Friday, January 31, 2014

Two wire antennas range of 1.9 MHz

These two simple wire antennas are designed to operate in the 1.9 MHz amateur band . They are connected to a coaxial cable with a characteristic impedance of 50 or 75 ohms. Total length of the wire antenna should be: for the first figure of 38 meters, the second slightly longer than 43 meters . Of both figures show that the wire antenna for 1.9 MHz band as it split into two sections - the antenna itself and reduced to connect the matching device and coaxial cable. Here it should be noted that the ratio of these areas antenna wires can be anything, the main thing here is the total length of the antenna wire and the length of these sections can be arbitrary. Inductance for the first wire antenna is 13 micro Henry , she performed on a frame of 50 mm diameter , has 20 turns of copper wire with a diameter of 0.8-1.0 mm. Winding length of 50 mm. In this design, the wire antenna for 1.9 MHz is much more difficult to make (or find) the variable capacitor ( in terms of its dielectric strength ) , to transmit power to 10 watts , you can use a regular capacitor . Setting a first embodiment of a wire antenna for a range of 1.9 MHz start with the settings in the resonance of the capacitor at the operating frequency , on the selection of the number of coil turns achieve minimum SWR. Antenna in the second picture has an active component of the input resistance of about 50 ohms. Please compensate capacitor C reactive component of the input resistance (it has an inductive character ) , and then pick the length of the antenna SWR , each time adjusting the capacitor C. Because of the high input impedance of this antenna is more efficient than the first wire antenna pattern but the latter is easier to setting , as it requires careful selection of the overall length of the antenna. For these two wire antennas for a range of 1.9 MHz required good " grounding system " , in the simplest case, a system of " earth " should be supplemented by at least one counterweight to the maximum possible length ( but not less than 5 m) .
wire antennas range of 1.9 MHz

wire antennas range of 1.9 MHz

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