Comet SMA-24J (SMA-Female) vs Nagoya NA-771 (SMA-Female)

The Nagoya NA-771 is the clear winner for most handheld users, despite the Comet SMA-24J's superior VHF performance.

The single most important differentiator is VHF behavior. The SMA-24J operates at a proper quarter-wave on VHF and delivers realistic performance around -0.4 dBi. The NA-771 is electrically short at 0.19 wavelengths, suffering a 0.6 dB penalty at -1.0 dBi. On UHF both antennas perform identically at 2.9 dBi, since both achieve 5/8 wave electrical length. The NA-771's claimed 3 dBi gain is accurate; the SMA-24J overstates its capability at 3.5 dBi when VHF performance is actually worse.

Buy the Comet SMA-24J if you primarily operate on VHF and need every tenth of a decibel. Buy the Nagoya NA-771 if you split time between bands or want the best overall value, since its UHF performance matches the Comet while costing nine dollars less, and its overall engineering score is meaningfully higher.

The NA-771 deserves the recommendation for most operators. It's cheaper, better engineered as a compromise antenna, and delivers honest performance claims. Reserve the SMA-24J only for dedicated VHF repeater users.