Updated : November 17, 2015

Introduction to Ham Radio

Ever since Marconi transmitted the first radio signals across the Atlantic Ocean, about one hundred years ago, Amateur Radio experimenters have played an important role in the development of radio communication. In the first part of the twentieth century, radio experimentation by members of the public was barely tolerated by the authorities and Radio Amateurs were confined to bands which were considered 'useless' for commercial or public use.


Guglielmo Marconi at Signal Hill, St. John's, Newfoundland, just after receiving the first wireless signal to cross the Atlantic Ocean on the 12th of December 1901. It consisted of the Morse letter 'S' (dot dot dot) transmitted from his wireless station at Poldhu, Cornwall, England.

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In spite of this restrictive policy, Amateur or Ham Radio has grown into a recognized leisure activity for thousands and thousands of radio enthusiasts around the world, in touch with each other via invisible radio waves using their own radio radio transmitting and receiving equipment. Especially after World War II Amateur Radio was greatly stimulated by the vast amount of surplus radio equipment that became available. One of the most fascinating aspects of Amateur Radio, is making radio contacts with other Radio Amateurs all over the world, sometimes in remote locations.

Worldwide there are more than two million licensed radio enthusiasts spread across virtually every country, who are free to operate from the comfort of their own homes. Age, profession, nationality, political and ethnic barriers are non- existent, thus promoting international friendship and understanding. Amateur radio can be enjoyed by young and old, male and female and even the most severely disabled can make friends around the world from their own home. Very often friendships for life develop between Radio Amateurs, carrying out experiments with various, and often advanced, communication techniques.

After being used extensively by the allied forces during World War II, the famous Wireless Set 19 was among the vast amount of war surplus equipment that became available and greatly stimulated Amateur Radio during the postwar period.

WS 19-set
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These days Ham Radio is widely accepted in recognition of its leading role in the development of new and advanced radio telecommunication techniques. In many countries, Radio Amateurs have founded societies which provide forums to exchange ideas and also to protect the interests of the Radio Amateur Service.

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Not familiar with the essentials of radio communication, the attraction of Amateur Radio might be questionable for many in our present society in which worldwide instant communication has become a public property, thanks to the Internet, cellular telephones and satellite communication.

Asking a Radio Amateur why he or she is spending many hours with a radio to contact someone far away instead of using the Internet or any other means of modern telecommunication, is probably like asking a sailor why he or she is using a sailing boat instead of motor vessel. Or asking a mountaineer why he or she isn't using the cable-lift as a quick and comfortable means to get to the top. Why are some commercial airline pilots soaring the skies for pleasure with a glider plane? It probably has to do with the human desire to have control over natural elements and to explore the bounds of possibilities.

My ham radio equipment in 1966
My ham radio equipment in 1966

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Like sailors making use of the effects of winds and tides, or glider pilots staying in the air for hours thanks to thermal activities in the atmosphere, Radio Amateurs, like professional radio users, depend on the capability of invisible radio waves to find their way through the earth's atmosphere and space. Unlike cables, the atmosphere is a rather complex and irregular transmission medium for a great deal affected by solar radiation. For that reason the properties of the radio transmission medium is subject to diurnal and seasonal variations as well as an 11 year solar cycle. In addition to the sun there are some other natural phenomena that affect and support radio wave propagation, like Meteor Showers and Aurora (polar lights).


Aurora or Polar Lights reflect radio waves enabling Radio Amateurs to make contacts over relatively large distances using the higher frequency bands. This unique picture taken from a spacecraft during a space weather storm on October 22nd, 2001 shows the Northern and Southern Lights (Aurora Borealis and Aurora Australis) brightening at the same time at opposite ends of the earth. Never before were both auroral ovals, appearing to be a mirror image of each other, seen and captured on film simultaneously with such clarity.

Photo : NASA

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HF Dipole

A thorough understanding of the way natural phenomena affect radio wave propagation enables an experienced Ham to predict at what time radio contact with a particular location might be established. This is especially of great importance to those Hams aiming at establishing contacts with as many countries as practically possible. But even with that knowledge, it might be difficult to establish contacts with certain countries, like those with a limited number of Hams or with restrictions on the use of radio transmitting equipment imposed by the government.

In their endeavour to provide radio communication with all parts of the world, Radio Amateurs organize expeditions to those "hard to get" countries and other remote and exotic places. In addition to highly reliable equipment, creativity and well developed organizing talent are required for those DX-peditions (DX is the abbreviation for long distance communication).

One of those many DX-peditions took place from March 1 to March 8, 2000 when a team of 13 radio amateurs operated from Clipperton Island, an uninhabited coral atoll, about 8 km in circumference and located 1,120 km southwest of Mexico, in the Pacific Ocean. Using callsign FO0AAA, the team logged over 75.000 contacts, easily placing it in the top 10 DX-peditions of all time.

