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Broadband shortwave base antennas traditionally fall into two main categories: Resistively loaded antennas which can be inexpensive and reasonably compact but inefficient at lower frequencies. Large elaborate and very expensive, non-loaded designs. (These can cost upward of $80,000 to purchase and install).
Curtain arrays were originally developed during the 1920s and 1930s when there was a lot of experimentation with long distance shortwave broadcasting. The underlying concept was to achieve improvements in gain and/or directionality over the simple dipole antenna, possibly by folding one or more dipoles into a smaller physical space, or to arrange multiple dipoles such that their radiation ...
In the case of an AM broadcasting station (mediumwave and longwave, occasionally shortwave), the multiple mast radiators may all be part of an antenna system for a single station, while for VHF and UHF the site may be under joint management. Alternatively, a single tower with many separate antennas is often called a "candelabra tower". [6]
Ultimately shortwave relays for network programming was determined to be inferior to dedicated telephone line connections, and the transmissions to KFKX ended, with the Hastings operation closing on June 1, 1927. [6] In 1922, a 1 kW shortwave transmitter was installed at Westinghouse's factory in East Pittsburgh, Pennsylvania, with call sign ...
A few examples of areal made of cage sections are: Shortwave quadrant antenna made of two horizontal cage sections. [1]Quadrant antenna A quadrant antenna is an omnidirectional shortwave transmitting antenna shaped like a rhombus or lozenge, made from two identical, opposing L-shaped cage dipoles ("L ⅂") lying in the same horizontal plane, aligned with their 'elbows' pointing in opposite ...
The ALLISS module is a fully rotatable antenna system for high power (typically 500 kW only) shortwave radio broadcasting—it essentially is a self contained shortwave relay station. Most of the world's shortwave relay stations do not use this technology, due to its cost (15m EUR per ALLISS module: Transmitter + Antenna + Automation equipment).
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The 15-meter band (also called the 21-MHz band or 15 meters) is an amateur radio frequency band spanning the shortwave spectrum from 21 to 21.45 MHz. The band is suitable for amateur long-distance communications, and such use is permitted in nearly all countries. [citation needed]