12-09-2017, 11:50 AM
The resource is currently in dxzone.com in 1 categories. The main category is Wire antenans and dipoles, Long Wires which is about Long Wire and Dipole Antenans for Ham Radio. This link appears in our website directory since Sunday, February 28, 2016, and to this day "Basic Cable Antennas Part I" has been followed for a total of 1105 times.
A random wire antenna usually consists of a long cable (at least one quarter wavelength) with one end connected to the radio and the other in the free space, arranged in any way more convenient for the space available. Ideally, it is a straight wire that is as high as possible between trees or buildings, the insulated ends of supports with deformation insulators. Typically it is made of 12 or 14 AWG coated copper wire (1.6 to 2.0 mm (0.063 to 0.079 in) diameter). Folding the wire in a zigzag pattern to fit in a limited space like an apartment or attic will reduce efficiency and make theoretical analysis extremely difficult. (The added length helps more than what folding usually does.)
If used for transmission, a random wire antenna will usually also require an antenna tuner, since it has an unpredictable impedance that varies with frequency. One side of the tuner output connects directly to the antenna, without a transmission line, and the other to a good ground. A quarter-wavelength-long cable works best, and unless it is fed through unun, a medium-wavelength will exceed the matching capacity of most tuners. Even without a good ground, the antenna will also radiate, but will do so by coupling capacitively to any near conductive material; however this is not recommended. The terrain for a random wire antenna can be chosen by experimentation. The grounds could be returned to a nearby cold water pipe or a wire of approximately a quarter wavelength, or may be replaced by randomly disposed fourth wave wavelength wires attached to the ground.
A random wire antenna usually consists of a long cable (at least one quarter wavelength) with one end connected to the radio and the other in the free space, arranged in any way more convenient for the space available. Ideally, it is a straight wire that is as high as possible between trees or buildings, the insulated ends of supports with deformation insulators. Typically it is made of 12 or 14 AWG coated copper wire (1.6 to 2.0 mm (0.063 to 0.079 in) diameter). Folding the wire in a zigzag pattern to fit in a limited space like an apartment or attic will reduce efficiency and make theoretical analysis extremely difficult. (The added length helps more than what folding usually does.)
If used for transmission, a random wire antenna will usually also require an antenna tuner, since it has an unpredictable impedance that varies with frequency. One side of the tuner output connects directly to the antenna, without a transmission line, and the other to a good ground. A quarter-wavelength-long cable works best, and unless it is fed through unun, a medium-wavelength will exceed the matching capacity of most tuners. Even without a good ground, the antenna will also radiate, but will do so by coupling capacitively to any near conductive material; however this is not recommended. The terrain for a random wire antenna can be chosen by experimentation. The grounds could be returned to a nearby cold water pipe or a wire of approximately a quarter wavelength, or may be replaced by randomly disposed fourth wave wavelength wires attached to the ground.