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115-1105: An amateur radio repeater is an electronic device that receives a weak or low-level amateur radio signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. Many repeaters are located on hilltops or on tall buildings as the higher location increases their coverage area, sometimes referred to as the radio horizon , or "footprint". Amateur radio repeaters are similar in concept to those used by public safety entities (police, fire department, etc.), businesses, government, military, and more. Amateur radio repeaters may even use commercially packaged repeater systems that have been adjusted to operate within amateur radio frequency bands, but more often amateur repeaters are assembled from receivers, transmitters, controllers, power supplies, antennas, and other components, from various sources. In amateur radio , repeaters are typically maintained by individual hobbyists or local groups of amateur radio operators . Many repeaters are provided openly to other amateur radio operators and typically not used as

230-440: A POTS / PSTN telephone line to allow users to make telephone calls from their keypad-equipped radios. These advanced services may be limited to members of the group or club that maintains the repeater. Many amateur radio repeaters typically have a tone access control ( CTCSS , also called CG or PL tone ) implemented to prevent them from being keyed-up (operated) accidentally by interference from other radio signals. A few use

345-466: A call sign on the air to legally identify the operator or station. In some countries, the call sign assigned to the station must always be used, whereas in other countries, the call sign of either the operator or the station may be used. In certain jurisdictions, an operator may also select a "vanity" call sign although these must also conform to the issuing government's allocation and structure used for Amateur Radio call signs. Some jurisdictions require

460-659: A remote base station by a single user or group. In some areas multiple repeaters are linked together to form a wide-coverage network, such as the linked system provided by the Independent Repeater Association which covers most of western Michigan, or the Western Intertie Network System ("WINsystem") that now covers a great deal of California, and is in 17 other states, including Hawaii, along with parts of four other countries, Australia, Canada, Great Britain and Japan. Repeaters are found mainly in

575-561: A DC voltage whenever the desired tone is present. The DC voltage is used to turn on, enable, or unmute the receiver's speaker audio stages. When the tone is present, the receiver is unmuted, when it is not present the receiver is silent. Because period is the inverse of frequency, lower tone frequencies can take longer to decode (depends on the decoder design). Receivers in a system using 67.0 Hz can take noticeably longer to decode than ones using 203.5 Hz, and they can take longer than one decoding 250.3 Hz. In some repeater systems,

690-452: A US citizen may operate under reciprocal agreements in Canada, but not a non-US citizen holding a US license. Many people start their involvement in amateur radio on social media or by finding a local club. Clubs often provide information about licensing, local operating practices, and technical advice. Newcomers also often study independently by purchasing books or other materials, sometimes with

805-468: A band's article for specifics. [ w ] HF allocation created at the 1979 World Administrative Radio Conference . These are commonly called the " WARC bands ". [ x ] This is not mentioned in the ITU 's Table of Frequency Allocations , but many individual administrations have commonly adopted this allocation under "Article 4.4" . [ y ] This includes a currently active footnote allocation mentioned in

920-405: A beep or chirp tone to signal that the timeout timer has reset. Conventional repeaters, also known as in-band or same-band repeaters, retransmit signals within the same frequency band , and they only repeat signals using a particular modulation scheme, predominately FM . Standard repeaters require either the use of two antennas (one each for transmitter and receiver) or a duplexer to isolate

1035-513: A carrier or noise squelch does not suppress any sufficiently strong signal; in CTCSS mode it unmutes only when the signal also carries the correct sub-audible audio tone. The tones are not actually below the range of human hearing, but are poorly reproduced by most communications-grade speakers and in any event are usually filtered out before being sent to the speaker or headphone. Radio transmitters using CTCSS always transmit their own tone code whenever

1150-471: A channel that has existing tone squelch users precludes the use of the 131.8 and 136.5 Hz tones as the digital bit rate is 134.4 bits per second and the decoders set to those two tones will sense an intermittent signal (referred to in the two-way radio field as "falsing" the decoder). CTCSS tones are standardized by the EIA/TIA . The full list of the tones can be found in their original standard RS-220A, and

1265-441: A club or organization for a period of time before a higher class of license can be acquired. A reciprocal licensing agreement between two countries allows bearers of an amateur radio license in one country under certain conditions to legally operate an amateur radio station in the other country without having to obtain an amateur radio license from the country being visited, or the bearer of a valid license in one country can receive

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1380-464: A club or organization generally requires that an individual with a current and valid amateur radio license who is in good standing with the telecommunications authority assumes responsibility for any operations conducted under the club license or club call sign. A few countries may issue special licenses to novices or beginners that do not assign the individual a call sign but instead require the newly licensed individual to operate from stations licensed to

1495-548: A codec in the user radio and along with the encoded audio, also send and receive user number and destination information so one can talk to another specific user or a Talk Group. Two such worldwide networks are DMR-MARC and Brandmeister. For example, a simplex gateway may be used to link a simplex repeater into a repeater network via the Internet. [ v ] All allocations are subject to variation by country. For simplicity, only common allocations found internationally are listed. See

1610-852: A country. For example, the peak envelope power limits for the highest available license classes in a few selected countries are: 2.25  kW in Canada; 1.5 kW in the United States; 1.0 kW in Belgium, Luxembourg , Switzerland, South Africa and New Zealand; 750 W in Germany; 500 W in Italy; 400 W in Australia, India, and the United Kingdom; and 150 W in Oman . CTCSS In telecommunications , Continuous Tone-Coded Squelch System or CTCSS

