen at the same time. f1 f2 2/28/201112

13 Base Station – Height Improves Range Unit 1 Dispatch Center Unit 2 Unit 3 Unit 4 Some units dont hear transmission because of obstructions 2/28/201113

14 Base Station – Height Improves Range Unit 1 Dispatch Center Unit 2 Unit 3 Unit 4 Dispatcher relays message – heard by all units 2/28/

15 Remote Base Operation Unit 1 Unit 2 Unit 3 Unit 4 Dispatch Center Remote Link Microwave, Phone Line, etc. 2/28/201115

16 Conventional Repeater Receives a signal on one frequency and retransmits (repeats) it on another frequency Placed at a high location Increases range of portable and mobile radio communications Allows communication around obstructions (hills, valleys, etc.) User radios receive on the repeaters transmit frequency and transmit on the repeaters receive frequency 2/28/201116

17 f1 f2 f1 RX TX Conventional Repeater All units within range of repeater hear all transmissions through the repeater Unit 1 Unit 2 Unit 3 Unit 4 Dispatch Center f2 Repeater 2/28/201117

18 PD 2 PD 1 PD 3 PD 4 FD 1 FD 2 FD 3 PW 1 PW 2 PW 3 Conventional Systems When one user is talking, other users on that channel cannot talk, even though other repeaters in the area may be idle. Communicating Idle PD 3 cannot talk to PD 4 because PD 1 is using the repeater Public works repeater may be idle 90% of the time, which means that frequency is largely wasted 2/28/

19 Trunking Trunking is a method of combining repeaters at the same site (often multiple sites) to share frequencies among users Spectrally efficient Allows many more virtual channels (called talkgroups) than there actually are frequencies authorized to the system Computer controlled 2/28/201119

20 f1 f2 f1 RX TX Trunked System f4 f3 RX TX f6 f5 RX TX PD 1PD 2 Shared Repeater Bank PD 3 FD 1FD 2 f3 f4 Frequencies are dynamically assigned by system controller User radio may be on a different frequency every time it transmits Talkgroups are virtual channels Possible to have many more talkgroups than actual frequencies Statistically, not all talkgroups will be active at the same time System Controller 2/28/201120

21 Trunked System Operation User radios continuously monitor a dedicated control channel When a user wants to transmit, the users radio makes a request to the system controller If a repeater is available, the system controller temporarily assigns that repeater channel to the talkgroup making the request Transmitting users radio will give a talk beep, indicating that a repeater has successfully been assigned…then the user can talk All user radios monitoring that talkgroup automatically switch to the frequency of the assigned repeater and hear the transmission When the transmission is complete, all radios return to monitoring the control channel 2/28/201121

22 Multi-Site Systems Conventional – Repeaters on same output, different input – Linked repeaters on different frequencies – Remote Receive Sites Voting – Simulcasting Trunking – Roaming – Simulcasting 2/28/201122

23 Repeaters on same output frequency, different input frequency (or CTCSS tone) Users must manually change channel to different repeater depending on their physical location Only one repeater active at a time 2/28/201123

24 Repeaters on same output frequency, different input frequency (or CTCSS tone) Users must manually change channel to different repeater depending on their physical location Only one repeater active at a time 2/28/201124

25 Linked repeaters on different frequencies Users must manually change channel to different repeater depending on their physical location Link (microwave, phone line, etc.) Both repeaters active at the same time with same traffic, but on different frequencies 2/28/201125

26 Voting Receivers Users do not need to change channel depending on location. System (voter) automatically picks best receive tower site. Link (microwave, phone line, etc.) RX Only Site Voter Central Transmitter Voter (comparator) chooses best received signal and sends that signal to the transmitter 2/28/201126

27 Simulcasting Transmitters must be carefully synchronized to prevent interference in overlap areas Both repeaters transmit on the same frequency at the same time Link (microwave, phone line, etc.) 2/28/201127

28 Caller: The radio system is down. You: What kind of system? VHFUHF AnalogConventional Simplex Conventional Repeater* Trunking Repeater very rare rare for PS DigitalConventional Simplex Conventional Repeater Trunking Repeater * Single site? Voted receive sites? Linked repeaters? Simulcast? 2/28/201128

