Information Station Specialists is the best known source of travelers information stations, highway advisory radio, advisory signs and services needed to reach motorists with public service information. Learn more about Information Station Specialists.
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Glossary of Radio Terminology
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2X Signal Booster     

Option that offers up to double the efficiency/range of a Travelers Information Station’s antenna, allowing the transmitter to run at less wattage or allowing the signal to have additional the intensity at a given distance. Functions with upper-band (typically 1610-1700) antennas only. Recommended for federal government agencies that do not have a signal intensity limitations, also for any operator in a challenging environment that requires maximum signal intensity to cut through woods, buildings and obstructions. (Note: local government licensees must seek a waiver of FCC Part 90 TIS rules to allow signal intensity above the standard 2.0 mV/m limitation.)

See American Association of Information Radio Operators.
Absorbant Glass Mat (AGM)     

Sealed lead-acid battery designed to reduce weight and improve reliability. The sulfuric acid is absorbed by a very fine fiberglass mat, making the battery spill-proof, which enables shipment without hazardous material restrictions. When compared to conventional flooded-lead-acid batteries, AGM has these advantages: it is high-current capable, maintenance-free, with a long life, low temperature operation, light weight, longer storage time between charges, the ability to deep-cycle, vibration resistan5. AGM disadvantages include: it is sensitive to heat and to overcharging.

See Alternating Current.

See Authorized Equipment List.

See Absorbant Glass Mat.

See Amp Hour.
ALERT AM Emergency Advisory Radio System     
Fixed Emergency Advisory Radio station from Information Station Specialists used primarily for notifying motorists of emergencies and instructing them how to proceed. The system is outfitted with NOAA's Emergency Alert System 'all hazard' warning interruptions targeted to specific counties; multiple power and programming options, such as GPS synchronization for multi-station groupings, battery backup to continue operation during power outages and a large cabinet for flexibility. FCC-licensed. Range 25-75 square miles. Used in combination with Flashing ALERT Signs. See the ALERT AM webpage.
All-Hazard Warning System

See Emergency Alert System.
Alternating Current (AC)     

A flow of electric charge that periodically reverses direction, often distinguished from Direct Current (DC). The usual waveform of an AC power circuit is a sine wave, such as audio and radio signals carried on electrical wires. An important goal is often recovery of encoded (or modulated) information onto the AC signal.

See Amplitude Modulation.
American Association of Information Radio Operators (AAIRO)      

A nonprofit association, founded in 2008, of operators, licensees and interested others from public agencies nationwide who manage Travelers Information Stations (TIS and HAR) to broadcast to motorists public safety/service messages. See the group's mission and more at AAIRO's website.

Unit of electric current.
Amp Hour (Ah)     

Unit of electric charge equal to the charge transferred by a steady current of one ampere flowing for one hour, frequently used in measuring batteries. It is not a unit of energy. In a battery system, for example, accurate calculation of the energy delivered requires integration of the power delivered (product of instantaneous voltage and instantaneous current) over the discharge interval. Generally, the battery voltage varies during discharge; an average value or nominal value may be used to approximate the integration of power.
Amplitude Modulation (AM)     

A method of radio modulation that varies carrier wave amplitude. Used by Travelers Information Stations (TIS and HAR) and AM broadcast stations in the United States. It works by varying the strength (amplitude) of the carrier in proportion to the waveform being sent, which contrasts with Frequency Modulation (FM), where the frequency of the carrier signal is varied. AM frequency range is 530 to 1710 kHz.
AP55 Digital Message Player

See Digital Message Player.
Authorized Equipment List (AEL)     

A generic list of equipment allowable under the US Department of Homeland Security Federal Emergency Management Agency's (FEMA) major grant programs. Specific products may be linked to the Standardized Equipment List as examples, then indirectly linked to the AEL from there.
Broadcast Station

A conventional radio station authorized by the FCC under Part 73 Rules to broadcast music, news and other programming on AM or FM to the community to which it is licensed. Broadcast stations in the United Stations operate at powers of up to 50,000 watts on AM on frequencies 540-1700 and up to 330,000 watts on FM frequencies 88.1 to 107.9. See Travelers Information Station differences.
Call Sign

Federal Communications Commission Rules (Part 90) govern the licensing of Travelers Information Stations (TIS and HAR) issued to local government entities such as states, cities and counties. The Commission assigns 7-character call signs to all − 4 alpha letters, followed by 3 numbers.

Modern station call signs that are issued by the FCC begin with a “W” (though many years ago some were issued that started with a “K”). The next 3 letters and 3 numbers are sequential, based on when the Commission grants each license.

Although the Commission does not permit applicants to request specific call signs, in a few instances (when licensees indicated certain call signs were objectionable), the FCC granted changes.