1725-613: A different CTCSS tone or no CTCSS. CTCSS tone codes are sometimes referred to as sub-channels , but this is a misnomer because no additional radio channels are created. All users with different CTCSS tones on the same channel are still transmitting on the identical radio frequency , and their transmissions interfere with each other; however; the interference is masked under most conditions. Although it provides some protection against interference, CTCSS does not offer any security against interception or jamming, and receivers without CTCSS enabled will still hear all traffic. A receiver with just

1840-553: A digital code system called DCS , DCG or DPL (a Motorola trademark). In the UK most repeaters also respond to a short burst of 1750 Hz tone to open the repeater. In many communities, a repeater has become a major on-the-air gathering spot for the local amateur radio community, especially during "drive time" (the morning or afternoon commuting time). In the evenings local public service nets may be heard on these systems and many repeaters are used by weather spotters . In an emergency or

1955-475: A disaster a repeater can sometimes help to provide needed communications between areas that could not otherwise communicate. Until cellular telephones became popular, it was common for community repeaters to have "drive time" monitoring stations so that mobile amateurs could call in traffic accidents via the repeater to the monitoring station who could relay it to the local police agencies via telephone. Systems with autopatches frequently had (and still have) most of

2070-563: A fee to obtain such a vanity call sign; in others, such as the UK, a fee is not required and the vanity call sign may be selected when the license is applied for. The FCC in the U.S. discontinued its fee for vanity call sign applications in September 2015, but replaced it as $ 35 in 2022. Call sign structure as prescribed by the ITU consists of three parts which break down as follows, using the call sign ZS1NAT as an example: Many countries do not follow

2185-558: A given period of time. In addition to contests, a number of amateur radio operating award schemes exist, sometimes suffixed with "on the Air", such as Summits on the Air , Islands on the Air, Worked All States and Jamboree on the Air . Amateur radio operators may also act as citizen scientists for propagation research and atmospheric science . Radio transmission permits are closely controlled by nations' governments because radio waves propagate beyond national boundaries, and therefore radio

2300-453: A national licensing process and may instead require prospective amateur radio operators to take the licensing examinations of a foreign country. In countries with the largest numbers of amateur radio licensees, such as Japan, the United States, Thailand, Canada, and most of the countries in Europe, there are frequent license examinations opportunities in major cities. Granting a separate license to

2415-432: A nuisance. The use of "ham" meaning "amateurish or unskilled" survives today sparsely in other disciplines (e.g. "ham actor"). The amateur radio community subsequently began to reclaim the word as a label of pride, and by the mid-20th century it had lost its pejorative meaning. Although not an acronym or initialism, it is often written as "HAM" in capital letters. The many facets of amateur radio attract practitioners with

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2530-463: A number after to indicate the political region; prefix CY indicates geographic islands. Prefix VA1 or VE1 is Nova Scotia , VA2 / VE2 is Quebec , VA3 / VE3 is Ontario , VA4 / VE4 is Manitoba , VA5 / VE5 is Saskatchewan , VA6 / VE6 is Alberta , VA7 / VE7 is British Columbia , VE8 is the Northwest Territories , VE9 is New Brunswick , VY0

2645-409: A pool of at least 350. To pass, 26 of the 35 questions must be answered correctly. The Extra Class exam has 50 multiple choice questions (drawn randomly from a pool of at least 500), 37 of which must be answered correctly. The tests cover regulations, customs, and technical knowledge, such as FCC provisions, operating practices, advanced electronics theory, radio equipment design, and safety. Morse Code

2760-432: A repeater was on "22/82"—today they will most often be told "682 down". The 6 refers to the last digit of 146 MHz, so that the display will read "146.82" (the output frequency), and the radio is set to transmit "down" 600 kHz on 146.22 MHz. Another way of describing a repeater frequency pair is to give the repeater's output frequency, along with the direction of offset ("+" or "plus" for an input frequency above

2875-474: A repeater. One type of SSTV repeater is activated by a station sending it a 1,750 Hz tone. The repeater sends K in morse code to confirm its activation, after which the station must start sending a picture within about 10 seconds. After reception, the received image is transmitted on the repeater's operation frequency. Another type is activated by the SSTV vertical synchronization signal (VIS code). Depending on

2990-479: A satellite may be of any type; the key distinction is that they are in orbit around the Earth, rather than terrestrial in nature. The three most common types of OSCARs are linear transponders, cross-band FM repeaters, and digipeaters (also referred to as pacsats). Amateur transponder repeaters are most commonly used on amateur satellites . A specified band of frequencies, usually having a bandwidth of 20 to 800 kHz

3105-436: A separate license and a call sign in another country, both of which have a mutually-agreed reciprocal licensing approvals. Reciprocal licensing requirements vary from country to country. Some countries have bilateral or multilateral reciprocal operating agreements allowing hams to operate within their borders with a single set of requirements. Some countries lack reciprocal licensing systems. Others use international bodies such as

3220-507: A signal, on different frequency, as they receive it. Instead, they operate in a store-and-forward manner, by receiving and then retransmitting on the same frequency after a short delay. These systems may not be legally classified as "repeaters", depending on the definition set by a country's regulator. For example, in the US, the FCC defines a repeater as an "amateur station that simultaneously retransmits

3335-423: A system may be better than others at rejecting nearby tone frequencies. CTCSS is an analog system. A later Digital-Coded Squelch (DCS) system was developed by Motorola under the trademarked name Digital Private Line (DPL). General Electric responded with the same system under the name of Digital Channel Guard (DCG). The generic name is CDCSS (Continuous Digital-Coded Squelch System). The use of digital squelch on

