Morse code

Morse code is a type of character encoding that transmits telegraphic information using rhythm. Morse code uses a standardized sequence of short and long elements to represent the letters, numerals, punctuation and special characters of a given message. The short and long elements can be formed by sounds, marks, or pulses, in on off keying and are commonly known as "dots" and "dashes" or "dits" and "dahs". The speed of Morse code is measured in words per minute (WPM) or characters per minute, while fixed-length data forms of telecommunication transmission are usually measured in baud or bps.

Originally created for Samuel F. B. Morse's electric telegraph in the early 1840s, Morse code was also extensively used for early radio communication beginning in the 1890s. For the first half of the twentieth century, the majority of high-speed international communication was conducted in Morse code, using telegraph lines, undersea cables, and radio circuits. However, the variable length of the Morse characters made it hard to adapt to automated circuits, so for most electronic communication it has been replaced by machine readable formats, such as Baudot code and ASCII.

The most popular current use of Morse code is by amateur radio operators, although it is no longer a requirement for amateur licensing in many countries. In the professional field, pilots and air traffic controllers are usually familiar with Morse code and require a basic understanding. Navigational aids in the field of aviation, such as VORs and NDBs, constantly transmit their identity in Morse code. Morse code is designed to be read by humans without a decoding device, making it useful for sending automated digital data in voice channels. For emergency signaling, Morse code can be sent by way of improvised sources that can be easily "keyed" on and off, making Morse code one of the most versatile methods of telecommunication in existence.

This photograph shows the receivers and transceivers used in an amateur radio station

Singapore Amateur Radio Transmitting Society

The Singapore Amateur Radio Transmitting Society (SARTS) is a non-profit organization for amateur radio enthusiasts in Singapore. The organization's primary mission is to popularize and promote amateur radio in Singapore. SARTS sponsors amateur radio operating awards and operates special event stations on a regular basis. One membership benefit of the organization is a QSL bureau for members who regularly make communications with amateur radio operators in other countries.^[1] SARTS is the member society representing Singapore in the International Amateur Radio Union.^[2]

Abbreviation	SARTS
Type	Non-profit organization
Purpose/focus	Advocacy, Education
Location	Singapore
Region served	Singapore
Official languages	English
President	Darryl Ee 9V1DE
Affiliations	International Amateur Radio Union
Website	http://www.sarts.org.sg/

Malaysian Amateur Radio Transmitters' Society

The Malaysian Amateur Radio Transmitters' Society (MARTS) is a non-profit organization for amateur radio enthusiasts in Malaysia. MARTS was founded in 1952. The organization's primary mission is to popularize and promote amateur radio in Malaysia. One membership benefit of the organization is a QSL bureau for members who regularly make communications with amateur radio operators in other countries.^[2] MARTS is the member society representing Malaysia in the International Amateur Radio Union.^[3]

Abbreviation	MARTS
Formation	1952[1]
Type	Non-profit organization
Purpose/focus	Advocacy, Education
Location	Kuala Lumpur, Malaysia
Region served	Malaysia
Official languages	English, Malay
President	Muhammad bin Ismail 9W2IL
Affiliations	International Amateur Radio Union
Website	http://www.marts.org.my/

Organisasi Amatir Radio Indonesia

The Organisasi Amatir Radio Indonesia (ORARI) (n English, Amateur Radio Organization of Indonesia) is a national non-profit organization for amateur radio enthusiasts in Indonesia. According to a 2000 census compiled by the International Amateur Radio Union, Indonesia has the thirteenth-largest population of amateur radio operators in the world.^[1] A key membership benefit of the ARI is a QSL bureau for those Indonesian amateur radio operators in regular communications with other amateur radio operators in foreign countries. The ORARI represents the interests of Indonesian amateur radio operators before Indonesian and international regulatory authorities. ORARI is the national member society representing Indonesia in the International Amateur Radio Union.^[2]

Abbreviation	ORARI
Type	Non-profit organization
Purpose/focus	Advocacy, Education
Headquarters	Jakarta, Indonesia
Region served	Indonesia
Official languages	Indonesian
President	Sutiyoso YB0ST
Affiliations	International Amateur Radio Union
Website	http://www.orari.or.id/

FM broadcasting

Edwin Armstrong presented his paper: "A Method of Reducing Disturbances in Radio Signaling by a System of Frequency Modulation", which first described FM radio, before the New York section of the Institute of Radio Engineers on November 6, 1935. The paper was published in 1936. ^[3]

As the name implies, wideband FM (W-FM) requires a wider signal bandwidth than amplitude modulation by an equivalent modulating signal, but this also makes the signal more robust against noise and interference. Frequency modulation is also more robust against simple signal amplitude fading phenomena. As a result, FM was chosen as the modulation standard for high frequency, high fidelity radio transmission: hence the term "FM radio" (although for many years the BBC called it "VHF radio", because commercial FM broadcasting uses a well-known part of the VHF band; in certain countries, expressions referencing the more familiar wavelength notion are still used in place of the more abstract modulation technique name).

