Marine, Air, Land Mobile and Fixed Allocations
Designated bands in the shortwave spectrum are used for ships, aircraft, and land vehicles. Shortwave (HF radio) is used by transoceanic aircraft for communications with air-traffic control centers out of VHF radio range. Most countries with HF citizens'-band allocations use 40 or 80 channels between approximately 26.6 MHz and 27.5 MHz, in 10 or 12.5 kHz steps. Part of the 11 m/27 MHz band was also allocated in many countries for early-model cordless phones. Due to antenna-length requirements and the band's long-distance propagation characteristics (undesirable in these cases), much land-mobile radio activity has moved to VHF or UHF and most cordless-phone use is at UHF or higher. Some segments of the HF spectrum are allocated for fixed services, providing point-to-point communication between sites with no access to wired communications.
Read more about this topic: Shortwave Bands
Famous quotes containing the words land, mobile and/or fixed:
“What between the duties expected of one during one’s lifetime, and the duties exacted from one after one’s death, land has ceased to be either a profit or a pleasure. It gives one position, and prevents one from keeping it up. That’s all that can be said about land.”
—Oscar Wilde (1854–1900)
“From three to six months, most babies have settled down enough to be fun but aren’t mobile enough to be getting into trouble. This is the time to pay some attention to your relationship again. Otherwise, you may spend the entire postpartum year thinking you married the wrong person and overlooking the obvious—that parenthood can create rough spots even in the smoothest marriage.”
—Anne Cassidy (20th century)
“Indeed, I thought, slipping the silver into my purse ... what a change of temper a fixed income will bring about. No force in the world can take from me my five hundred pounds. Food, house and clothing are mine for ever. Therefore not merely do effort and labour cease, but also hatred and bitterness. I need not hate any man; he cannot hurt me. I need not flatter any man; he has nothing to give me.”
—Virginia Woolf (1882–1941)