09 novembre 2011

EeTimes: i radioamatori del XXI secolo guardano anche al passato

Sulle riviste professionali del circuito EeTimes e Electronics Design News compare un lungo articolo di Doug Grant, K1DG, sul mondo dei radioamatori e dei loro progetti di elettronica. Il bello è che accanto alle apparecchiature di ultima generazione e alto costo, molte delle quali ormai basate su sofisticate tecniche DSP e SDR, ecco citate alcuni progetti per autocostruttori di piccoli dispositivi "QRP", la sigla radioamatoriale che identifica le potenze trasmissive più basse. Tra i vari esempi lo straordinario "DereLicht", un trasmettitore telegrafico da un Watt e mezzo per la banda degli 80 metri realizzato con i componenti rubati a una piccola lampadina a basso consumo (più un quarzo e quattro condensatori aggiuntivi), il progetto open hardware OpenQRP e una sfilza di progetti circuitali per realizzare, sempre con pochissimi componenti, ricevitori "rigenerativi" (riportati sulla pagina di Charles Kitchin, N1TEV) . Il minimalismo, in elettronica, rimane l'approccio più divertente e appagante.
Ham radio in the 21st century

Ham 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.

Doug Grant, K1DG -- EDN, November 3, 2011

The US amateur-licensing process no longer requires knowledge of Morse code—historically, a major impediment for many individuals.
The signal-processing capabilities of a sound-card-equipped PC that connects to an HF single-sideband or a VHF FM transceiver have driven the emergence of new modes.
Most high-performance HF and VHF transceivers now use digital-signal-processing technology for at least some of the modulation, demodulation, and filtering functions.
Ham operators have always been enthusiastic tinkerers, often building their equipment from discarded pieces of consumer electronics they find in their neighborhoods.
Ham radio brings new aspects to other hobbies, such as mountaintop hiking and orienteering.
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.

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