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Strategic High Sensitivity HF NVIS DF Element


The DF-A0115 antenna is a single site location (SSL) HF DF array element. Polarisation is selectable between linear vertical, RHCP and LHCP though the injecting of different DC voltages onto the switch board via a dedicated control interface. On the DF-A0115-01 linear vertical, RHCP and LHCP are available as three separate, simultaneous outputs with pre-amplification. The antenna is intended for use in constructing DF interferometer arrays consisting of a number of DFA0115 antennas. It can be deployed as part of either a linear or circular array. The large physical size of the product provides the best possible sensitivity at HF frequencies. The antenna includes an integrated switching system and lightning and ESD protection. There are no nonlinear active components in the chain to introduce unwanted distortion on the received signals. In LHCP and RHCP modes, the antenna element is capable of receiving waves of LHCP and RHCP polarisation respectively, incident from the upper half sphere, with a gain peak at Œ? = 0° (directly upwards). In VP omni mode, the antenna operates similar to a monopole antenna, able to receive waves with vertical polarisation with a gain peak on the horison (or just above it) and a null at Œ? = 0°. Unlike competing products of the same kind, this antenna utilises our patented stabilised loop technology that eliminates cross polarisation disturbance of the antenna, providing enhanced reliability, accuracy and repeatability in practical use. The antenna is designed only for fixed site installation on a plinth or other mechanical support structure. The antenna additionally requires guying for installation.

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Frequency range 1 - 30 MHz
VSWR < 2.0:1 (typical CP modes)
Nominal impedance 50 O
RF power handling Passive
Polarisation Linear
Connector N-type (female)
Power supply DC injected to select polarisation (+5 V VP
Switching cycles Designed for 100 Mc
Total height < 4510 mm
Total diamete < 3000 mm
Dimensions packed < 2450 x 570 x 440 mm
Ground radials 16 x 6m radials
Total mass < 60 kg
Mounting Mounted using plinth and ground radial plate
Colour Primarily black

    Product Applications

    Signals Intelligence
  • Radio Direction Finding
  • C-ESM

    Design Features

  • Passive (no distortion). Integrated switching system. Lightning/ESD protected. Compact stowed form factor. Patented stabilised loop excludes cross polarisation inaccuracies. Incorporated lightning protection. Ground radials and guy ropes provided .