NDB question

is there any good videos on understanding NDBs? I cant seem to understand how to use them

yes I watched navigating infinite flight video and that did not help me at all

Hello! Here’s a video below about what an NDB is and how it works. Hope this is helpful. There isn’t any NDB in app video tutorials I know of.

5 Likes

The signal points towards the station. Allowing you to home in on the station. The direct quote from the AIM:

1−1−2. Nondirectional Radio Beacon (NDB)
a. A low or medium frequency radio beacon transmits nondirectional signals whereby the pilot of an aircraft properly equipped can determine bearings and “home” on the station.

1 Like

ADFs or Automatic Direction Finders have you “home in” on an NDB station, rather than intercept a radial like a VOR.

Suppose you’re flying a magnetic heading of 270 aka due west.

You fire up an NDB frequency on your NAV1. The needle on your ADF (whose compass card usually always points due north in most aircraft) swings around and points to a heading of 150.

What does this mean?

It means that to home in on the NDB, you have to fly a heading of either 270 + 150 (=heading 420) or a heading of 270 - 150 (=heading 120) to home in on the station. Since we know there’s no possible heading of 420, the only option is to turn to a heading of 120, and the ADF needle will point directly ahead. You’re now homing in towards the station.

Note: some aircraft have ADFs with moveable/rotatable compass cards. In that case, you simply rotate the card till your present heading (270 in the above example) is at the top, and the ADF needle will directly point you to the heading that you should fly to home in on a station, without having to do the math (120 in the above example).

Fun fact: NDBs use the same radio frequencies as AM radio. You can pick up some good music while navigating using an NDB!

4 Likes

So firstly it’s important to separate the ADF and the NDB.
The ADF (automatic direction finder) is the equipment on the aircraft and the NDB (non-directional beacon) provides a low to medium frequency to aid in approaches and navigation.

When an aircrafts ADF receiver is tuned to an NDB the direction of the NDB will be presented on a radio-magnetic indicator (RMI) with a compass rose which represents the fore and aft of the aircraft and the direction of the NDB relative to this.

The needle always points to the beacon and this is referred to as the QDM with the tail of the needle offering the QDR.

When homing to an NDB it is always important to make allowances for the drift angle created by the wind, as an NDB.

Their reliability in terms of accuracy is not as substantial at the VOR and they are incidentally less accurate at night, especially at dawn and dusk when the ionosphere is in transition.

1 Like

Thank you @CaptainSooraj @coffinpilot I’m starting to understand stand it.

1 Like

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.