PBO conclusion

When we started this test, I thought it would be a straight head-to-head between the Furuno and Quantum units. As it turned out, they might employ similar technology, but are very different products. Furuno have thrown their effort into trying to produce open-array range and resolution in a smaller package, while Raymarine have exploited pulse compression to offer shortrange resolution hitherto only possible with FMCW radar.

Furuno’s claim that the DRS4D-NXT ‘packs the performance of an open-array radar in a compact 24in radome’ is not strictly true, but it does a pretty good job of it at medium range. The naturally narrower beam width from the larger scanner gives better target separation than the Quantum; this is improved further by the RezBoost processing, which in many situations simulates a narrower beam width well but does come with a risk, as shown by our tests at Hythe Pier and in the Hamble Channel. Here, RezBoost was observed to separate long targets or side lobe smears into multiple returns on screen, which could be misleading.

At close range, the Quantum clearly wins on separating targets on the same bearing at similar ranges, something which neither the Furuno nor the open-array can achieve, and handles side lobe issues better than the Furuno, giving a clearer picture of large, flat objects at close range.

In practice, these differences