The FCC requires that the full 7-character call sign be broadcast every 30 minutes (or more) in English. Sometimes station operators inadvertently drop off the three numbers of the call sign, probably because standard broadcast stations (licensed under FCC Part 73 Rules) don't have numbers in their call signs and have only three or four characters (WGN, WABC, etc.).

Travelers Information Stations operated by federal government agencies are licensed through the NTIA (National Telecommunication Information Agency) rather than the FCC and do not necessarily follow the same format. In some instances, these call signs might begin with a "K," have only three letters or no numbers.

Information Stations authorized by branches of the military are not issued call signs

See Common Alerting Protocol.

See Co-Channel Interference.
Co-Channel Interference (CCI)     

Crosstalk from 2 different radio transmitters using the same frequency. There can be several causes, for example, cellular mobile networks, adverse weather conditions, poor frequency planning, overly crowded radio spectrum, daytime versus nighttime, signal cancellation.
Common Alerting Protocol (CAP)    

An XML-based data format for exchanging public warnings and emergencies among alerting technologies. CAP allows a warning message to be consistently disseminated simultaneously over many warning systems to many applications. CAP increases warning effectiveness and simplifies the task of activating a warning for responsible officials. See also Emergency Alert System.
Continuous Tone Coded Squelch System (CTCSS)     

A circuit used to reduce the annoyance of listening to other users on a shared communication channel.

See Continuous Tone Coded Squelch System.

See Direct Current.
Digital Message Players     

Device used to record, store and repeat messages for Travelers Information Stations (TIS and HAR) by Information Station Specialists. See the following summaries of current models: IP76, and NX8R. See also a Comparison Chart for Audio Control Methods.
Direct Current (DC)     

The unidirectional flow of electric charge produced by sources such as batteries and solar cells. The electric current flows in a constant direction, distinguishing it from Alternating Current.

See Dual-Tone Multi-Frequency Signaling.
Dual-Tone Multi-Frequency Signaling (DTMF)     

Used for telecommunication signaling over analog telephone lines in the voice-frequency band between telephone handsets and other communication devices and the switching center. The version of DTMF developed by Western Electric that is used in push-button telephones for tone dialing is known as "Touch Tone," a registered trademark of Bell Telephone.

See Emergency Alert System.
Electromagnetic Interference (EMI)     

Also called Radio Frequency Interference (RFI) when associated with radio systems, EMI is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. The disturbance may interrupt, obstruct or otherwise degrade or limit the effective performance of the circuit. The source may be any object, artificial or natural that carries rapidly changing electrical currents, such as an electrical circuit, the sun or Northern Lights. EMI can intentionally be used for radio jamming or can occur as a result of spurious emissions through intermodulation products.
Emergency Advisory Radio Station     

Specially outfitted Travelers Information Station used primarily to broadcast emergency instructions to motorists before, during and after crises. The ALERT AM fixed system, RadioSTAT hand-portable station and VoiceStar trailer-mounted stations are three primary examples from Information Station Specialists.
Emergency Alert System (EAS)     

Jointly coordinated by the Federal Emergency Management Agency, the Federal Communications Commission (FCC), and the National Weather Service, EAS is a national warning system, begun in 1997. The EAS system was preceded by the Emergency Broadcast System begun after World War II to enable the US President to speak to the entire country in fewer than 10 minutes during national emergencies. The federal aspect of the EAS system has been tested but has never activated. The National Weather Service’s part of the system is designed to alert the public during local weather emergencies, such as tornadoes and flash floods. It is in operation on a daily basis throughout the United States.

EAS regulations and standards are governed by the Public Safety and Homeland Security Bureau of the FCC. Each state and several territories have their own EAS plan; and EAS has become part of IPAWS – the Integrated Public Alert and Warning System, a program of FEMA. Digital EAS codes make it possible to target warnings for automatic broadcast to citizens through NOAA weather radio receivers programmed through Specific Area Message Encoding (SAME) that comes standard on Information Station Specialists' ALERT AM and ITS6000 systems and as an option on the portable VoiceStar radio system.
Emergency Notification Systems (ENS)     

Emergency Notification Systems acronym.
Emergency Override Message

A recorded message, message format or live feed designed to take precedence in an emergency and lock out secondary messages from broadcasting. Example: when the National Weather Service issues a tornado warning, day-to-day messages on the radio station are interrupted and locked out while being superseded by the NWS warning during the time that it is pertinent. See also Emergency Advisory Radio Station.

See Electromagnetic Interference.
ENcast Emergency Notification Broadcast System

Information Station Specialists option, introduced in 2014, to broadcast text-based emergency notifications over a Travelers Information Station automatically. See the ENcast webpage.

