2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/125970We propose a covariant protocol for transmitting reference frames encoded on $N$ spins, achieving sensitivity $N^{-2}$ without the need of a pre-established reference frame and without using entanglement between sender and receiver. The protocol exploits the use of equivalent representations, which were overlooked in the previous literature.4 pages, no figures; added new references and improved introduction. Accepted for publication on PRLQuantum Physicstext