Comet SBB-1NMO Compact Dual-Band Mobile vs HYS 21-inch NMO Kit with L-Bracket

The HYS 21-inch wins. Both antennas claim the same gain figure, but their electrical lengths tell the real story. On VHF, the HYS reaches a quarter wavelength (2.2 dBi realistic gain) while the Comet stays electrically short at just 0.20 wavelengths (0.7 dBi). The UHF performance is comparable between them, but VHF is where the HYS pulls ahead. The single most important differentiator is VHF performance: the HYS delivers usable gain on that band while the Comet is compromised.

The Comet suits operators who need maximum compactness and don't use VHF heavily, or who work primarily in UHF-dominant regions. The HYS is the choice for anyone running both bands with an expectation of reasonable performance on each.

Buy the HYS. It costs less, delivers better VHF electrical length, matches the Comet's UHF performance, and owners report the same satisfaction across a much larger sample. The 7-point score difference reflects this: better specs at a lower price.