See Emergency Notification Systems.
EventCAST Radio Stations and LED Signs     

Portable radio station and sign purchase/rental service from Information Station Specialists, introduced in 2017 as a replacement service formerly called RadioExpress. Designed for event broadcasting, signal testing and other temporary applications, EventCAST offers complete, portable AM band Travelers Information Stations with a 3-5 mile radius range from the antenna center point (25-75 square miles). Each station's weatherproof design with quick-erect antenna system allow setup in almost any environment. Portable LED changeable message signs with various mounting styles are part of the service. See the EventCAST webpage.
Exterior Dimensions      

Length, width and height measured on the outside surfaces of a container, such as a box, enclosure, trailer, etc., used to determine the dimensions and volume of same. See also Interior Dimensions.
FAS6000 Flashing Beacons and Controller    

Allows an operator to turn on or off a pair of highway sign of flashing amber beacons, through wireless means, without the need to compromise the AM broadcast signal the sign might announce. The FAS6000 controller includes a solar-powered collection-and-storage system, receiver, two amber 8" or 12" LED flashing beacons, weatherproof enclosure, mounts, wiring and instructions. Wireless control methods vary. Typically used on roads of 55 miles per hour and higher. See the FAS6000 webpage.
FASTrack Quick-Erect Portable Sign    
FHWA/NFPA-approved for use at emergency scenes, one-piece FASTrack signs are portable and quick to assemble during emergencies. They are available with custom sign text and optional text overlays. See the FASTrack webpage.

See Federal Communications Commission.

See Part 90 TIS Rules.
Filter, HQ5.0 Audio

See HQ5.0 Audio Filter.
Federal Communications Commission (FCC)     

An independent US federal agency, created by Congressional statute to regulate interstate and international communications by radio, television, wire, satellite, and cable in all 50 states, the District of Columbia and US territories. The FCC works toward goals in the areas of broadband, competition, the spectrum, the media, public safety and homeland security. See also FCC rules for Travelers' Information Stations.
Flashing ALERT Sign      

Wireless-controlled, solar-powered beacon signs from Information Station Specialists that may be triggered remotely to advise motorists to tune to a special radio signal for information or to take a specific action in any public safety situation. See the Flashing ALERT Sign webpage.
Flashing Beacons and Controller

See FAS6000 Flashing Beacons and Controller and Flashing ALERT Sign.

See Frequency Modulation.
Forward Power (FP)

A standing wave on a transmission line can be composed of 2 traveling waves, 1 moving toward the load (the forward wave) and 1 moving in the opposite direction (reflected wave).
Frequency Modulation (FM)     

A method of radio modulation in which the frequency of the carrier wave are varied. FM frequency range is 88 to 108 MHz. See also amplitude modulation.

See Ground Fault Circuit Interrupter.

See Ground Fault Interrupt.
Global Positioning System (GPS)     

A space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.

See Global Positioning System.
GPS Frequency Stabilization     

A method of synchronizing the carrier and/or the audio of multiple (typically overlapping) Information Radio signals in order to reduce interstation interference effects.
Ground Fault Circuit Interrupter (GFCI)     

Device to quickly disconnect current to prevent serious harm from an ongoing electric shock. Known variously as "Ground Fault Interrupter," "residual-current device," "residual-current circuit breaker," "appliance leakage current interrupter."
Ground Fault Interrupter (GFI)     

GFIs compare currents leaving hot conductors to currents returning on neutral conductors, disconnecting circuits if that difference exceeds 4-6 milliamps. Required in the US and Canada for potentially wet locations, GFIs are cheaper than Ground Fault Circuit Interrupt (GFCI) circuit breakers and can be wired to feed additional downstream outlets so that putting one GFCI receptacle in a circuit protects all downstream plugs, lights and switches. GFIs are recommended for power tool outlets.

Device used to provide horizontally oriented grounding of Travelers Information Station antenna systems. The more robust the grounding, the more efficient the antenna system and the stronger the resulting signal ot a given transmitter wattage. The PowerPlane "flex" groundplane is one example. See why groundplanes are important, how they're made and installed on this TechTalk webpage.

For installations where vertical grounding is required but the antenna must be mounted on an existing pole or structure, an Information Station Specialists Unirod may be employed. The Unirod is from 10 to 40 feet in length (longer Unirods for long wavelength frequencies) and is augured into the earth beneath the antenna pole, installed with a highly conductive soil backfill. Unirods are also recommended when the most efficient possible grounding method is required. See also Groundplane and Vertical Profile Antenna System and a TechTalk article, entitled Why Antenna Grounding is Important, How It Works & Is Installed.

See Highway Advisory Radio.
HearMoreInfo Spotcast and Streamcast     

A simple, affordable Information Station Specialists service to deliver timely, targeted high quality audio directly to smartphones, tablets, laptops and PCs. SpotCASTs audio productions in file form always begin at the beginning, which is important for programs where the order of presentation is critical. StreamCASTs allow Internet linking of audiences to a continuous program, such as the broadcast program of a Travelers Information Station or the play-by-play of a live event. Both styles may be full production, including music, and may be sponsored, making the service revenue-neutral – or even profitable for operators.
Hertz (Hz)

Unit of frequency in the International System of Units (SI) defined as 1 cycle per second, named for Heinrich Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves. See also Megahertz.

