Ever since Marconi and Jagadish Chandra Bose transmitted the first radio signals about one hundred years ago, amateur 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 tolerated by the governements and radio amateurs were confined to bands which were considered 'useless' for commercial or public use. After World War II, the vast amounts of surplus equipment, which became available, greatly stimulated amateur radio.
Now, new developments in computers, microcircuits and materials
offer amateur radio a bright new future.
One of the most fascinating aspects of amateur radio, is making radio contacts with other radio amateurs all over the world. And sometimes in remote locations.
Very often friendships for life are made between radio amateurs, carrying out experiments with various equipment and modes, and often advanced, communication techniques.
The Shortwave Listeners ( SWL ), may also contact these amateurs by sending them a QSL card, a postcard-size report which confirms the reception of radio contact made by two amateur stations.
A large percentage of the amateurs prefer experimenting with components and circuits. Others use the computer as an entry point to the hobby. A great variety of equipment is used.
Many of the older radio amateurs will perhaps recall with nostalgia 'the good old days' before the existence of computers. Back then the only equipment in a 'radio shack' was a radio receiver, a transmitter, and a keyer.
In many countries, radio amateurs have founded Amateur Societies which provide forums to exchange ideas and also to protect the interests of the Radio Amateur Service. This is , in principle, not very different from the role of learned societies which cater for the interests of electronics professionals.
Furthermore, since many professional electronics engineers and technicians are also radio amateurs, the distinction between 'amateur' and profession can become very much blurred.
Who are Radio Amateurs?:
Those who pass a written exam - no Morse code is required - is issued a license by the FCC. This license is unique, and is issued by the licensing authority, usually a government department.
The callsign is issued by the FCC at the time of granting a licence.
A licence can only be obtained after successfully passing an amateur radio examination, also conducted under the scrutiny of the licencing authority. The licence permits the radio amateur to carry out experiments in communications by radio, subject to a set of conditions which can be quite complex.
What is a ShortWave Listener ( SWL )?:
Many radio amateurs started their hobby listening to shortwave radio. Starting with radio broadcasts from distant countries, they become interested in receiving weak or distorted radio signals on congested frequency bands. A very popular aspect of his hobby is to monitor radio communications on the many frequency bands, allocated by international agreement to amateur radio.
Receiving other kinds of radio transmission, like standard time signals, may sometimes be very interesting. The reception of signals from radio beacons can provide usefull information about the propagation of radio waves.
The SWL individual very often builds his own equipment, from antennas to receivers and signal processors. And with the availability of personal computers, other communication modes, such as weathermaps, radio telex bulletins, slowscan television and PSK31 have become increasingly popular.
Callsigns:
Radio communication - including communications by radio amateurs - is regulated on an international level by the International Telecommunication Union, ITU, a United Nations body. This organization has assigned to each country in the world a unique code to identify the radio stations which it administers. The code consistes of a short number of characters.
Each amateur radio station is assigned a station identifier - the callsign -which is unique for the entire world.
The call sign consists of two or three parts. For instance: The callsign W9PVR is composed of a prefix (W), a number (9) representing the call area in the U.S. in which the radio station is located, and the suffix (PVR). In the case of W9PVR, the call is a "vanity" call especially requested by the Pine Valley Repeater Amateur Radio Club. So:
A prefix, denoting the administration which issued the licence. This is often the country of residence. It may also indicate the type of amateur station, club station, network, etc. The prefix usually comprises one or maximum two symbols of a combination of letters and numbers. The ITU maintains a large list stating the countries and their callsigns, a list that is regularly updated due to the changing political situation. By convention a number follows the prefix to indicate that the callsign belongs to an amateur station.
The suffix is group of one to three letters, identifying the amateur radio station uniquely.
Another suffix to the callsign may be used to indicate a special situation, such as
/M indicates a mobile station installed in a vehicle.
/A indicates a radiostation operating from a temporary location.
/P indicates that the radio equipment is being used as portable equipment.
Sometimes it is possible for an amateur to operate his station on the territory of a country other than the one which initially issued his permanent licence. In these cases his permanent call may be preceeded by the prefix of the prefix of the host country.
Identifying Shortwave listeners:
In some countries short wave listeners are also issued with an identifying code. The identification is assigned by the association with which they are affiliated.
In the Netherlands, for instance, the issuing government body distributes NL-numbers. In Belgium distributes ONL-numbers and the GOS-listeners (from the former Soviet -Union) are identified by U-numbers. So, you may be confronted with 'NL8800', 'ONL2820' or 'UA3-170-112', indicating SWL's from Holland, Belgium and GOS respectively.
