Amateur radio - a fascinating hobby
Table of contents
Ever since Marconi transmitted the first radio signals accross the Atlantic ocean,
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 'usesless' 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 contact 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, and often advanced, communication techniques.
The short wave listener ( 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 experiment with components and circuits.
Others use the computer as an entry point to the hobby.
A great variety of techniques is used.
Many of the older radio amateurs will perhaps recall with nostalgy
'the good old days',
before the existence of computers.
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. 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.
Attached to the licence is a unique callsign, which is issued by
the licensing authority, usually a government department.
The callsign is issued 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.
Many radio amateurs started their hobby listing 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 internation 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 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 have become increasingly popular.
Radio communication - including communications by radio
amateurs - is regulated on an international level by the International Telecommunication
Union, ITU, a United Nations body. This organisation 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:
- 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.
s of a combination of letters and numbers.
The ITU maintains a large list stating the countries and their
prefix codes,
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.
- A 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.
- 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 the VERON
distributes NL-numbers and the
VRZA
distributes PA-numbers.
In Belgium the UBA 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.
- 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.
An appreceation of the communication mode is given in
Ode to DAH Code
- Telephony
-
The transmitter is used to transmit speech, such as is used for almost
all radio broadcasts.
- 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
expeditions
to remote and exotic places. In addition to highly reliable
equipment, these expeditions require creativity and well
developed organizing talent.
- Moon Reflections ( EME )
-
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.
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 miniturised
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 computers.
- Small size and low weight of equipment nowadays and the allmost unlimited
possibilities to travel to any place on earth, should appeal to the young
adventurer.
- Working at ever higher frequencies is a challenge to the
technically oriented amateur.
Generating stable frequecies at microwave frequencies can be very difficult.
Commercial interest in these frequencies is usually broadband, whereas amateur radio
mostly employe 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 athmosphere.
- 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 enyoy 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 experimantal purposes.
Miscellaneous
Further information on amateur radio
Interesting publications in relation to Amateur radio.
Links to information on equipment manufacturers, magazines on amateur radio, related
subjects like amateur astronomy, space research, can be found at
the Home Page for
Amateur Radio
In order to improve our service to the amateur radio community, we welcome
your remarks and suggestions
about this page.
Pieter J.T.Bruinsma (PA0PHB)
PACKET radio address: PA0PHB@PI8WNO.UTR.EU
Updated on 970210.