3450-504: A transmitter without the phase reversal feature is used, the squelch can remain unmuted for as long as the reed continues to vibrate—up to 1.5 seconds at the end of a transmission as it coasts to a stop (sometimes referred to as the "flywheel effect" or called "freewheeling"). In non-critical uses, CTCSS can also be used to hide the presence of interfering signals such as receiver-produced intermodulation. Receivers with poor specifications—such as scanners or low-cost mobile radios—cannot reject

3565-404: A unique identifying call sign , which must be used in all transmissions. Amateur operators must hold an amateur radio license which is obtained by passing a government test demonstrating adequate technical radio knowledge and legal knowledge of the host government's radio regulations. Radio amateurs are limited to a specific set of frequency bands, the amateur radio bands, allocated throughout

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3680-551: A wide range of interests. Many amateurs begin with a fascination with radio communication and then combine other personal interests to make pursuit of the hobby rewarding. Some of the focal areas amateurs pursue include radio contesting , radio propagation study, public service communication , technical experimentation , and computer networking . Hobbyist radio enthusiasts employ a variety of transmission methods for interaction . The primary modes for vocal communications are frequency modulation (FM) and single sideband (SSB). FM

3795-700: A year in the national capital and can be inordinately bureaucratic (for example in India) or challenging because some amateurs must undergo difficult security approval (as in Iran ). Currently, only Yemen and North Korea do not issue amateur radio licenses to their citizens. Some developing countries, especially those in Africa, Asia, and Latin America , require the payment of annual license fees that can be prohibitively expensive for most of their citizens. A few small countries may not have

3910-411: Is Nunavut , VY1 is Yukon , VY2 is Prince Edward Island , VO1 is Newfoundland , and VO2 is Labrador . CY is for amateurs operating from Sable Island (CY0) or St. Paul Island (CY9). Special permission is required to access either of these: from Parks Canada for Sable and Coast Guard for St. Paul. The last two or three letters of the call signs are typically the operator's choice (upon completing

4025-399: Is an amateur radio repeater station that relays slow-scan television signals. A typical SSTV repeater is equipped with a HF or VHF transceiver and a computer with a sound card , which serves as a demodulator/modulator of SSTV signals. SSTV repeaters are used by amateur radio operators for exchanging pictures. If two stations cannot copy each other, they can still communicate through

4140-410: Is assigned by a local frequency coordinating council. In the days of crystal-controlled radios, these pairs were identified by the last portion of the transmit (Input) frequency followed by the last portion of the receive (Output) frequency that the ham would put into the radio. Thus "three-four nine-four" (34/94) meant that hams would transmit on 146.34 MHz and listen on 146.94 MHz (while

4255-590: Is in the Turks and Caicos Islands, VP6xxx is on Pitcairn Island, VP8xxx is in the Falklands, and VP9xxx is in Bermuda. Online callbooks or call sign databases can be browsed or searched to find out who holds a specific call sign. An example of an online callbook is QRZ.com . Non-exhaustive lists of famous people who hold or have held amateur radio call signs have also been compiled and published. Many jurisdictions (but not in

4370-458: Is necessary. A repeater controller can be a hardware solution or even be implemented in software. Repeaters typically have a timer to cut off retransmission of a signal that goes too long. Repeaters operated by groups with an emphasis on emergency communications often limit each transmission to 30 seconds, while others may allow three minutes or even longer. The timer restarts after a short pause following each transmission, and many systems feature

4485-462: Is no longer tested in the U.S. Once the exam is passed, the FCC issues an Amateur Radio license which is valid for ten years. Studying for the exam is made easier because the entire question pools for all license classes are posted in advance. The question pools are updated every four years by the National Conference of VECs. Prospective amateur radio operators are examined on understanding of

4600-545: Is of international concern. Both the requirements for and privileges granted to a licensee vary from country to country, but generally follow the international regulations and standards established by the International Telecommunication Union and World Radio Conferences . All countries that license citizens to use amateur radio require operators to display knowledge and understanding of key concepts, usually by passing an exam. The licenses grant hams

4715-455: Is one type of in-band signaling that is used to reduce the annoyance of listening to other users on a shared two-way radio communication channel. It is sometimes referred to as tone squelch or PL for Private Line, a trademark of Motorola. It does this by adding a low frequency audio tone to the voice. Where more than one group of users is on the same radio frequency (called co-channel users ), CTCSS circuitry mutes those users who are using

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4830-522: Is recognized for its superior audio quality, whereas SSB is more efficient for long-range communication under limited bandwidth conditions. Radiotelegraphy using Morse code , also known as "CW" from " continuous wave ", is the wireless extension of landline (wired) telegraphy developed by Samuel Morse and dates to the earliest days of radio. Although computer-based (digital) modes and methods have largely replaced CW for commercial and military applications, many amateur radio operators still enjoy using

4945-435: Is repeated from one band to another. Transponders are not mode specific and typically no demodulation occurs. Any signal with a bandwidth narrower than the transponder's pass-band will be repeated; however, for technical reasons, use of modes other than SSB and CW are discouraged. Transponders may be inverting or non-inverting. An example of an inverting transponder would be a 70cm to 2m transponder which receives on

5060-419: Is similar to Voice over IP (VoIP), but augments two-way radio communications rather than telephone calls. EchoLink using VoIP technology has enabled amateurs to communicate through local Internet-connected repeaters and radio nodes, while IRLP has allowed the linking of repeaters to provide greater coverage area. Automatic link establishment (ALE) has enabled continuous amateur radio networks to operate on

