HOME     STORE     BLOG     SCHEMATICS     TUTORIALS     DOWNLOADS     CONTACT

A modified version of the simple dipole is the folded dipole. It has two half-wave conductors joined at the ends and one conductor is split at the half-way point where the feeder is attached. If the conductor diameters are the same, the feedpoint impedance of the folded dipole will be four times that of a standard dipole, i.e. 300 ohm. The height above the ground The height of an antenna above the ground, and the nature of the ground itself, has a considerable effect on the performance of an antenna.and its angle of radiation. See PROPAGATION A dipole antenna can be arranged to operate on several bands using other methods. One way is to install "traps" in each leg.

This Antenna is most widely used all over the world. For example, when you see a police car it has a transmitter with Ground Pole Antenna The body of car serves as ground). It accepts load from 50 ohm source and has larger power output than Half-Wave Dipole Antenna.

It accepts load from 75 ohm source and has much smaller power output than Ground Pole Antenna. Use this antenna only when you don't have GP Antenna. Construction: Two aluminum rods ,each of length "L" in meters are joined together through an insulator as shown in fig. From center, 75 ohm cable is feeded just like ordinary TV antenna.

Tuned for 89MHz in the FM broadcast band.

This simple 7 element Yagi is ideal for portable operation. The elements can be removed and replaced in a few minutes. The 2.42 Metre boom will fit inside my car. All of the elements are made from 6mm solid aluminum rod. The boom is made from 50x25mm (2x1 in) timber. The driven element is a half wavelength dipole. Unlike the more common type of folded dipole, this dipole is folded on one side but not on the other. For want of a better name, lets call it a 'half folded dipole'. The co-ax cable braid is connected to the centre of the dipole. The co-ax centre conductor is connected to the folded dipole section (see diagram above).

It is very easy to create a simple 1/2 wave dipole, all you need is some lengths of wire such as the core of some mains flex or even a straightened out metal coat hanger, some co-ax cable and a connector for your scanners antenna input (usually BNC or SMA). Dipole Antenna The formula to calculate the length of the antenna is 147/frequency in MHz, this give the total length of the dipole in centimeters. For example, to make a 150MHz dipole: 147/150 = 98cm so each element of the dipole should be 49cm

Together with a good directional antenna this high performance two-stage antenna amplifier for the VHF FM broadcast band will enable you to receive distant radio stations. VHF FM Antenna booster will also drastically improve reception of FM signals you’ve come to accept as marginal and noisy in your area. Antenna booster is also great for extending transmission range of low power VHF / FM transmitters.

This HD TV UHF wideband amplifier(Ultra High Frequency amplifier) has a total gain of 10 to 15 dB in the 400 – 850 MHz domain frequency so it can be used where the tv signal is weak. For this UHF antenna tv amplifier to work correctly you need to cut the components pins as short as possible. C1, C2, C6, C7 are SMD type ( surface mounted ). This antenna tv amplifier or uhf wideband amplifier need to be build inside of a metal box and then connected close to the tv antenna.

To improve signal transmission or reception in specific directions, basic elements, either vertical or horizontal, can be combined to form arrays. The most common form is the Yagi-Uda parasitic array commonly referred to as a Yagi array or beam. It consists of a driven element which is either a simple or folded dipole and a series of parasitic elements arranged in a plane. The elements are called parasitic because they are not directly driven by the transmitter but rather absorb energy from the radiated element and re-radiate it.