Interstation interference caused when unsynchronized co-channel (same frequency) radio station signals overlap and interact.
Highway Advisory Radio (HAR)     

Term Departments of Transportations (DOT) commonly use for Travelers Information Stations in place along highways for traffic-control. The ITS6000 fixed and VoiceStar portable stations are prime examples of Highway Advisory Radio Systems.
HQ5.0 Audio Filter     

Passive design requiring no power, commonly added to portable radio stations such as RadioSTAT and VoiceStar and those with cabinets in which equipment is mounted to a back panel, such as legacy Information Stations. Can be added to any Information Station Specialists' radio station, however. Requires that the transmitter's internal 3000 Hz filter be disabled in conjunction with the addition of the filter. Exclusively permitted by the FCC for operation as part of Information Station Specialists' TR6000 Transmitter System.
HQ5.1 Audio Processor     

Active device requiring power that increases broadcast quality, i.e., adds compression and limiting, thereby boosting loudness and functional range of broadcasts. Commonly used with ALERT AM, ITS6000 and new Information Stations. Requires that the transmitter's internal 3000 Hz filter be disabled in conjunction with the addition of the processor. Exclusively permitted by the FCC for operation as part of Information Station Specialists' TR6000 Transmitter System.

See InterAgency Board.
IAB Interactive Standardized Equipment List

See Standardized Equipment List.
i A.M. Radio / Talking House

Limited-range (300 feet) radio station acquired by Information Station Specialists in 2017 to serve the microbroadcasting market, for example, realtors, churches, business, hobbyists, schools and visitor bureaus.
InfoMAX License-Free Radio Station

Early trade name for InfOspot License-Free Radio Station.
InfoRadio Format

Professional broadcast recording service from Information Station Specialists. See Professional Recording Services webpage.
Information Radio Station      

General term for Travelers' Information Station or Highway Advisory Radio Station.
Information Station Classic or IP      

Fixed Travelers Information Station used primarily for broadcasting general information to motorists. May be used in emergencies. Versions include “IP” – operable via network/USB – and “Classic” – operable voicemail-style via telephone or locally. FCC-licensed. Typical coverage:  25-75 square miles. Used in combination with Flashing ALERT Signs. See the Information Station webpage.
Information Station Specialists (ISS)     

The USA's best known source for Travelers Information Stations (TIS and HAR),  advisory signs and the specialized services required to transmit spoken messages to motorists − the only such source providing products entirely made in America. See What's Special about the Specialists webpage.
InfOspot License-Free Radio Station     

Formerly InfoMAX.

License-free low power Information Radio Station for short-range, visitor, general and commercial applications. No license is required per FCC rules Part 15.221. See InfOspot webpage.
Integrated Public Alert Warning System (IPAWS)     

An architecture that unifies the United States' Emergency Alert System, National Warning System, Wireless Emergency Alerts, and NOAA Weather Radio, under a single platform.
Intelligent Transportation System (ITS)     

Technology along US highways that allows motorists to be better informed to make safer and smarter use of transport networks. ITS6000 fixed and VoiceStar portable radio stations offered by Information Station Specialists operate as part of Intelligent Transportation networks as do FAS6000 flashing sign controllers and beacons.
InterAgency Board (IAB)     

Under the auspices of the US Attorney General, in 1998, the InterAgency Board for Equipment Standardization and Interoperability was founded. Its work is influenced by officials from the Departments of Defense and Justice, with participation from local, state and federal government emergency management agencies. The group's mission is to strengthen the nation's ability to prepare for and respond to emergencies by developing a common language, for example, the Standardized Equipment List, and common methods of practice. Visit the IAB's website.
Interior Dimensions     

Length, width and height measured inside a container, such as a box, enclosure, trailer. etc., used to determine interior volume and how smaller items can best be arranged within. See also Exterior Dimensions.
IP8 Digital Message Player

See Digital Message Player.
IP76 Digital Message Player

See Digital Message Player.

See Integrated Public Alert Warning System.

See Information Station Specialists.

See Intelligent Transportation System.
ITS6000 Highway Advisory Radio Network    

Highway Advisory Radio Stations and related flashing beacon accessories from Information Station Specialists that are used by Departments of Transportation as part of ITS projects. See the ITS6000 webpage.
Kilo Ampere (kAmp)     

A measurement equal to 1000 amperes (100 amps) of current in an electrical circuit.
Kilohertz (kHz)     

The term “hertz” is equivalent to “cycles per second.” A kilohertz is 1000 cycles per second. The frequency of a Travelers Information Station is measured in kilohertz, with 530 kHz being the lowest frequency and 1710 kHz the highest.
Kilometer (km)     

Metric unit of length equivalent to 1000 meters or 0.62137 miles.