5175-405: Is talking on the channel. Hand-held radios usually have a switch or push-button to monitor. Some modern radios have a feature called "Busy Channel Lockout", which will not allow the user to transmit as long as the radio is receiving another signal. A CTCSS decoder is based on a very narrow bandpass filter which passes the desired CTCSS tone. The filter's output is amplified and rectified, creating

5290-656: Is the Wireless Institute of Australia , formed in 1910; other notable societies are the Radio Society of Great Britain , the American Radio Relay League , Radio Amateurs of Canada , Bangladesh NGOs Network for Radio and Communication , the New Zealand Association of Radio Transmitters and South African Radio League . ( See Category:Amateur radio organizations ) An amateur radio operator uses

5405-684: Is typically found in the 70 cm (420–450 MHz) wavelength range, though there is also limited use on 33 cm (902–928 MHz), 23 cm (1240–1300 MHz) and shorter. These requirements also effectively limit the signal range to between 20 and 60 miles (30–100 km). Linked repeater systems, however, can allow transmissions of VHF and higher frequencies across hundreds of miles. Repeaters are usually located on heights of land or on tall structures, and allow operators to communicate over hundreds of miles using hand-held or mobile transceivers . Repeaters can also be linked together by using other amateur radio bands , landline , or

5520-415: Is used for digital ATV, due to narrow bandwidth needs and high loss tolerances. These DATV repeaters are more prevalent in Europe currently, partially because of the availability of DVB-S equipment. In addition, amateur radio satellites have been launched with the specific purpose of operating as space-borne amateur repeaters. The worldwide amateur satellite organization AMSAT designs and builds many of

5635-619: Is valid only in the country where it is issued or in another country that has a reciprocal licensing agreement with the issuing country. In some countries, an amateur radio license is necessary in order to purchase or possess amateur radio equipment. Amateur radio licensing in the United States exemplifies the way in which some countries award different levels of amateur radio licenses based on technical knowledge: three sequential levels of licensing exams (Technician Class, General Class, and Amateur Extra Class) are currently offered, which allow operators who pass them access to larger portions of

5750-428: The 33 or 23 cm band and output on 421.25 MHz or, sometimes, 426.25 MHz (within the 70 cm band ). These output frequencies happen to be the same as standard cable television channels 57 and 58, meaning that anyone with a cable-ready analog NTSC TV can tune them in without special equipment. There are also digital amateur TV repeaters that retransmit digital video signals. Frequently DVB-S modulation

5865-539: The Central Scotland FM Group and the Scottish Borders Repeater Group . The most basic repeater consists of an FM receiver on one frequency and an FM transmitter on another frequency usually in the same radio band, connected together so that when the receiver picks up a signal, the transmitter is keyed and rebroadcasts whatever is heard. In order to run the repeater a repeater controller

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5980-708: The Internet . Amateur radio satellites can be accessed, some using a hand-held transceiver ( HT ), even, at times, using the factory "rubber duck" antenna. Hams also use the moon , the aurora borealis , and the ionized trails of meteors as reflectors of radio waves. Hams can also contact the International Space Station (ISS) because many astronauts are licensed as amateur radio operators. Amateur radio operators use their amateur radio station to make contacts with individual hams as well as participate in round-table discussion groups or "rag chew sessions" on

6095-530: The Internet . Amateur radio is officially represented and coordinated by the International Amateur Radio Union (IARU), which is organized in three regions and has as its members the national amateur radio societies which exist in most countries. According to an estimate made in 2011 by the American Radio Relay League (the American national amateur radio society), two million people throughout

6210-527: The VHF 6-meter (50–54 MHz), 2-meter (144–148 MHz), 1.25-meter band (1 1 ⁄ 4 meters) (220–225 MHz) and the UHF 70 centimeter (420–450 MHz) bands, but can be used on almost any frequency pair above 28 MHz . In some areas, 33 centimeters (902–928 MHz) and 23 centimeters (1.24–1.3 GHz) are also used for repeaters. Note that different countries have different rules; for example, in

6325-479: The high frequency bands with global coverage. Other modes, such as FSK441 using software such as WSJT , are used for weak signal modes including meteor scatter and moonbounce communications. Fast scan amateur television has gained popularity as hobbyists adapt inexpensive consumer video electronics like camcorders and video cards in PCs . Because of the wide bandwidth and stable signals required, amateur television

6440-444: The radio spectrum , but within these bands are allowed to transmit on any frequency using a variety of voice, text, image, and data communications modes. This enables communication across a city, region, country, continent, the world, or even into space. In many countries, amateur radio operators may also send, receive, or relay radio communications between computers or transceivers connected to secure virtual private networks on

6555-495: The 432.000 MHz to 432.100 MHz frequencies and transmits on the 146.000 MHz to 146.100 MHz frequencies by inverting the frequency range within the band. In this example, a signal received at 432.001 MHz would be transmitted on 146.099 MHz. Voice signals using upper sideband modulation on the input would result in a LSB modulation on the output, and vice versa. "Phase 3D Satellite Primer" . Another class of repeaters do not simultaneously retransmit

6670-446: The 500 Hz to 1 kHz (10–20%) range. The ability of a receiver to mute the audio until it detects a carrier with the correct CTCSS tone is called decoding . Receivers are equipped with features to allow the CTCSS "lock" to be disabled. On a base station console, a microphone may have a split push-to-talk button. Pressing one half of the button, (often marked with a speaker icon or the letters "MON", short for "MONitor") disables

6785-649: The Amateur Radio spectrum and more desirable (shorter) call signs. An exam, authorized by the Federal Communications Commission (FCC), is required for all levels of the Amateur Radio license. These exams are administered by Volunteer Examiners, accredited by the FCC-recognized Volunteer Examiner Coordinator (VEC) system. The Technician Class and General Class exams consist of 35 multiple-choice questions, drawn randomly from

