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            ROTATABLE CURTAIN ANTENNA FOR SHORTWAVE RADIO BROADCASTING

            GENERAL DESCRIPTION


            The rotatable curtain antenna is a dipole array, consisting of rows and columns of dipoles. The number of rows is usually 2, 4 or 6; the number of columns is usually 2 or 4.

            The rotatable curtain antenna is a high gain directional antenna, designed for medium and long range communications.

            A rotatable curtain antenna usually consists of 2 curtain arrays (one low-band and one high-band) of horizontally polarized dipoles with a reflector screen placed inbetween. The low-band array covers the 6, 7, 9 and 11 MHz bands and the high-band array covers the 11, 13, 15, 17 and 21 MHz bands (or 13-26 MHz bands).

            The number of dipole columns defines the azimuth beamwidth. For a 2-wide dipole array, the beamwidth is around 50°, for a 4-wide dipole array around 30°.

            The number of dipole rows and the height of the lowest element above ground determine the elevation angle and consequently the distance of the service area. A 2-row high array has a typical takeoff angle of 20° and is used for medium range communications, while a 4-row high array has a typical takeoff angle of 10° and is used for long range communications.

            The supporting structure for a rotatable curtain antenna can either be two towers with the antenna suspended inbetween or a single rotating tower with a substructure for the antenna.
            rotatable curtain antenna


            TYPICAL RADIATION PATTERNS
            Azimuth pattern Elevation pattern
            typical azimuth pattern rotatable curtain antenna typical elevation pattern rotatable curtain antenna


            TYPICAL COVERAGE MAP
            typical coverage map rotatable curtain antenna


            TECHNICAL SPECIFICATIONS
            ELECTRICAL
            Azimuth pattern directional
            Frequency ranges 6-26 MHz, up to 6 adjacent SW bands
            Gain 14-24 dBi
            Input impedance 300 ohm balanced
            Polarization horizontal
            Power ratings up to 500 kW carrier with 100% modulation
            Specifications may change without notice

            THIS TYPE OF ANTENNA IS AVAILABLE FROM
            Manufacturer Type number Power Level
            Ampegon Antenna Systems HP-RCA

            H
            Transradio SenderSysteme Berlin A 0686/1

            H
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