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An ideal “broadband” shortwave antenna would work continuously across much of, if not all of, the shortwave spectrum with good radiation efficiency and minimal compromise of the radiation pattern. Most practical broadband antennas compromise on one of the above: Either they only work on a few relatively narrow slices of the HF radio ...
Tests done by J.S. Belrose (1994) [7] showed that though the conventional T²FD length is close to a full-size 80 meter (3.5–4.0 MHz) antenna, the antenna starts to suffer serious signal loss both on transmit and receive below 10 MHz (30 m), with the 80 meter band signals −10 dB down (90% power loss) from a reference dipole at 10 MHz.
One must assume that only about 10% of HRS type antennas are rotatable, but compiled statistics are fragmentary. Only about 20% of rotatable HRS antennas are ALLISS, but this may be a slight overestimate. The Transmitter Documentation Project has most but not all stats on shortwave relay station antennas in use or historical.
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 ...
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).
Only electrical waves traveling toward the feedpoint are collected; waves traveling away from the feedpoint are grounded through a terminating resistor at the end of the wire opposite the feedpoint. The resistive termination makes the antenna receive in only one direction, similar to an aperture antenna but much simpler to build. In order to ...