6900-404: The CTCSS decoder and reverts the receiver to hearing any signal on the channel. This is called the monitor function. There is sometimes a mechanical interlock: the user must push down and hold the monitor button or the transmit button is locked and cannot be pressed. This interlock option is referred to as compulsory monitor before transmit (the user is forced to monitor by the hardware design of

7015-521: The CW mode—particularly on the shortwave bands and for experimental work, such as Earth–Moon–Earth communication , because of its inherent signal-to-noise ratio advantages. Morse, using internationally agreed message encodings such as the Q code , enables communication between amateurs who speak different languages. It is also popular with homebrewers and in particular with "QRP" or very-low-power enthusiasts, as CW-only transmitters are simpler to construct, and

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7130-571: The Federal Communications Commission regulates the Amateur Radio Service. The United States Code of Federal Regulations Title 47 CFR, Part 97, which are the laws in which the Amateur Radio Service is regulated clearly states the definition of Frequency Coordinator. The purpose of coordinating a repeater or frequency is to reduce harmful interference to other fixed operations. Coordinating a repeater or frequency with other fixed operations demonstrates good engineering and amateur practice. In

7245-580: The ITU convention for the numeral. In the United Kingdom the original calls G0xxx, G2xxx, G3xxx, G4xxx, were Full (A) License holders along with the last M0xxx full call signs issued by the City & Guilds examination authority in December 2003. Additional Full Licenses were originally granted to (B) Licenses with G1xxx, G6xxx, G7xxx, G8xxx and 1991 onward with M1xxx call signs. The newer three-level Intermediate License holders are assigned 2E0xxx and 2E1xxx, and

7360-499: The ITU's Table of Frequency Allocations . These allocations may only apply to a group of countries. Amateur radio The amateur radio service ( amateur service and amateur-satellite service ) is established by the International Telecommunication Union (ITU) through the Radio Regulations . National governments regulate technical and operational characteristics of transmissions and issue individual station licenses with

7475-499: The Isle of Man, "GJ" & "MJ" are Jersey and "GU" & "MU" are Guernsey. Intermediate licence call signs are slightly different. They begin 2#0 and 2#1 where the # is replaced with the country letters as above. For example "2M0" and "2M1" are Scotland, "2W0" and "2W1" are Wales and so on. The exception however is for England. The letter "E" is used, but only in intermediate-level call signs. For example "2E0" & "2E1" are used whereas

7590-455: The Organization of American States to facilitate licensing reciprocity. When traveling abroad, visiting amateur operators must follow the rules of the country in which they wish to operate. Some countries have reciprocal international operating agreements allowing hams from other countries to operate within their borders with just their home country license. Other host countries require that

7705-530: The RF spectrum, usually allowing choice of an effective frequency for communications across a local, regional, or worldwide path. The shortwave bands, or HF , are suitable for worldwide communication, and the VHF and UHF bands normally provide local or regional communication, while the microwave bands have enough space, or bandwidth , for amateur television transmissions and high-speed computer networks . In most countries, an amateur radio license grants permission to

7820-428: The UK & Europe) may issue specialty vehicle registration plates to licensed amateur radio operators. The fees for application and renewal are usually less than the standard rate for specialty plates. In most administrations, unlike other RF spectrum users, radio amateurs may build or modify transmitting equipment for their own use within the amateur spectrum without the need to obtain government certification of

7935-419: The UK mains power line frequency; an inadequately smoothed power supply may cause unwanted squelch opening (this is true in many other areas that use 50 Hz power). Tones typically come from one of three series as listed below along with the two character PL code used by Motorola to identify tones. The most common set of supported tones is a set of 39 tones including all tones with Motorola PL codes, except for

8050-493: The UK, the frequency allocations for repeaters are managed by the Emerging Technology Co-ordination Committee (ETCC) of the Radio Society of Great Britain and licensed by Ofcom , the industry regulator for communications in the UK. Each repeater has a NOV (Notice of Variation) licence issued to a particular amateur radio callsign (this person is normally known as the "repeater keeper") thus ensuring

8165-552: The United Kingdom and Australia, have begun requiring a practical assessment in addition to the written exams in order to obtain a beginner's license, which they call a Foundation License. In most countries, an operator will be assigned a call sign with their license. In some countries, a separate "station license" is required for any station used by an amateur radio operator. Amateur radio licenses may also be granted to organizations or clubs. In some countries, hams were allowed to operate only club stations. An amateur radio license

8280-559: The United States, the two-meter band is 144–148 MHz, while in the United Kingdom (and most of Europe) it is 144–146 MHz. Repeater frequency sets are known as "repeater pairs", and in the ham radio community most follow ad hoc standards for the difference between the two frequencies, commonly called the offset . In the USA two-meter band, the standard offset is 600 kHz (0.6 MHz), but sometimes unusual offsets, referred to as oddball splits , are used. The actual frequency pair used

8395-763: The air. Some join in regularly scheduled on-air meetings with other amateur radio operators, called " nets " (as in "networks"), which are moderated by a station referred to as "Net Control". Nets can allow operators to learn procedures for emergencies, be an informal round table, or cover specific interests shared by a group. Amateur radio operators, using battery- or generator-powered equipment, often provide essential communications services when regular channels are unavailable due to natural disaster or other disruptive events . Many amateur radio operators participate in radio contests, during which an individual or team of operators typically seek to contact and exchange information with as many other amateur radio stations as possible in