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Establishing contacts with those DX-peditions is also a real challenge for those staying at home, anxious to contact such a rare new country within the limited duration of a DX-pedition. It requires the right combination of operating skills and knowledge of radio wave propagation to know how and when to beat the competition of thousands of fellow-hams worldwide trying to achieve the same goal: adding a new rare country to their records and to get the QSL card of that DXpedition as a concrete proof. View the QSL cards of some of the DXpeditions I managed to work on the HF bands with my simple short balcony wire antenna.

Coaxial Cable

Many hams pursue a facet of the hobby called "Awards chasing" in recognition of their achievements. While there are literally thousands of awards offered by hundreds of Amateur Radio organizations, the DX Century Club (DXCC) award is probably the most prestigious and sought-after award world wide. This award, sponsered by the American Radio Relay League (ARRL), is granted for establishing contacts with at least 100 different DXCC countries/entities on the Amateur Radio bands.

My ham radio equipment in 2015
My ham radio equipment in 2015

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Contacts between radio amateurs are usually confirmed by exchanging so-called QSL cards proofing that a particular contact has been made. QSL is an abbreviated radio code which means confirmation. Have a look at a few samples out of the thousands of QSL cards that I've collected throughout the years:

View some samples from my QSL Collection

Making radio contacts however is just one of the many aspects of Ham Radio. A great number of Radio Amateurs prefer to build their own equipment rather than chasing for new countries and use their license to experiment with new and advanced telecommunication techniques. Although many of the older Radio Amateurs will perhaps recall with nostalgia "the good old days" before the existence of computers, new developments in computers, micro circuits and other electronic components offer Amateur Radio a bright new future. Digital techniques play an ever increasing role in Amateur Radio. New stimuli are being given to the development of digital signal processing (DSP), including noise suppression, speech enhancement, filtering and modulation techniques. Those techniques enable radio communicators to perceive the very weak signals that weren't perceptible in those "good old days" of vacuum tubes.

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Radio Amateurs use a great variety of techniques to communicate and experiment with each other including, but not limited to:

Telegraphy (CW);

Logperiodic HF Antenna

Voice or Telephony;


Radio Telex (RTTY/AMTOR)


Packet Radio.

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Switching the transmitter on and off using predetermined sequences is the oldest technique (also used by Marconi more than 100 years ago) to send signals by radio. Using morse code, a unique series of dots and dashes for each character, transmission can reach further distances than speech. For that reason the use of morse code is still very popular under harsh conditions.

Morse Key

Also most of the common terms used in telegraphy contacts between Radio Amateurs are transmitted in an abbreviated form. "Ham" for example is the code for a Radio Amateur, "73" means best wishes while "DX" stands for long distance. Since these codes are used by all Radio Amateurs worldwide, its use doesn't only quicken the speed of communication, it also makes morse code an international "language" allowing contacts all over the world.

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Using a microphone and loudspeaker or headphones linked to a transmitter/receiver is the most common method used by Radio Amateurs to communicate with each other. In fact Radio Amateurs were the first to explore the advantages of single side band techniques to establish telephony contacts, making a more efficient use of the frequency spectrum than the old fashioned double side band techniques.

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Many Radio Amateurs experiment with television transmission techniques. Live television transmissions can be sent and received on a worldwide basis using slow-scan techniques or locally, using the higher frequency bands, in real time.

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These techniques are mostly used for transmitting information bulletins. The bulletins can be received with uncomplicated equipment.

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Another widely accepted way of communication between Radio Amateurs is Packet Radio, a wireless variant of the Internet. This includes sending and receiving E-mail, by radio, exchange of computer programs and distributions of radio bulletins. A world wide radio packet-network is maintained by Radio Amateurs. The peripheral equipment however is more complex then is required for radio telex. The Dutch Packet Network is very active.

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Contrary to the short wave bands, offering global coverage, the practicable communication distances at the higher amateur frequency bands, above 30 MHz, are, because of the earths curvature, limited to approximately 50-100 kilometres under normal or standard propagation conditions. Above average propagation conditions or other natural phenomena, like Meteor Showers, Aurora or Sporadic E-layer reflection, might increase the range of communication on these higher frequencies occasionally up to thousands of kilometres. Although a challenge for the real DX-hunter, these occasional propagation phenomena are not suitable for day-to-day use. In their endeavour to explore and where possible to extend the bounds of possibilities, Radio Amateurs have developed and use various methods to enable medium to long range communication using the higher frequency bands. Among these methods are:

Terrestrial Repeaters;


Satellite Communication


Moon Bounce.

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In its most simple form, a repeater is a one-channel transmitter retransmitting all the signals received by a receiver connected to it. Usually these repeaters are installed on high locations, such as mountains, high buildings or telecommunication towers. In many countries with a dense amateur population (like The Netherlands) a great number of repeaters are operating in the most popular VHF and UHF bands, offering Radio Amateurs with hand portable and mobile equipment extended coverage mainly limited by the height of the repeater antennae.

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Since the achievable communication range is limited by antenna height and the earths curvature, the next logical step is to install such a repeater at an even higher location: in space onboard an artificial satellite orbiting the earth.


The feasibility of this was demonstrated on the 4th of October 1957, when the Soviet Union successfully launched Sputnik I. The world's first artificial satellite was about the size of a basketball, weighed only 183 pounds, and took about 98 minutes to orbit the Earth on its elliptical path. That launch ushered in new political, military, technological, and scientific developments. While the Sputnik launch was a single event, it marked the start of the space age.

