Sunday, July 11, 2010

Microwaves And The Amateur Satellite Program

The OSCAR satellite program utilizes several amateur microwave bands, and future projections call for yet more use of these bands . OSCAR8, for example, produced a mode-] output on 70 em that could easily be received by basic amateur setups. The OSCAR 9 satellite includes beacon transmitters operating in the 13-cm and 3-cm bands, which again reflects the wave of future events. OSCAR Phase III satellites are projected to afford communication capabilities in the 23-cm, 13-cm, and 3-cm bands, thus our amateur microwave spectrum may become quite popular and commonplace during the mid 1980s. See Fig. 1-7.

Fig. 1-7. OSCAR 8, a Phase-II Amateur Radio satellite, orbits approximately 800 miles above the Earth, where it relays 7D-cm,2-meter, and to-meter signals. Future (Phase-III) spacecraft will use 432, 1260, and 10,000 MHz to provide hemisphere-wide communications capability.

The microwave spectrum, with its reliable line-of-sight propagation, is particularly appealing for future geostationary (Phase III) OSCAR satellites. Relatively large dish antennas can be directed at these satellites, resulting in very dependable communications. Through the use of earth-based microwave OSCAR links, one or two spacecraft may be interlinked for near global communications. Future OSCAR satellites are destined to be recognized as prime users of amateur microwave frequency allocations.

The microwave spectrum in its entirety promises to be a major factor in future amateur-radio pioneering. The vast bandwidth allocations, combined with computer communications and other advanced technology forms, will permit this range to be used in a heretofore unrealized manner. Dependable and reliable amateur communications with distant lands will be provided by long range OSCAR satellites, while cross-country microwave networks will provide nationwide signal linking.

Hand-help FM transceivers will also gain "seven-league boots" through microwave links and FM-to-SSB converters situated at OSCARsatellite uplink points. Also, EME systems may use moonbased microwave repeaters. Amateur pioneering efforts, however, will not cease ; a creditable rise of interest in radio astronomy will serve as proof of that situation.

The following chapters of this book describe, in easy-tounderstand form, the exciting world of amateur microwave operations. Separate discussions of the history of microwaves, getting started in microwaves, and detailed information on equipment and operations on various bands is included. This works is thus a guide for microwave newcomers. Here's your invitation and join the excitement of this challenging amateur frontier. Come on along and get in on the action! See Fig. 1-8.

Fig. 1-8. A view of the future of Amateur Radio communications? A 10-GHz Gunnplexer and 2-meter hand-held transceivers combine to expand the horizons.