8510-433: The amateur radio field, which imposes limits on achievable intermodulation and adjacent-channel performance. Family Radio Service (FRS), PMR446 and other consumer-grade radios often include a CTCSS feature called "Interference Eliminator Codes", "sub-channels", "privacy tones", or "privacy codes". These do not afford privacy or security, but serve only to reduce annoying interference by other users or other noise sources;

8625-470: The amateur satellites, which are also known as OSCARs . Several satellites with amateur radio equipment on board have been designed and built by universities around the world. Also, several OSCARs have been built for experimentation. For example, NASA and AMSAT coordinated the release of SuitSat which was an attempt to make a low cost experimental satellite from a discarded Russian spacesuit outfitted with amateur radio equipment. The repeaters on board

8740-508: The basic Foundation License holders are granted call signs M3xxx, M6xxx or M7xxx. Instead of using numbers, in the UK the second letter after the initial 'G' or 'M' identifies the station's location; for example, a call sign G7OOE becomes GM7OOE and M0RDM becomes MM0RDM when that license holder is operating a station in Scotland. Prefix "GM" & "MM" are Scotland, "GW" & "MW" are Wales, "GI" & "MI" are Northern Ireland, "GD" & "MD" are

8855-431: The best quieting (strongest) signal, and the output of the selector will actually trigger the central repeater transmitter. A properly adjusted voting system can switch many times a second and can actually "assemble" a multi-syllable word using a different satellite receiver for each syllable. Such a system can be used to widen coverage to low power mobile radios or handheld radios that otherwise would not be able to key up

8970-446: The call signs beginning G or M for foundation and full licenses never use the "E". In the United States, for non-vanity licenses, the numeral indicates the geographical district the holder resided in when the license was first issued. Prior to 1978, US hams were required to obtain a new call sign if they moved out of their geographic district. In Canada, call signs start with VA, VE, VY, VO, and CY. Call signs starting with 'V' end with

9085-651: The central location, but can receive the signal from the central location without an issue. Voting systems require no knowledge or effort on the part of the user – the system just seems to have better-than-average handheld coverage. Repeaters may also be connected over the Internet using voice over IP ( VoIP ) techniques. VoIP links are a convenient way to connecting distant repeaters that would otherwise be unreachable by VHF/UHF radio propagation. Popular VoIP amateur radio network protocols include AllStarLink/HamVoIP, D-STAR , Echolink , IRLP , WIRES and eQSO . Digital Mobile Radio (DMR), D-STAR, Fusion, P25 and NXDN all have

9200-501: The classroom to teach English, map skills, geography, math, science, and computer skills. The term "ham" was first a pejorative term used in professional wired telegraphy during the 19th century, to mock operators with poor Morse code -sending skills (" ham-fisted "). This term continued to be used after the invention of radio and the proliferation of amateur experimentation with wireless telegraphy; among land- and sea-based professional radio operators, "ham" amateurs were considered

9315-755: The early 20th century. The First Annual Official Wireless Blue Book of the Wireless Association of America , produced in 1909, contains a list of amateur radio stations. This radio callbook lists wireless telegraph stations in Canada and the United States, including 89 amateur radio stations. As with radio in general, amateur radio was associated with various amateur experimenters and hobbyists. Amateur radio enthusiasts have significantly contributed to science , engineering , industry, and social services . Research by amateur operators has founded new industries, built economies, empowered nations, and saved lives in times of emergency. Ham radio can also be used in

9430-428: The end of a transmission to eliminate the squelch crash or squelch tail. This is common with General Electric Mobile Radio and Motorola systems. When the user releases the push-to-talk button the CTCSS tone does a phase shift for about 200 milliseconds. In older systems, the tone decoders used mechanical reeds to decode CTCSS tones. When audio at a resonant pitch was fed into the reed, it would resonate, which would turn on

9545-496: The equipment itself). On mobile radios , the microphone is usually stored in a hang-up clip or a hang-up box containing a microphone clip. When the user pulls the microphone out of the hang-up clip to make a call, a switch in the clip (box) forces the receiver to revert to conventional carrier squelch mode ("monitor"). Some designs relocate the switch into the body of the microphone itself. In hand-held radios, an LED indicator may glow green, yellow, or orange to indicate another user

9660-408: The equipment. Licensed amateurs can also use any frequency in their bands (rather than being allocated fixed frequencies or channels) and can operate medium-to-high-powered equipment on a wide range of frequencies so long as they meet certain technical parameters including occupied bandwidth, power, and prevention of spurious emission . Radio amateurs have access to frequency allocations throughout

9775-423: The help of a mentor, teacher, or friend. In North America, established amateurs who help newcomers are often referred to as "Elmers", as coined by Rodney Newkirk, W9BRD, within the ham community. In addition, many countries have national amateur radio societies which encourage newcomers and work with government communications regulation authorities for the benefit of all radio amateurs. The oldest of these societies

9890-818: The human ear-brain signal processing system can pull weak CW signals out of the noise where voice signals would be totally inaudible. A similar "legacy" mode popular with home constructors is amplitude modulation (AM), pursued by many vintage amateur radio enthusiasts and aficionados of vacuum tube technology. Demonstrating a proficiency in Morse code was for many years a requirement to obtain an amateur license to transmit on frequencies below 30 MHz. Following changes in international regulations in 2003, countries are no longer required to demand proficiency. The United States Federal Communications Commission , for example, phased out this requirement for all license classes on 23 February 2007. Modern personal computers have encouraged

