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:
“The windy springs and the blazing summers, one after another, had enriched and mellowed that flat tableland; all the human effort that had gone into it was coming back in long, sweeping lines of fertility. The changes seemed beautiful and harmonious to me; it was like watching the growth of a great man or of a great idea. I recognized every tree and sandbank and rugged draw. I found that I remembered the conformation of the land as one remembers the modelling of human faces.”
—Willa Cather (1873–1947)
“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)
“It is not merely the likeness which is precious ... but the association and the sense of nearness involved in the thing ... the fact of the very shadow of the person lying there fixed forever! It is the very sanctification of portraits I think—and it is not at all monstrous in me to say ... that I would rather have such a memorial of one I dearly loved, than the noblest Artist’s work ever produced.”
—Elizabeth Barrett Browning (1806–1861)