29 Possible Points of Failure User Radio – Untrained user – Trying to use beyond coverage area, or shielded by terrain – Loss of power (base station) or dead battery (hand-held) Repeater – Loss of commercial power, backup battery or generator fuel exhausted – Antenna failure (wind or ice damage) – Catastrophic site loss (tornado, fire, explosion) Link (T1 line, microwave link, etc.) – Loss of power – Antenna failure – Telco circuit outage (phone line, internet) 2/28/201129

30 Network Status In a telco or cellular telephone network there is a Network Operations Center (NOC) that knows the status of the network In Land Mobile Radio (LMR) there is no the network – Each radio system is independent – A statewide system or a trunked system may monitor the status of some components of just that system – No one place to go to learn status of all LMR systems Commercial Mobile Radio Service (CMRS) networks may have a NOC; most public safety radio systems not CMRS customers, they are government-owned LMR 2/28/201130

31 Limitations of the Technology Radios, without infrastructure, have a short effective range – line-of-sight Repeaters extend range, but require power Repeater systems and networks extend the coverage area, but increase complexity Trunked radio systems increase capacity, but are much more complicated and are not easily transportable 2/28/201131

32 Regulatory & Operational Limitations Users can not program radios – must be done by a technician (FCC Part 90; not so for NTIA). Some agencies radios are password protected - if their technician is not a first responder (and wont share the password) field programming not possible Rules are ambiguous and arcane; written for day-to-day operability and interoperability, not catastrophic disaster response All radio frequencies used by responders should be coordinated with Disaster Emergency Communications (DEC) Group Frequency Manager before use 2/28/201132

33 Programming Limitations Programming in the field, while under stress, is more likely to lead to errors Front-panel programming takes a lot of time Programming by computer takes time to setup the first time, then fast to program multiple radios with the same channels; model-specific hardware and software Cloning to program multiple radios is fast, but requires model- specific cloning cable and radio passwords Trunked radio system key needed to program radios, but seldom shared – system tech too busy to program key and freqs into visiting responders radios 2/28/201133

34 Problems You May Handle (1 of 3) Call from state/local (other than simple question) didnt come through state ESF #2 – Refer caller to state ESF #2 Call about radio/telephone/Internet in Joint Field Office (JFO) – Transfer call to JFO Logistics Section, Comm. Unit Question about radio frequencies/channels – Transfer to your Spectrum Manager (continued) 2/28/201134

35 Problems You May Handle (2 of 3) You didnt deploy your Spectrum Manager? – Shame on you! – Spectrum Manager needs to be among the first boots on the ground – once behind, can never catch up Fed/state/local or Private Voluntary Organizations (PVO)/Non-Governmental Organization (NGO) needs radios, needs help programming radios, needs help repairing/installing/acquiring antenna, needs temporary tower, needs WiFi, needs internet backhaul, satellite communications, repeaters, remote base stations, trunked radio system… – Get specifics, then task to DEC Group of ESF #2 2/28/201135

36 Problems You May Handle (3 of 3) Before you start taking calls, work out with DEC Group whether they want to handle generator issues at communications sites, or whether those calls go to ESF #12 (Energy) Offer to donate radios or comm-specific supplies, services, technicians – Track or transfer in accordance with JFO donations policy Broadcast station needs help (including generator) – Refer call to your FCC liaison 2/28/201136

37 Making Friends If FEMA installs equipment or an entire radio system for the locals, can the locals keep it? 2/28/ No. Non-consumable items purchased with Stafford Act funds will be recovered, refurbished, and re-used on a future disaster; or disposed of through normal US Government excess property procedures

38 Summary This radio stuff is complicated Get the right information on the first call FEMA can get it, whatever it is (if justifiable) Spectrum Managers – dont leave home without one 2/28/ Some of the material in this presentation was adapted from unications/RadioTrainingSlides Generic.ppt unications/RadioTrainingSlides Generic.ppt


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