See Kilo Ampere.

See Kilohertz.

See Kilometer.

See Light Emitting Diode.
Light Emitting Diode (LED)     

Semiconductor device that emits visible light when an electric current passes through it. The light is not particularly bright, but in most LEDs, it is monochromatic, occurring at a single wavelength.
LIGHTNING LED Message Sign  

Affordable and easy to set up, this portable changeable message sign programs via a wireless remote control and can display messages indoors or out. Operates up to 30 hours on a single battery charge, indefinitely on land power. Displays new messages instantly. Stores hundreds for future use. Comes with carrying case and mounting options. See LIGHTNING LED Message Sign webpage.

See Responders Knowledge Base.
Low Power AM (LPAM)     

Descriptor often used for a Travelers Information Station.
Low Power FM (LPFM)     

Non-commercial educational broadcast service, established by the FCC in 2000. Public safety agencies, may use Low Power FM Stations with special provisions and restrictions. Licenses may be requested during specific “filing windows” announced periodically by the FCC. LPFM stations have special licensing and programming requirements that make them less efficient for public safety and transportation agency applications. See the FCC's LPFM webpage.

See See Low Power AM.

See Low Power FM.

See Milliamp.
Megahertz (MHz)    

One million hertz, used to measure the frequency of radio

Broadcast recordings or live voice transmissions.

See Megahertz.
Milliamp (Ma)     

Unit of current equal to 1/1000 (10-3) of an Amp used to express flow rate of electric charge.
Millivolts per Meter (mV/m)     

Unit of electromotive force equal to 1/1000 of a volt (the standard unit of potential difference and electromotive force). See also Volts of Alternating Current and Volts of Direct Current.

In electronics and telecommunications, the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted. The information may take the form of audio or data.

See Message.

See Millivolts per Meter.
National Electrical Manufacturers Association (NEMA)       

Group of approximately 450 electrical equipment and medical imaging manufacturers in the US, founded in 1926, headquartered in Virginia. See website.
National Emergency Management Association (NEMA)     

Nonprofit, nonpartisan association of emergency management and homeland security professionals,  established in 1974, when state directors of emergency services first united to exchange information on common emergency management issues that threatened their constituencies. See website.
National Oceanic and Atmospheric Administration (NOAA)     

Scientific agency within the US Department of Commerce focused on conditions of the oceans and the atmosphere. NOAA warns of dangerous weather (National Weather Service), charts seas and skies, guides use and protection of ocean and coastal resources and conducts research to improve understanding and stewardship of the environment. Go to NOAA's website.
National Telecommunication Information Agency (NTIA)     

Executive Branch agency that advises the US President on telecommunication and information policy issues. NTIA tries to expand broadband Internet access and adoption in America and use of spectrum by all to ensure the Internet remains an engine for continued innovation and economic growth. NTIA licenses federally operated Travelers Information Stations (TIS and HAR). Visit the NTIA website for details.
National Weather Service (NWS)      

Part of the federal government's National Oceanic and Atmospheric Administration (NOAA), tasked with providing forecasts, public warnings, and other products to organizations and the public for the purposes of protection, safety, and general information. This is done through a collection of national and regional centers and 122 local weather forecast offices. Go to the NWS website.

See National Electrical Manufacturers Association or National Emergency Management Association.

See National Oceanic and Atmospheric Administration.
NOAA All Hazard Alerts

See Emergency Alert System.

See National Telecommunication Information Agency.

See National Weather Service.
NX8R Digital Message Player

See Digital Message Player.
Part 90 FCC Rules     

Rules originating in 1977 and updated in 2013 that govern the licensing and operation of Travelers Information Stations (TIS and HAR) in the United States. See a PDF of the Rules as updated in 2013 and the 2014 FCC TIS Compliance Guide.

See Potential Interference Notification Service.

See Private Line.

List of programmable broadcast recordings for a Travelers Information Station that normally play on the air in a repeating cycle. See also Digital Message Player.
Potential Interference Notification Service (PINS)     

Service began in 2015 by Information Station Specialists to protect new or existing Travelers Information Stations for life. Each month the company scans the radio spectrum and advises licensees immediately if there are interference issues, including any changes in full-power broadcast stations that could negatively impact an information station’s operation.
Power Loss Notification Module

Travelers Information Station option that automatically dials up to 4 telephone numbers, including cell phones and pagers should loss of power be sensed.
PowerPlane Factory-Assembled Groundplane     

