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In the most basic form, a quarter-wavelength section of coaxial cable is prepared such that the inner and outer conductors are separate but still attached to the remaining cable. The outer (shield) conductor is connected to a quarter-wavelength conducting sleeve into which the cable is inserted, and the inner conductor protrudes vertically ...
The HB9XBG antenna is a vertical dipole antenna for short wave radio amateurs. It was developed by the Swiss radio amateur Walter Kägi, whose call sign HB9XBG is also the designation of the antenna. [1] During the test phase in 2020, HB9XBG built two vertical dipoles – one for the 20-metre amateur radio band and another for the 40-metre band.
The G5RV antenna is a dipole antenna fed indirectly, through a carefully chosen length of 300 Ω or 450 Ω twin lead, which acts as an impedance matching network to connect (through a balun) to a standard 50 Ω coaxial transmission line. The sloper antenna is a slanted vertical dipole antenna attached to the top of a single tower. The element ...
The ends of the symmetric feedline can be soldered directly onto a 50 Ω coax cable to the transceiver, [2] however this is not good practice and should be avoided: It can result in high current flow on the outer surface of the coax braid, causing RF interference and degrading the polarization and gain of the antenna.
The balun is a 16:1 ratio, thereby transforming the 50 Ω (ohm) coax to an 800 Ω feed at the antenna. The resistor load is also 800 Ω, non-inductive. This allows the antenna impedance to swing from 400–1,600 Ω over the frequency range intended and thus keep the SWR at the transmitter 2:1 or lower.
Moore describes his antenna as "a pulled-open folded dipole". While the main point of Moore's patent was the two-turn single loop design, which is not the antenna termed "quad" today, the patent does include a mention and illustration of a two-element unidirectional "quad", and describes the time when the full wave loop concept was developed:
He was first employed by the U.S. Air Force and then GT&E Sylvania Electronics Systems on CDAA and other antenna projects. Professor Edgar Hayden, then a young engineer in the University of Illinois Radio Direction Finding Research Group, led the reassembly of the Wullenweber , studied the design and performance of HF/DF arrays and researched ...
Inverted-'V' antenna When the two arms of a dipole are individually straight, but bent towards each other in a 'V' shape, at an angle noticeably less than 180°, the dipole is called a 'V' antenna, and when the dipole arms' end closer to the ground than their center branch-point, the antenna is called an inverted-'V' . The inverted-'V' is ...