10005-570: The key concepts of electronics, radio equipment, antennas, radio propagation , RF safety, and the radio regulations of the government granting the license. These examinations are sets of questions typically posed in either a short answer or multiple-choice format. Examinations can be administered by bureaucrats , non-paid certified examiners, or previously licensed amateur radio operators. The ease with which an individual can acquire an amateur radio license varies from country to country. In some countries, examinations may be offered only once or twice

10120-417: The license holder to own, modify, and operate equipment that is not certified by a governmental regulatory agency. This encourages amateur radio operators to experiment with home-constructed or modified equipment. The use of such equipment must still satisfy national and international standards on spurious emissions . Amateur radio operators are encouraged both by regulations and tradition of respectful use of

10235-437: The licensing authority has a single point of contact for that particular repeater. Each repeater in the UK is normally supported by a repeater group composed of local amateur radio enthusiasts who pay a nominal amount e.g. £10–15 a year each to support the maintenance of each repeater and to pay for site rents, electricity costs etc. Repeater groups do not receive any central funding from other organisations. Such groups include

10350-571: The licensing test, the ham writes three most-preferred options). Two-letter call sign suffixes require a ham to have already been licensed for 5 years. Call signs in Canada can be requested with a fee. Also, for smaller geopolitical entities, the numeral may be part of the country identification. For example, VP2xxx is in the British West Indies, which is subdivided into VP2Exx Anguilla, VP2Mxx Montserrat, and VP2Vxx British Virgin Islands. VP5xxx

10465-403: The most recent EIA/ TIA -603-E; the CTCSS tones also may be listed in manufacturers instruction, maintenance or operational manuals. Some systems use non-standard tones. The NATO Military radios use 150.0 Hz, and this can be found in the user manuals for the radios. Some areas do not use certain tones. For example, the tone of 100.0 Hz is avoided in the United Kingdom since this is twice

10580-436: The output frequency, "−" or "minus" for a lower frequency) with the assumption that the repeater uses the standard offset for the band in question. For instance, a 2-meter repeater might be described as "147.36 with a plus offset", meaning that the repeater transmits on 147.36 MHz and receives on 147.96 MHz, 600 kHz above the output frequency. Services provided by a repeater may include an autopatch connection to

10695-892: The privilege to operate in larger segments of the radio frequency spectrum, with a wider variety of communication techniques, and with higher power levels relative to unlicensed personal radio services (such as CB radio , FRS , and PMR446 ), which require type-approved equipment restricted in mode, range, and power. Amateur licensing is a routine civil administrative matter in many countries. Amateurs therein must pass an examination to demonstrate technical knowledge, operating competence, and awareness of legal and regulatory requirements, in order to avoid interfering with other amateurs and other radio services. A series of exams are often available, each progressively more challenging and granting more privileges: greater frequency availability, higher power output, permitted experimentation, and, in some countries, distinctive call signs. Some countries, such as

10810-492: The public safety agencies numbers programmed as speed-dial numbers. Repeater coordination is not required by the Federal Communications Commission, nor does the FCC regulate, certify or otherwise regulate frequency coordination for the Amateur Radio Bands. Amateur Radio Repeater Coordinators or coordination groups are all volunteers and have no legal authority to assume jurisdictional or regional control in any area where

10925-622: The receiver picks up for a set length of time (usually 30 seconds or less), then plays back the recording over the transmitter on the same frequency. A common name is a "parrot" repeater. Another form of repeater used in amateur packet radio , a form of digital computer-to-computer communications, is dubbed "digipeater" (for DIGItal rePEATER). Digipeaters are often used for activities and modes such as packet radio, Automatic Packet Reporting System , and D-STAR 's digital data mode. Also commercial digital modes such as DMR, P25 and NXDN. Some modes are full duplex and internet linked. An SSTV repeater

11040-421: The repeated speech audio for a selectable number of milliseconds before it is retransmitted. During this fixed delay period (the amount of which is adjusted during installation, then locked down), the CTCSS decoder has enough time to recognize the right tone. This way the problem with lost syllables at the beginning of a transmission can be overcome without having to use higher frequency tones. In early systems, it

11155-428: The repeater would do the opposite, listening on 146.34 and transmitting on 146.94). In areas with many repeaters, "reverse splits" were common (i.e., 94/34), to prevent interference between systems. Since the late 1970s, the use of synthesized, microprocessor-controlled radios, and widespread adoption of standard frequency splits have changed the way repeater pairs are described. In 1980, a ham might have been told that

11270-688: The repeaters are made via radio (usually on a different frequency from the published transmitting frequency) for maximum reliability. Some networks have a feature to allow the user being able to turn additional repeaters and links on or off on the network. This feature is typically done with DTMF tones to control the network infrastructure. Such a system allows coverage over a wide area, enabling communication between amateurs often hundreds of miles (several hundred km) apart. These systems are used for area or regional communications, for example in Skywarn nets, where storm spotters relay severe weather reports. All

11385-430: The same time. This avoids the use of complex duplexers to achieve the required rejection for same band repeating. Most modern dual-band amateur transceivers are capable of cross-band repeat. Amateur television (ATV) repeaters are used by amateur radio operators to transmit full motion video. The bands used by ATV repeaters vary by country, but in the US a typical configuration is as a cross-band system with an input on

11500-434: The software it uses (MMSSTV, JVComm32, MSCAN, for example), an SSTV repeater typically operates in common SSTV modes. Repeaters may be linked together in order to form what is known as a linked repeater system or linked repeater network . In such a system, when one repeater is keyed-up by receiving a signal, all the other repeaters in the network are also activated and will transmit the same signal. The connections between

