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Doppler Antenna Head

Spinning Low Band Antenna Head
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Spinning DF Antennas
GTMR designs and builds several versions of lightweight DF antennas which support "to-purpose" and to-vehicle" requirements.
These antennas are specifically designed to be immune to variations in downstream components: the specific receivers and post detection
processors selected to optimize the system performance for the operational environment. As shown below, the same receiver and link components
can be coupled to either GTMR's DopplerDF or Spinning DF type antennas.
The GTMR DopplerDF antenna is a 4-element monolithic array with a groundplane footprint of 8" and height of 7.5" using doppler
principles to derive the target signal direction of arrival. This array operates in the range 20MHz-3GHz and is capable, and suitable, for
targets down to 500KHz. GTMR is also involved in the developmental test of a comparable, larger "dual array" using a groundplane
of 12.5" in diameter (expandable up to 24") and upper (large diameter) and lower (small diameter) arrays totalling a combined height
of 28" improving the lower frequency performance. We have also developed and are testing a filter component for the GTMR DopplerDF which
mitigates the multipath and doppler performance issues encountered when mounting the array on propeller aircraft. While designed specifically
for the DopplerDF, the filter unit is compatible with any similar DF suite.
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