Radio Communication Techniques and Methods:
Telegraphy ( Morse code ):
Switching the transmitter on and off using preditermined sequences is the oldest technique to send signals by radio. Morse is still very popular under harsh conditions. It is a fact that CW signals will be heard when other modes cannot. An appreciation of this communication mode is the fact that many amateurs are learning Morse code despite it no longer being required to upgrade to a higher license.
Telephony:
The transmitter is used to transmit speech, such as is used for almost all radio broadcasts.
PSK31:
What is PSK31 you may ask? It's simple, and yet it's not.
Translated literally, it's an acronym for "Phase Shift Keying, 31 Baud". PSK31 is a form of modulation (or "mode") that offers a new and higher level of performance in conversational communications (keyboard-to-keyboard) that we "hams" (amateur radio operators) can enjoy. And it's been made instantly usable by all of us, due in part to the proliferation of the personal computer, and in part to the superb and generous efforts of some very talented ham/programmers.
Amateur television ( ATV and Slow Scan TV ):
Pictures can be transmitted using a variety of techniques
Mobile and portable use:
Attention is paid to weight and size of the equipment, power consumption. In most populated area's many unmanned repeaters are operated, placed in a high location with good coverage to support communications between mobile stations which could otherwise not contact each other.
Long distance communications ( DX ):
Knowledge of propagation aspects, forecasts and operationg experience are important ingredients for successfull radio commmunications over long distances.
Expeditions to remote locations:
In their endeavour to provide radiocommuncation with all parts of the world, radio amateurs organize to communicate to remote and exotic places. In addition to highly reliable equipment, these expeditions require creativity and well developed organizing talent.
Moon Reflections ( EME ):
Bouncing radio signals is presently the ultimate in radio communication technology. The gap between two amateur stations is bridged by bouncing radio signals off the moon. This activity requires a high level of technical skill and dedication.
Amateur satellites:
The first amateur satellite was launched in 1961. Now, the latest generation of satellites designed and build by radio amateurs provide earth-to-space links. Also on most missions of the MIR space station one of the crewmembers is a licenced amateur radio operator.
Meteor Scatter:
Long distance contacts can be made by reflecting radio waves off the ionized trails left by meteors as they travel through the ionosphere.
Radio Telex ( RTTY en AMTOR ):
These techniques are mostly used for transmitting information bulletins. The bulletins can be received with uncomplicated equipment.
Packet Radio:
This involves 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 extra equipment is more complex then is required for radio telex. Using packet radio, the Dutch Packet Network is very active.
Digital techniques:
Digital techniques play an ever increasing role in amateur radio. New stimuli are being given to the development of noise suppression systems, speech enhancement, filtering and modulation techniques, frequentie generation.
The future for Amateur Radio:
With the explosive growth of computers and miniaturised electronic systems, one may ask if there is still a future for amateur radio.
It is also pointed out that commercially available transceivers can outperform the home-made equipment at considerably lower cost. Furthermore congestion in the amateur frequency bands and interference caused by illegal broadcasting stations (often funded by national sources), make it hard for the beginning amateur operator to make radio contacts.
The advent of multi-media computers, low cost microwave transistors, complex integrated circuits and new materials and components, has expanded possible remedies a great deal.
Special digital modulation techniques, such as 'spread spectrum', can be used for point-to-point transmissions. A new domain for people who prefer to replace complex hardware by programming a personal computer.
Small size and low weight of equipment nowadays and the almost unlimited possibilities to travel to any place on earth, should appeal to the young adventurer.
Working at even higher frequencies is a challenge to the technically oriented amateur. Generating stable frequency at microwave frequencies can be very difficult. Commercial interest in these frequencies is usually broadband, whereas amateur radio mostly use narrow bandwidth systems.
New electronic components can be used in sensitive ultra high frequency transceivers, which can be used to bounce radio waves off natural obstructions, such as the moon (EME) or ionized layers in the atmosphere
Space communications, using amateur satellites, should appeal to the amateur with modest skills in communication practice and technology.
It may occur that an amateur payload is sent on an interplanetary mission. This will require the efforts of a great many amateurs. The constructing of a ground station is comparable with that of an EME station and many of these will have to work under remote control, in a manner comparable to that of a radio telescope. This poses a challenge for the computer programmer as well as for the amateur oriented on radio techniques.
The Internet opens up this new field for radio amateurs who enjoy using their multi-media computer. The added value to Amateur radio could be
Distribution of general information, radio bulletins, articles
Training and education.
Publishing club activities.
Remote and 'real-time' operation of equipment for experimental purposes.
