Open-source phased-array radar project claims ~20 km range for ~$5k

The post highlights an open-source DIY radar with a phased-array (AESA/PAR-like) design reportedly built from off-the-shelf parts for about $5,000 and claiming up to ~20 km range. Novelty is the low-cost, reproducible open design that could, in principle, enable grassroots production of battlefield-relevant surveillance sensors, though the author argues scaling to industrial quantities would erase much of the cost advantage.