11615-486: The speaker audio. The end-of-transmission phase reversal (called "Reverse Burst" by Motorola (and trademarked by them) and "Squelch Tail Elimination" or "STE" by GE ) caused the reed to abruptly stop vibrating which would cause the receive audio to instantly mute. Initially, a phase shift of 180 degrees was used, but experience showed that a shift of ±120 to 135 degrees was optimal in halting the mechanical reeds. These systems often have audio muting logic set for CTCSS only. If

11730-497: The spectrum to use as little power as possible to accomplish the communication. This is to minimise interference or EMC to any other device. Although allowable power levels are moderate by commercial standards, they are sufficient to enable global communication. Lower license classes usually have lower power limits; for example, the lowest license class in the UK (Foundation licence) has a limit of 10 W. Power limits vary from country to country and between license classes within

11845-478: The strong signals present in urban environments. The interference will still be present and may block the receiver, but the decoder will prevent it from being heard. It will still degrade system performance but the user will not have to hear the noises produced by receiving the interference. CTCSS is commonly used in VHF and UHF amateur radio operations for this purpose. Wideband and extremely sensitive radios are common in

11960-447: The system start decoding after they sense a carrier signal then recognize the tone on the carrier as valid. Any distortion on the encoded tone will also affect the decoding time. Engineered systems often use tones in the 127.3 Hz to 162.2 Hz range to balance fast decoding with keeping the tones out of the audible part of the receive audio. Most amateur radio repeater controller manufacturers offer an audio delay option—this delays

12075-427: The time lag can be significant. The lower tone may cause one or two syllables to be clipped before the receiver audio is unmuted (is heard). This is because receivers are decoding in a chain. The repeater receiver must first sense the carrier signal on the input, then decode the CTCSS tone. When that occurs, the system transmitter turns on, encoding the CTCSS tone on its carrier signal (the output frequency). All radios in

12190-414: The tones 8Z, 9Z, and 0Z (zero-Z). The lowest series has adjacent tones that are roughly in the harmonic ratio of 2 to 1 (≈1.035265), while the other two series have adjacent tones roughly in the ratio of 10 to 1 (≈1.035142). An example technical description can be found in a Philips technical information sheet about their CTCSS products. Some professional systems use a phase-reversal of the CTCSS tone at

12305-543: The tower and one antenna. Most repeaters are remotely controlled through the use of audio tones on a control channel. A cross-band repeater (also sometimes called a replexer), is a repeater that retransmits a specific mode on a frequency in one band to a specific mode on a frequency in a different band. This technique allows for a smaller and less complex repeater system. Repeating signals across widely separated frequency bands allows for simple filters to be used to allow one antenna to be used for both transmit and receive at

12420-409: The transmission of another amateur station on a different channel or channels." (CFR 47 97.205(b)) Store-and-forward systems neither retransmit simultaneously, nor use a different channel. Thus, they must be operated under different rules than more conventional repeaters. A type of system known as a simplex repeater uses a single transceiver and a short-duration voice recorder, which records whatever

12535-437: The transmit and receive signals over a single antenna. The duplexer is a device which prevents the repeater's high-power transmitter (on the output frequency) from drowning out the users' signal on the repeater receiver (on the input frequency). A diplexer allows two transmitters on different frequencies to use one antenna, and is common in installations where one repeater on 2 m and a second on 440 MHz share one feedline up

12650-513: The transmit button is pressed. The tone is transmitted at a low level simultaneously with the voice. This is called CTCSS encoding . CTCSS tones range from 67 to 257  Hz . The tones are usually referred to as sub-audible tones . In an FM two-way radio system, CTCSS encoder levels are usually set for 15% of system deviation . For example, in a 5 kHz deviation system, the CTCSS tone level would normally be set to 750 Hz deviation. Engineered systems may call for different level settings in

12765-442: The use of digital modes such as radioteletype (RTTY) which previously required cumbersome mechanical equipment. Hams led the development of packet radio in the 1970s, which has employed protocols such as AX.25 and TCP/IP . Specialized digital modes such as PSK31 allow real-time, low-power communications on the shortwave bands but have been losing favor in place of newer digital modes such as FT8 . Radio over IP , or RoIP,

12880-465: The user has to know is which channel to use in which area. In order to get better receive coverage over a wide area, a similar linked setup can also be done with what is known as a voted receiver system . In a voted receiver, there are several satellite receivers set up to receive on the same frequency (the one that the users transmit on). All of the satellite receivers are linked to a voting selector panel that switches from receiver to receiver based on

12995-461: The visiting ham apply for a formal permit, or even a new host country-issued license, in advance. The reciprocal recognition of licenses frequently not only depends on the involved licensing authorities, but also on the nationality of the bearer. As an example, in the US, foreign licenses are recognized only if the bearer does not have US citizenship and holds no US license (which may differ in terms of operating privileges and restrictions). Conversely,

13110-627: The world are regularly involved with amateur radio. About 830,000 amateur radio stations are located in IARU Region 2 (the Americas) followed by IARU Region 3 (South and East Asia and the Pacific Ocean) with about 750,000 stations. A significantly smaller number, about 400,000, are located in IARU Region 1 (Europe, Middle East, CIS , Africa). The origins of amateur radio can be traced to the late 19th century, but amateur radio as practised today began in

13225-488: Was common to avoid the use of adjacent tones. On channels where every available tone is not in use, this is good engineering practice. For example, an ideal would be to avoid using 97.4 Hz and 100.0 Hz on the same channel. The tones are so close that some decoders may periodically false trigger. The user occasionally hears a syllable or two of co-channel users on a different CTCSS tone talking. As electronic components age, or through production variances, some radios in

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