Ham (= radio amateur) radio today differs greatly from that of past years, but it still offers a fascinating way to explore electronics. Here’s a look at how it has changed and what it has to offer both old hands and newcomers alike.
By Doug Grant, K1DG
Many of today’s experienced engineers got their start in electronics through amateur, or “ham,” radio. (Many theories exist over the origin of the term “ham radio,” but there is no consensus.) Over the years, however, the demands of these engineers’ work, families, and communities took precedence, and many hams lost interest and let their licenses lapse. Meanwhile, with the rise of personal communications and Internet connectivity in homes, many young engineers never needed ham radio as a way to explore electronics. They’ve missed the opportunity that this fascinating hobby presents.
The first wireless communicators were by definition all amateurs. Guglielmo Marconi himself, generally regarded as the inventor of radio, once famously remarked that he considered himself an amateur. In the early days of radio, commercial, government, and amateur stations shared the same spectrum, sending broadband spark-generated transmissions modulated by on/off keying using Morse code to convey messages. This practice resulted in a horrendous amount of interference among services until the government stepped in and assigned various services to specific bands.
Government and commercial stations were assigned the supposedly more useful, less-than-1500-kHz, long- and medium-wave spectrum, and the amateurs were banished to the less-than-200m wavelengths with frequencies higher than 1500 kHz. The experts of the day regarded these bands as worthless for long-distance communications.
The amateurs soon discovered that long-distance communications were actually easier at these frequencies. New allocations were then created to give government and commercial stations some of the “good” spectrum. However, a handful of slices of the spectrum were reserved for the amateurs. In the late 1960s, amateurs laid claim to all of the apparently useless frequencies higher than 30 GHz. Since then, as technology has marched on, other services have discovered that these frequencies are useful; amateurs currently enjoy exclusive rights to the frequencies greater than 300 GHz.
In the United States, Part 97 of Title 47 of the Code of Federal Regulations controls the amateur-radio service (Reference 1). It expresses the fundamental purpose of the amateur-radio service in the following principles: recognition and enhancement of the value of the amateur service to the public as a voluntary, noncommercial communication service, particularly with respect to providing emergency communications; continuation and extension of the amateur’s proven ability to contribute to the advancement of the radio art; encouragement and improvement of the amateur service through rules that provide for advancing skills in both the communications and the technical phases of the art; expansion of the reservoir within the amateur-radio service of trained operators, technicians, and electronics experts; and continuation and extension of the amateur’s unique ability to enhance international goodwill.
Licensing
Part 97 requires that amateur stations obtain licenses before they can transmit. The process for getting a ham-radio license has evolved over the years. Long ago, an applicant had to pass a rigorous technical exam that included drawing schematics from memory. The exams have changed considerably. All of the questions are now multiple-choice and cover technical, operating, and regulatory topics, and all of the questions and answers—both right and wrong—are available in the public domain. Furthermore, the governments of many countries—notably, the United States—have effectively outsourced the job of testing.
Read more >> http://www.edn.com/article/519742-Ham_radio_in_the_21st_century.php
EDN (ISSN 0012-7515) is a magazine published by UBM Electronics, a division of United Business Media. Originally called Electrical Design News, the first issue was published by Rogers Corporation in May 1956. With a circulation of over 125,010 in North America alone[2], EDN is also published in Asia, China, Europe, and Japan through partner publishers who license content from UBM Electronics. The magazine is published 24 times per year. It caters to the working electrical engineer and covers new technologies and electronic component products at an engineering level. Columns managing engineers and engineering projects, technical issues faced in the design of electronic components and developing technologies. The editor-in-chief is Patrick Mannion with the editorial offices of the magazine in San Francisco, California and Manhasset, New York, USA. Former owner Reed Business Information sold the magazine to Canon Communications in February 2010, in October of 2010 Cannon Communications was acquired by United Business Media. The "Reality Check" column runs in each issue and takes a look back at a recent technology innovation and the promises it made, comparing the hype to the state of the technology today. The "Design Ideas" department features several reader-submitted designs that are innovative or novel solutions to constrained design problems. Every other issue features a column called "Prying Eyes" which disassembles a popular consumer product and investigates the technologies that enable it.
