DAMM BS422 Review: Mast Top Base Station Design for Australian Mines
The DAMM BS422 is a software defined outdoor base station that runs up to four carriers of TETRA, DMR Tier III, TEDS or analogue from one 12 kg IP65 box, and it is built to sit at the top of the mast beside the antennas instead of in a shelter at the bottom. Removing the feeder is worth about 6 dB of round trip system gain at 415 MHz on a 50 m run, and the same enclosure works as a base station or as a repeater slave, which is what makes a single network across an open pit and a decline practical without fibre underground. The four carriers are not four full power carriers, though, and the 400 MHz version on DAMM's published ordering list does not fit the Australian band plan. This review works the capability against a surface and underground mine, sizes the carriers and the traffic, quantifies the mast top and receive diversity gains, and sets out the band, duplex, power and compliance decisions that have to be settled before the purchase order goes out.
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