Retevis RHD-771 (SMA-Female) vs TIDRADIO TD-771 GMRS (SMA-Female)

The TIDRADIO TD-771 GMRS is the better antenna for its intended purpose, though the choice depends entirely on your radio's operating band.

The critical difference is electrical length. The RHD-771 performs as a compromise antenna across dual bands: it's electrically short on VHF (0.19 wavelengths, delivering realistic -1.0 dBi), which significantly underperforms on 2-meter voice. On UHF it reaches 5/8 wave and becomes respectable at 2.9 dBi. The TD-771, built specifically for GMRS, achieves 5/8 wave electrical length at 465 MHz, yielding a realistic 3.0 dBi gain. Both claim 2.15 dBi, but the RHD-771's claim is optimistic given its VHF shortfall.

The single most important differentiator is band optimization. The RHD-771 attempts to serve both VHF and UHF equally and fails at VHF. The TD-771 commits fully to GMRS performance.

Buy the RHD-771 if you operate primarily on UHF or need occasional VHF coverage from a dual-band radio and accept VHF compromises. Buy the TD-771 if GMRS is your focus, where it delivers superior electrical efficiency.

For most handheld users, the TD-771 is the smarter choice due to its band-specific design and reliable 5/8 wave performance.