Five simple antennas.
This is a folded dipole that uses 300 Ohm TV twin feed-line throughout. The length L is calculated using standard dipole formulas(468/Frequency in Mhz, for feet, or 143/Frequency in Mhz for meters) with a loss factor of about 2-5% factored in. Two shorting straps are soldered close to the ends at 0.07L, a distance of 0.86L apart. The two wires at the ends of the feed-line are then soldered together to make a folded dipole. Folding a dipole makes it broad-banded around the design frequency. The design frequency should be the center of the band where you want to operate or listen. At a distance M from the feed-point of the feed-line a Silvered Mica capacitor is soldered across the feed-line. The result is a 50 Ohm balanced antenna. To feed an unbalanced system, a 1:1 Balun or Balanced antenna matching unit should be used. The antenna can be positioned between two trees or poles for horizontal polarization, and for omni-directional performance vertically, as an inverted L or V. Note that this antenna should be used only for power outputs less than 150W.
The G5RV when used with an appropriate antenna matching unit exhibits broadband characteristics with effective radiation patterns on all HF bands. This illustration shows the half size G5RV, which can be used on all bands from 40M to 10M. The dipole legs are copper wire, bare or insulated cut to 51.3 feet. The matching section is 300, or 450 Ohm twin feed-line, cut to 17 feet. Coax cable(RG-58) is used to feed the matching section. At the feed-point to the matching section, a 1:1 Balun may be used between the coax, and twin feed-line. The coax feed-line can be any length. In place of the Balun, a coax choke can be made by winding 8-10 turns on a plastic form 3-6 inches in diameter. The G5RV can be positioned as a inverted V, or L, but the matching section should drop vertically
This type of antenna exhibits an omni-directional pattern, with a low radiation angle. The length of the radiator is calculated by using the formula 234/Frequency in Mhz, for feet, or 71.5/Frequency in Mhz, for meters to make a 1/4 wavelength, at the desired frequency. The radiator can be made entirely from 1" aluminum tubing, but can also be made from several sections of tubing of different sizes (Below 20M it is not appropriate to use 1" tubing). These could be fastened together using pipe clamps, after splitting the lower section about 1", across the circumference, along the diameter to facilitate clamping of the upper section. The radiator is mounted on a reasonable length square wooden post which is buried in the ground or fastened to the roof. Large diameter pipe clamps are used to fasten the radiator to the wooden pole. At about 1/2" from the base of the radiator a hole 1/8" should be drilled into the aluminum pipe. This hole is used for a bolt onto which the coax center conductor is fastened. The radials should be slightly longer than the radiator. To facilitate multi-band operation at least four radials should be used for each band you wish to operate in, the radiator being cut for the lowest band. All the radials are then fastened, or soldered together, and a connection is made to the coax cable shield. The radials should be buried a few inches into the ground, and ideally spread out in a circle. An antenna matching unit is used for multi-band operation. Alternatively, in place of aluminum tubing, a PVC pipe could be used, with a 1/4 wavelength wire positioned inside as the radiator. Note: For this antenna the Antenna Matching Unit should be at the base of the antenna, for best performance, and can be remotely controlled.
A simple, but effective antenna can be constructed from copper insulated wire to extend the range of hand-held radios. Cut a wire to make a 1/2 wavelength dipole, using the formulas in Fig. E. Remove excess wire with a factor of 0.02-0.05. Then cut the wire at the exact center. Solder the center connector of a coax cable to one piece, and the coax shield to the second piece. Tape, using insulating tape/duct tape to a window in the direction you want to communicate as shown, and you have built yourself a range extending single band VHF/UHF antenna. Design the antenna around the center of the VHF/UHF band you want to operate in.