How often is DME coded identification transmitted compared to VOR coded identification?

DME (Distance Measuring Equipment) coded identification is transmitted at a different frequency compared to VOR (VHF Omni-directional Range) coded identification. Specifically, the DME identification is broadcasted periodically, typically once every three to four DME transmissions, which helps pilots confirm the DME signal they are receiving is from the expected source.

This practice allows for efficient audio management for pilots, as they are constantly receiving DME distance information, and frequent identification checks would clutter the transmission. Meanwhile, VOR stations transmit their identification with every signal, allowing for constant awareness of the navigational aid being used.

The differentiation in transmission frequency reflects operational practices that aim to provide pilots with the necessary information while optimizing the clarity and availability of communications. This is why the answer indicating a transmission rate of once for every three or four DME transmissions accurately describes the relationship between DME and VOR coded identification transmissions.