Previously patented Information Station Specialists groundplane composed of 62 copper wire ground radials (12-gauge) bonded to an inner ring of (4-gauge) copper wire. Each radial forms a loop that extends outward from the inner ring 10 feet in every direction, creating a fan pattern. Installed at fixed antenna locations. A flexible version ("Flexplane") may be used with portable/temporary Travelers Information Stations' antenna systems. See a TechTalk article, entitled Why Antenna Grounding Is Important.
PowerSTAT Portable Energy Source

Introduced in 2011. Discontinued in 2017. A pure sine-wave AC inverter plus high capacity charger with hefty battery pack, all packaged in a weather-resistant portable case. Charged at any standard 120-volt AC power outlet. Provided pure, clean, energy, quietly. Approved for indoor use. Could stand alone or be employed as a power source for the RadioSTAT Portable Emergency Advisory Radio Station.
Private Line (PL)     

In wired telephony, a tie-line service that involves dedicated circuits, private switching and/or predefined transmission paths, virtual or physical, that provide communication among specific locations. Most connect only two locations though they may be switched at either end or both. Some have multiple drop points.
Processor, HQ5.1 Audio

See HQ5.0 Audio Processor.
Radio Frequency (RF)    

A rate of oscillation that corresponds to the frequency of radio waves and the alternating currents that carry radio signals. See Wikipedia details.
Radio Frequency Interference (RFI)    

Disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source, degrading performance.
RadioExpress Portable Information Radio Service

Tradename revised to EventCAST in 2017. See the EventCAST webpage.
RadioSTAT Portable Emergency Advisory Radio Station     

Compact, hand-portable Emergency Advisory Radio Station from Information Station Specialists that can be easily taken to an incident by land, sea or air. Housed in an easy-to-transport, high-impact, weather-resistant case, the station can operate from a fixed location when not required in the field. Controlled via flash drive or network. FCC-licensed. Range 25-75 square miles. Used in combination with FASTrack Signs.

See Reflected Power.
Reflected Power (REF)     

A standing wave on a transmission line can be composed of 2 traveling waves, 1 moving toward the load (the forward wave) and 1 moving in the opposite direction (reflected wave).
Responders Knowledge Base (RKB)     

Also referred to as Lessons Learned Information Sharing ( Knowledge Base

An Internet resource intended to "unify key information sources that support decision-making across the emergency management and homeland security communities." Visit our Funding Resources for Emergency TIS Applications webpage for details about how the RKB relates to AEL, SEL and IAB.

See Radio Frequency.

See Radio Frequency Interference.

See Responders Knowledge Base.
RoadRunnR Portable Highway Advisory Radio System

Trailer-mounted portable Highway Advisory Radio System introduced by Information Station Specialists in 2000. See also VoiceStar.

See Specific Area Message Encoding.

See Standardized Equipment List.
Sequential, Two Tone

See Two-Tone Sequential.
Short Message Service     

Short Messaging Service known as texting. For example, all Information Station Specialists fixed signage products may be triggered directly by any emergency notification system capable of sending messages in SMS text format. See Flashing ALERT Sign, FAS6000 Flashing Beacons and Controller, and/or Stealth Sign.
Signal Booster

See 2X Signal Booster.
Signal Measurement Radio Receiver (SMR)      

A portable radio receiver used for monitoring and measurement of AM radio signals. Displays AM signal levels so they may be documented. Used to comply with FCC Rules. See details on the SMR webpage.

See these fixed signs each: Flashing ALERT Sign, FAS6000 Flashing Beacons and Controller, Stealth Sign fixed signs. See also these portable signs each: FASTrack Quick-Erect Sign, LIGHTNING LED Message Sign and VoiceStar.

In mathematics, the sine is a trigonometric function of an angle. A sine wave or sinusoid is a mathematical curve that describes the smooth repetitive oscillation of a radio wave.
Single Pole Double Throw (SPDT)     

A switch that may be thrown in 2 directions, allowing current to pass to 2 different terminals, depending upon which way the throw is made. See also Single Pole Single Throw
Single Pole Single Throw (SPST)     

A switch that makes contact between 2 discrete terminals, allowing electrical current to flow between them when the switch (throw) is closed and not when it is open. See also Single Pole Double Throw.

A phenomenon on AM band channels caused by nighttime cooling in the ionosphere, prompting AM radio waves to reflect back to Earth at distant locations. See "What is skywave? The difference is Night and Day," TechTalk, 2013.

See Signal Measurement Radio Receiver.

See Short Message Service.
Special Temporary Authority (STA)     

The authority granted to an applicant to operate a radio station or service for a limited time for a specified reason, such as an emergency, for testing or for restoration of communications or other short-term operations, whereby the applicant has shown that, due to extraordinary circumstances, s/he cannot wait for the normal licensing process to conclude.
Specific Area Message Encoding (SAME)      

Digital codes keyed to each county, programmed into a NOAA weather radio receiver so EAS 'all hazard' alerts will broadcast over specialized weather receivers and Travelers Information Stations. See the SAME Programmable Weather Receiver webpage.
SpotCAST Internet Broadcast Service

See HearMoreInfo.

