DHAMO: Digital HF Antenna - Vertical Monopole

Main application of the digital vertical HF monopole is long-range skywave reception, for use in arrays.

DHAMO Digital HF short monopole in its natural environment (prototype)

DHAMO Digital HF short monopole synoptic

This fully-integrated 2-30 MHz receive antenna includes integrated synchronous channelizing receiver and auto-calibration. Synchronization is achieved through FEE's "SyncNet" picosecond synchronization system. Two GPS antenna (below radome) allow automatic relative positioning in the centimetric range when used in array, easing installation procedure (computing is done by the array controller remote computer from all antennas' preprocessed GNSS data). DHADI digital horizontal double dipoles or SYDRE digital receivers connected to third-party antennas can be merged in the array, allowing for example polarization diversity.
The picture shows a prototype antenna, its height is about 2.5 meters. The HF signal is channelized and equalized, the time-stamped output data is sent through ethernet multicast. In nominal configuration, channelization provides 3535 consecutive channels of 8 kHz bandwidth complex signals (28.28 MHz total bandwidth), each sampled at 10 kHz. If required, an efficient user-level FFT-based computing stage allows higher bandwidth signal reconstruction.
At least 2 optical fibers are required for use in an array configuration (SyncNet & 10G ethernet), 2 more fibers can be used for redundancy. A minimal 48VDC and maximal 60VDC (for line losses account) power supply is required. Of course, the antenna can be used alone, without SyncNet (internal OCXO's timebase used then).
Power consumption is temperature-dependant, typically 60-70W.