Abstract
The hobby of amateur radio, or “ham radio” as it is commonly known among its 3 million global practitioners, has been
at the vanguard of electrical and computer engineering since a
young Italian inventor, Guglielmo Marconi, first demonstrated
wireless at his summer home in Bologna in 1894. Ever since
that fateful discovery, amateur radio has played vast and vital
roles in capturing the imagination of inventors, spawning new
technologies, fueling the global engineering work force, and fostering friendship and international goodwill. This three-part series
of articles chronicles the historical evolution of amateur radio,
and shows the astounding impact that the ham radio hobby has
made on both the engineering profession and the world.
Introduction
Since the beginning of the 20th century, the hobby of amateur
radio (or “ham radio” as it is affectionately known) has incubated a global arsenal of trained technical experts, and has served
as the world’s proving ground for wireless communications technologies. The hobby has also provided a unique social melting
pot for people from all walks of life — from ages 5 to 109 — to
share in the passion of wireless communications and experimentation [1, 2]. The avocation of ham radio allows one to tinker
with communication systems, software, electronics, and antennas, facilitating a very strong intuitive understanding of fundamental principles of science, technology, engineering, and math
(STEM). At the same time, practitioners of ham radio develop
social skills and self-confidence by sharing and learning their
craft with others, and gain access to a global network of friends,
colleagues, and mentors through their pursuits of the hobby.
Using tiny slivers of licensed radio frequency bands throughout the entire electromagnetic spectrum, amateur radio operators around the world are granted access to the airwaves through
the Radio Regulations of the International Telecommunication
Union — Radiocommunication Standardization Sector (ITU-R) [3].
Ham operators are licensed by their own country’s government,
assigned a unique call sign identifier for communicating throughout the world, and are permitted to operate their own hobby radio
stations for the purposes of two-way communications, experimentation, and enjoyment. More than a dozen shared ham bands are
available and harmonized across the globe, from the lowest carrier
frequency of 136 kHz (the 2200 meter band, with a 1 W power
limit) to the highest band of 47 GHz in the millimeter-wave regime.
The term “ham” is believed to have originated from wireline
telegraph operators who used the word to denigrate other operators who did not receive Morse code accurately, or who had poor
or unintelligible sending styles (e.g., bad fists). In G.M. Dodge’s
1903 book, The Telegraph Instructor, a “ham” is described as a
poor operator, a “plug.” It seems that early professional wireless
operators brought that pejorative from their wireline practice to
describe the non-paid hobbyists who were building their own
radio stations and were causing radio interference, but the hobby
embraced the label from the onset.
Hams design, build, or buy a wide range of transmitters, receivers, amplifiers, antennas, audio and radio frequency filters, computer controllers, switching systems, and other gadgets in a constant
quest to improve their stations or to enhance operations for a
particular facet of the hobby that most intrigues them. Using their
personal radio stations, which they call “rigs,” hams engage in
experimentation and discovery, enjoy leisurely conversations with
other hams, try out new modes of digital and analog communications, and pursue personal interests among the many varied
aspects of the hobby, such as long-distance (DX) communications,
contesting, emergency preparedness, moon bounce, satellite communications, model airplane remote control, and county hunting,
just to name a few. Many ham operators have “the gift of gab” and
enjoy the art of “rag chewing,” a good-natured term for describing
an extremely long conversation with other hams over the air.
Each country provides its own licensing structure to allow citizens to gain their amateur radio license, offering different classes
of license that incentivize and reward applicants to attain greater
demonstrated levels of technical knowledge and operating proficiency in exchange for greater access to the amateur radio spectrum. Maximum station transmitter power is limited to about 1
kW, depending on country, the class of license, and particular
frequency band. As part of the ITU spectrum allocation, there
is international agreement that amateur radio frequencies are
provided strictly for hobby use, and must be open for anyone
to intercept and eavesdrop over the air to promote self-policing,
although some modulation and coding methods make eavesdropping more technically difficult. Using ham radio to bypass
commercial communication networks is prohibited [4].
Today, amateur radio uses analog transmissions such as Morse
code (CW), single sideband (SSB), and frequency modulation (FM),
and a wide range of digital modulations such as frequency shift keying (FSK), phase shift keying (PSK), and 8-GFSK (Gaussian FSK) for
radio teletype (RTTY), amateur slow scan television (ATV or SSTV)
and weak signal Joe Taylor (WSJT) applications such as meteor scatter, moon bounce, propagation sounding, or other types of weak
signal work. Morse code is still a very popular communications
mode in ham radio, despite the fact that most countries removed
the code proficiency requirement for licensing decades ago. A
computer communications mode known as FT-8 has become
extremely popular in recent years and is used for DX computer
communications with very modest stations or when propagation is
marginal [5]. Casual over-the-air listening (e.g., tuning of the bands)
quickly reveals that rig styles vary widely, from antique tube radios
to ultra-modern direct conversion software defined radios (SDR)
that hams build from scratch (e.g., home brew), purchase in kit form
and assemble, or purchase from a wide range of international vendors. Hams design and deploy their own antennas for their rigs, and
operate from a wide range of locations. Antennas run the gamut
from simple indoor wire dipoles for apartment dwellers, to whip
antennas on vehicles, to massive towers with rotatable yagi beams
erected on large seaside lots or mountaintops. Some hams operate
radio stations, Allstar Node and repeaters by logging in from anywhere via the Internet.
Private Amateur Radio System
The South Coast Reflector is a private amateur radio system consisting of a large number of Allstar nodes linked together on a Allstar HUB 48752,48347,48678 and 18 repeaters located in and around the Houston Texas.
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