How often is the DME ID signal transmitted relative to the VOR/LOC ID?

• A. Once every three or four times the VOR/LOC ID is heard
• B. Every second
• C. Always continuous
• D. Only during arc

Answer: (A)

The key idea is that DME identifications are not transmitted continuously; they appear intermittently, tied to the VOR/LOC ident transmissions. In a paired VOR/DME installation, the DME ID is broadcast in a fixed pattern: it is sent once for every three or four times the VOR/LOC ident is heard. This keeps the identification clear and helps you confirm that the DME is associated with the VOR/LOC you’re using. So after hearing several VOR/LOC ident repeats, you’ll get the DME ident, indicating the DME is up and linked to that VOR/LOC. Continuous or every-second transmission wouldn’t reflect how the equipment schedules ident signals, and being active only during an arc isn’t how the standard schedule works.