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[4] Later, in the mid-1960s, Swan introduced the more full-featured models 350 and 500 transceivers. The Swan 500 was a more costly version of the 350, with higher output power and more operating features. Although they lacked the higher selectivity and tuning accuracy of higher priced transceivers, each performed solidly as a basic SSB station.
The transmitter section provides 1.5 watts of power output on the 144 MHz bands with the supplied FNB-82LI battery pack and 1 watt output on 430 MHz. [ 3 ] The VX-3R is the successor to Yaesu's previous models in the ultra-compact dual-band handheld FM transceiver segment, the VX-1R and the VX-2R .
This article provides a summary description of many of the different antenna types used for radio receiving or transmitting systems. This summary article collects groups of antennas based on their electrical operation. The classification and sub-classifications below follow those typically used in most antenna engineering textbooks. [1] [2] [3 ...
A reconfigurable antenna is an antenna capable of modifying its frequency and radiation properties dynamically, in a controlled and reversible manner. [2] In order to provide a dynamic response, reconfigurable antennas integrate an inner mechanism (such as RF switches, varactors, mechanical actuators or tunable materials) that enable the intentional redistribution of the RF currents over the ...
The J-pole antenna is an end-fed omnidirectional half-wave antenna that is matched to the feedline by a shorted quarter-wave parallel transmission line stub. [5] [1] [6] For a transmitting antenna to operate efficiently, absorbing all the power provided by its feedline, the antenna must be impedance matched to the line; it must have a resistance equal to the feedline's characteristic impedance.
At lower mediumwave frequencies the ground acts mainly as a good conductor, which AM broadcast (0.5–1.7 MHz) antennas depend on. At frequencies between 3–30 MHz, a large portion of the energy from a horizontally polarized antenna reflects off the ground, with almost total reflection at the grazing angles important for ground wave propagation.
2.4 GHz helical antenna radiation pattern (NEC simulation) The Numerical Electromagnetics Code, or NEC, is a popular antenna modeling computer program for wire and surface antennas. It was originally written in FORTRAN during the 1970s by Gerald Burke and Andrew Poggio of the Lawrence Livermore National Laboratory. The code was made publicly ...
Controlled reception pattern antennas (CRPA) are active antennas that are designed to resist radio jamming and spoofing. They are used in navigation applications to resist GPS spoofing attacks. [ 1 ] [ 2 ]