Right from the beginning, the Amateur Radio society kept up with the developments in space technology, initially only passively by monitoring the radio signals of the first spacecrafts brought into orbit, soon followed by taking an active part in designing and building satellites for use by Radio Amateurs. The radio beacon of Sputnik-1 was monitored by thousands of radio enthusiasts around the world.

Listen to a historical recording of the Sputnik-1 beacon on 20.007 MHz made by Roy Welch, W0SL (at that time W5SLL) on the 7th of October, 1956.

The first amateur satellite, OSCAR-1 was launched December 12, 1961 by a Thor Agena B launcher as piggyback with Discover 36, a USAF satellite. OSCAR-1 was the first of the phase I satellites. A group of Californian enthusiasts formed Project OSCAR (Orbiting Satellite Carrying Amateur Radio) and persuaded the United States Air Force to replace ballast on the Agena upper stage with the 4.5 kg OSCAR-1 package. The 140 mW transmitter on board discharged its batteries after three weeks. 570 Amateurs in 28 countries reported receiving its simple "HI-HI" morse code signals on the VHF 2 meter band (144.983 MHz) until January 1, 1962. Listen to the OSCAR-1 beacon as recorded by W0SL on the 14th of December, 1961 The speed of the HI-HI message was controlled by a temperature sensor inside the spacecraft. OSCAR-1 re- entered the atmosphere January 31, 1962 after 312 revolutions.

The launch of OSCAR-1 marked the beginning of a new era for the Radio Amateur society with many more satellites to follow. OSCAR-3, launched in 1965, was the first true amateur satellite relaying voice contacts of more than 1000 amateurs in 22 countries in the VHF 2-meter band through a linear transponder, powered by solar energy. OSCAR-3's transponder lasted 18 days. The two beacon transmitters continued operating for several months.

A much longer life cycle became reality with the AMSAT-OSCAR-6 and 7 satellites, launched respectively in 1972 and 1974. Amsat-Oscar-6 lasted 4.5 years and ceased operation on June 21, 1977 because of a battery failure, while Amsat-Oscar-7 was operational for 6.5 years until a battery failure caused its shutdown mid 1981. Both satellites have been used extensively by thousands of Hams around the world, including myself.

Listen to a two-way telegraphy contact I made in 1973 via the A-O-6 with Bulgarian ham operator LZ2FA. Note the manual frequency corrections needed during the QSO to compensate for the doppler shift. Have a look at my equipment used for making contacts via these early generation of Radio Amateur Communication Satellites.

Preparing the Amsat-Oscar-7 for a test in a
thermal vacuum chamber (1973).

In addition to the relay function, the presence of two amateur satellites in orbit at the same time made it possible to demonstrate the possibilities of satellite-to-satellite relay communication as well as low-budget medical data relay and doppler location of ground transmitters for search-and-rescue operations. Both satellites were build by a multi- national (German, Canadian, United States, and Australian) team of Radio Amateurs under the direction of AMSAT-NA.

Amateur Satellite Fuji-Amsat-29 (JAS-2)

The international participation in de development of Amateur Satellite Communication is also demonstrated by this picture showing the Japanese FUJI-OSCAR-29 or JAS-2 (Japanese Amateur Satellite 2), launched on the 17th of August 1996 from the Tanegashima Space Center of NASDA in Japan.

Listen to the digital voice identification (DigiTalker) of the JAS-2 operating in the 450 MHz band, recorded by KB5MU on the 1st of March, 1999.

For a more detailed information related to history and future of Amateur Radio Satellite Communication as well as an over view of the satellites currently in orbit, please refer to the web site of the Amateur Satellite Corporation (AMSAT).

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Another form of long distance space communication used by Radio Amateurs is Moonbounce or EME (Earth-Moon-Earth) whereby the surface of the moon acts as a passive reflector. However initially huge antenna systems, very sensitive receiving equipment and high transmitting powers were required because of the long round trip distance between earth and moon and the very small percentage of the energy reflected back to earth. During two weekends in July 1965 Puerto Rican Ham KP4BPZ made history by using the 1000 foot diameter radio telescope dish in Arecibo connected to his 500 watt 430 MHz transmitter.

Arecibo Radio Telescope, Puerto Rico

Thanks to this huge antenna system in Puerto Rico, KP4BPZ's signals could be received by Radio Amateurs with more modest equipment. Listen to a recording made by W0SL on July 3rd, 1965. The receiving setup used by W0SL consisted of 32-element collinear antenna array and a receiver with nuvistor front end. That time the nuvistor was the latest development in vacuum tube technology but with characteristics not worth mentioning in view of today's technology, which makes EME communication possible with antenna systems much smaller than the one used in Arecibo, thanks to digital signal processing and low noise signal amplifiers.

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More information related to Amateur Radio and links to national amateur radio organizations can be obtained from the website of the International Amateur Radio Union (IARU).

CQ de PA0WLB in morse code

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