Definition
The low and medium frequency band, expressed in kilohertz, used by compass locators and non-directional beacons (NDBs) for navigation. Compass locators associated with an ILS transmit on assigned frequencies within this band and are received by the aircraft's automatic direction finder (ADF).
Plain English
A range of low radio frequencies, from 190 to 535 thousand cycles per second, that older navigation beacons broadcast on. Pilots tune these frequencies on the ADF radio to find and follow the beacon.
Context Anchor
Seen in instrument approach material for ILS components, especially when describing compass locators used near marker locations or approach fixes.
Derivation
KHz stands for kilohertz. 'Kilo' is Greek for 'thousand,' and 'hertz' is named after Heinrich Hertz, the physicist who first demonstrated radio waves. So 535 KHz simply means 535,000 radio wave cycles per second.
Why Pilots Care
Identifies the correct frequency band to tune so the compass locator can be received and used as the initial approach fix.
Grounding Statement
This term is simply a range of radio frequencies: the beacon sends, and the aircraft radio listens, within that range.
Intuition Check
Do not read 190—535 KHz as a distance, altitude, or heading. Here it means a range of radio frequencies.
Example Sentence 1
The compass locator at the outer marker transmits in the 190—535 KHz band, so the pilot tuned it on the ADF rather than the VHF nav radio.
Example Sentence 2
Tune the ADF receiver anywhere in the 190—535 KHz range to receive the outer marker compass locator.