See Single Pole Double Throw.

See Single Pole Single Throw.

See Special Temporary Authority.
Standardized Equipment List (SEL)     

Also known as InterAgency Board (IAB) Interactive Standardized Equipment List

Guideline used voluntarily, intended to promote interoperability and standardization across the emergency response community at local, state and federal levels by offering standard references and common terminology. See the SEL webpage. For additional details, visit the Funding Resources for Emergency TIS Applications webpage.
Standing Wave Ratio (SWR)     

Standing-wave ratio (SWR) is a mathematical expression of the non-uniformity of an electromagnetic field  on a transmission line, such as coaxial cable and/or a connected antenna system. Antennas are adjusted to make the SWR as low as possible (1:1) in order to make the antenna efficiency as high as possible. Typically, a SWR as high as 2:1 is suitable for Travelers Information Station operations. A 2:1 SWR correlates to a 10:1 ratio of forward to reflected transmitter power.
Stealth Sign    

Fixed-message LED signs that are dark when not activated. See Stealth Sign webpage.
StreamCAST Internet Broadcast Service

See HearMoreInfo.
Streaming Broadcasts to the Internet

See HearMoreInfo.

See Standing Wave Ratio.
SX200 Wattmeter

Information Station Specialists' wattmeter.
Talking House  / i A.M. Radio

Limited-range (300 feet) radio station acquired by Information Station Specialists in 2017 to serve the microbroadcasting market, for example, realtors, churches, business, hobbyists, schools and visitor bureaus.
Tip and Ring (T/R)

Names of the 2 conductors or the side of a telephone line.

See Travelers' Information Station.
TIS Rules

See Part 90 FCC Rules.

See Dual-Tone Multi-Frequency Signaling (DTMF).
TR6000 HQ5.0 Transmitter      

A 10-watt AM transmitter employed by Information Station Specialists for all licensed Travelers Information Stations the company provides. The TR6000 HQ5.0 is type accepted according FCC standards for the TIS service. See details on this TR6000 HQ5.0 webpage. See also HQ5.0 Audio Filter and HQ5.1 Audio Processor.
Travelers Information Station (TIS)    

Also referred to generally as Information Radio Stations, and in specific applications and station setups, as Emergency Advisory Radio or Highway Advisory Radio.

Legal term used by the Federal Communications Commission to define a 10-watt radio station that operates on AM-band frequencies 530-1700 kHz; signal coverage is 2.0 mV/m at 1.5 km, which typically yields a signal radius of 3-5 miles. The Federal Communications Commission licenses the stations to state and local government agencies, such as regional emergency managers, under Part 90.242 Rules, issued in 1977 and updated and clarified in the 2014 FCC TIS Compliance Guide. Federal agencies, such as National Parks and the Department of Homeland Security, obtain authorization for their TIS stations to operate separately through the National Telecommunication and Information Administration. TIS broadcasts are intended for motorists and must be commercial-free, voice-only public-safety/service-oriented. Emergency managers may broadcast any information to preserve life and property when danger is imminent. Motorists are notified to tune to the stations via road signs, which typically incorporate flashing beacons.

ISS trade names include ALERT AM, RadioSTAT, VoiceStar, ITS6000 and the Information Station (click each preceding trade name for individual descriptions).
Two-Tone Sequential     

Also known as 1+1

"Two-tone sequential" is a dual-tone selective calling method used in one-way paging transmissions.

See Ultra High Frequency.
Ultra High Frequency (UHF)     

The designation for radio frequencies in the range of 300 MHz and 3Ghz. UHF radio waves propagate mainly by line of sight.

See Groundrod.

See Volts of Alternating Current.

See Volts of Direct Current.
Vertical Profile Antenna System

See VP9000 Vertical Profile Antenna System.
Very High Frequency (VHF)    

The International Telecommunication Union (ITU)-designated range of radio frequency electromagnetic waves from 30 MHz to 300 MHz, with corresponding wavelengths of 1 to 10n meters. (ITU coordinates the shared global use of the radio spectrum.) Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF).

