https://www.subseatechnologies.com/hemisphere-gnss/antennas/a31/
A31 Antenna
The A31™ antenna is designed to help maintain tracking of GPS, Beacon and differential correction signals in challenging environments. Sometimes keeping the antenna level and away from electrical noise is just not possible. With improved multi-path mitigation and ability to filter out an additional 30 decibels of radio band frequencies, A31 offers superior noise rejection. The A31 is designed for use with Hemisphere GNSS Crescent and Crescent Vector II receivers.
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