FM receivers employ a special detector for FM signals and exhibit a phenomenon called capture effect, where the tuner is able to clearly receive the stronger of two stations being broadcast on the same frequency. Problematically however, frequency drift or lack of selectivity may cause one station or signal to be suddenly overtaken by another on an adjacent channel. Frequency drift typically constituted a problem on very old or inexpensive receivers, while inadequate selectivity may plague any tuner.

An FM signal can also be used to carry a stereo signal: see FM stereo. However, this is done by using multiplexing and demultiplexing before and after the FM process. The rest of this article ignores the stereo multiplexing and demultiplexing process used in "stereo FM", and concentrates on the FM modulation and demodulation process, which is identical in stereo and mono processes.

A high-efficiency radio-frequency switching amplifier can be used to transmit FM signals (and other constant-amplitude signals). For a given signal strength (measured at the receiver antenna), switching amplifiers use less battery power and typically cost less than a linear amplifier. This gives FM another advantage over other modulation schemes that require linear amplifiers, such as AM and QAM.

Practical Wireless

Practical Wireless is a British radio and electronics magazine, now published monthly by PW Publishing of Broadstone, Dorset. The current editor (2009) is Rob Mannion.

The magazine was founded in 1932 (as a supplement) by FJ Camm (brother of Sydney Camm), of George Newnes Publishers. It became an independent weekly in that year, then monthly in 1941 (due to wartime paper shortages). Camm was editor until his death in 1959: it was often referred to affectionately as 'Camm's comic'.

Clive Sinclair (later Sir Clive Sinclair) was, for a period, the assistant editor for Practical Wireless, after writing articles for them since his school days. Note from present Editor Rob Mannion G3XFD/EI5IW: Although Clive Sinclair was associated with PW (he advertised his products extensively in the magazine) there is no evidence of him ever actually being on the staff. Despite extensive enquiries, including writing to Sir Clive (no reply to my letter) I have not been able to confirm that he worked for IPC Magazines (who took over from George Newnes the original publishers).

The magazine covered mainly wireless (radio) topics. In 1964, the non-wireless articles were 'spun off' as a separate magazine Practical Electronics (now published as Everyday Practical Electronics by Wimborne Publishing Ltd, Ferndown, Dorset). In the early 1980s, Practical Wireless became dedicated entirely to amateur radio.

CQ Amateur Radio

CQ Amateur Radio (also known simply as CQ or CQ magazine) (OCLC 310821852) is a magazine for amateur radio enthusiasts. The magazine has a worldwide readership base for its English language edition. A Spanish language edition is published in Spain with some translations of articles from the English language edition and some original European content. Since its inception in 1945, CQ Communication, Inc. has published over thirty paperback books that address most major aspects of the amateur radio hobby, which are frequently promoted through the magazine.

CQ Amateur Radio is not associated with the similarly-named Japanese magazine CQ ham radio.

73 (magazine)

73 Magazine (also known as 73 Amateur Radio Today) (OCLC 22239204) was a United States-based amateur radio magazine that was published from 1960 to 2003. It was known for its strong emphasis on technical articles and for the lengthy editorials in each issue by its founder and publisher, Wayne Green. The magazine title, 73, means "best regards" in amateur radio lingo.

Amateur radio license

In all countries, amateur radio operators are required to pass a licensing exam displaying knowledge and understanding of key concepts^[18]. In response, hams are granted operating privileges in larger segments of the radio frequency spectrum using a wide variety of communication techniques with higher power levels permitted. This practice is in contrast to unlicensed personal radio services such as CB radio, Multi-Use Radio Service, or Family Radio Service/PMR446 that require type-approved equipment restricted in frequency range and power.

In many countries, amateur licensing is a routine civil administrative matter. Amateurs are required to pass an examination to demonstrate technical knowledge, operating competence and awareness of legal and regulatory requirements in order to avoid interference with other amateurs and other radio services. There are often a series of exams available, each progressively more challenging and granting more privileges in terms of frequency availability, power output, permitted experimentation, and in some countries, distinctive callsigns. Some countries such as the United Kingdom and Australia have begun requiring a practical training course in addition to the written exams in order to obtain a beginner's license, called a Foundation License.

Amateur radio licensing in the United States serves as an example of the way 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 the Amateur Radio spectrum and more desirable callsigns.