See Very High Frequency.
VoiceStar Portable Advisory Radio Station and/or Changeable Message Sign     

Solar-powered, wireless controlled, trailer-mounted, portable Travelers Information Station (TIS and HAR) with optional changeable message sign. Throws a full 25-to-75 square-mile signal (3 to 5 mile radius) to motorists. Often used in association with highway construction for incidents and emergencies. See VoiceStar webpage. Information Station Specialists offers VoiceStar in partnership with the American Signal Corporation.
Volts of Alternating Current (VAC)     

The measured electrical potential (voltage) of an Alternating Current circuit.
Volts of Direct Current (VDC)     

The measured electrical potential (voltage) of a Direct Current.
Volume Units (VU)     

Base units of length and volume linked in the metric system. By definition, a liter is equal to the volume of a cube exactly 10 cm tall, 10 cm long, and 10 cm wide. Because the volume of this cube is 1000 cubic centimeters and a liter contains 1000 milliliters, 1 milliliter is equivalent to 1 cubic centimeter.
VP9000 Vertical Profile Antenna System      

A previously patented aluminum antenna support pole and antenna grounding system, in one. The antenna lightning arrestor and cables are housed inside the pole, accessible through a service hatch to discourage vandalism. VP9000 requires less ground disturbance and installation space and is an unobtrusive antenna-grounding solution for Travelers Information Stations (TIS and HAR). See also a TechTalk article entitled, Why Antenna Grounding Is Important, How It Works and Is Installed.

See Volume Units.

See Workstation Audio Control.

See Wireless Audio Link System.

A valuable tool for installing and maintaining Travelers Information Stations. The wattmeter is used to tune the station's antenna and to determine if the antenna and transmitter are working efficienty (by allowing the measurement of the antenna system's forward and reflected power). Trade name:  SX200. See TechTalk article:  Troubleshooting with a Wattmeter.
Wireless Audio Link System (WAL)     

A method of linking a continuous audio program from a central source to multiple Travelers Information Stations by RF means.
Workstation Audio Control (WAC)    

An audio source for Travelers Information Stations that allows on-screen PC control of broadcast messages, utilizing a dedicated workstation and/or across a network. WAC enables high quality, natural audio recordings, text-to-speech generation, broadcast audio processing, visual audio editing, scheduled playlist changes and event logging. See the Workstation Audio Control webpage. See also a webpage comparing Information Station Specialists Audio Control Methods.

Founding & Firsts Audio Control Methods Alert Stations across America FCC Frequencies & Licenses Site Map
Common Applications Case Studies Installation, Testing, Training
Emergency Advisory Radio FAQs Professional Recordings
Features Compared FCC-Permitted Broadcasts Rentals
Highway Advisory Radio Glossary of Radio Termis Streaming
      License-Free Stations News from The Source    
Travelers' Information Stations Operators' Zone
Why Customers Say They Buy

©  1983-2019  • Information Station Specialists, Inc. •  All Rights Reserved
PO Box 51, Zeeland, Michigan, USA, 49464-0051, Phone 616.772.2300, Fax 616.772.2966, Email: info at theRADIOsource dot com

The USA's best known source for Emergency Advisory Radio Stations, Travelers' Information Stations, Highway Advisory Radio & related products/services.

 Trademarks: 2X Signal Booster, ALERT AM Emergency Advisory Radio System, AP55 Digital Message Player, ENcast Emergency Notification Broadcast System, FAS6000 Flashing Beacons & Controller, FASTrack Quick-Erect Sign, Flashing ALERT Sign System, Free-Radiate On-Premise Radio Broadcast System, HearMoreInfo Internet Broadcasts, , Information Station Specialists, InfoRadio Format, Information Station Classic, Information Station IP, InfOSpot License-Free Radio Station, IP8 Digital Message Player, IP76 Digital Message Player, ITS6000 Highway Advisory Radio Network, LIGHTNING LED Portable Changeable Message Sign, NX8R Digital Message Player, Potential Interference Notification Services (PINS), PowerPlane Flex  Factory-Assembled Groundplane, EventCAST Portable Information Radio Service, RadioSAFE Wide-Area Emergency Broadcast System, RadioSTAT Portable Emergency Advisory Radio Station, Signal Measurement Radio Receiver, SpotCAST Internet Broadcast Service, Stealth Sign, StreamCAST Internet Broadcast Service, Stylized ISS Logo, SX200 Watt Meter, Talking House , TR6000 HQ5.0 Transmitter, TR6000 15.73 Transmitter, VP9000 Vertical Profile Antenna System, VoiceStar Portable Highway Advisory Radio Station (with our without Changeable Message Sign), Wireless Audio Link.

Information Radio Stations is a generic term synonymous with Travelers Information Stations (TIS), Highway Advisory Radio Stations (HAR) / Highway Information Systems & Low Power Radio Stations (LPR). Operation of the stations is governed by FCC Part 90.242 Rules. A FCC license is required. Information Radio Stations may be fixed or portable. Subcomponents may include transmitter, antenna and ground system, digital voice player, wateter, cabinet with conventional or Corbin locks, lightning arrestors for RF, power and telephone lines, coaxial cable. Most stations employ black maximized antennas to discourage ice accumulation and security measures to prevent unauthorized program access. Options include synchronization, battery backup, solar power, remote programming by local, network or telco, multi-station audio distribution via RF or LAN / WAN or wireless network.