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Navigation

ADF is typically used to find NDB stations – however, coverage and reliability can

vary.

NDBs are part of airways and have a greater range than locators, which are approach beacons
for airports. LO at Billund has been closed down, and there are no more NDBs in Denmark. But

they still exist abroad, and questions may still arise for the Danish Transport Authority's test.

Some of the shorter-range locators used for landing procedures still exist, but they are being
phased out and replaced by GPS. The frequencies used in Denmark are from 320 kHz to 400.5

kHz (MF).

9.9.2.1 ADF Bearing

To make the relative bearing for something that can be used on the map, you
have to do a little 'calculating'. Once you have been given a bearing, you are only

halfway there. It is a magnetic bearing to the radio beacon.

You cannot use that for anything immediately - you do not know where you are.

But let's assume that you have
o
been given a bearing of 270 .

Then you know that you are
o
270 to the radio beacon.

The direction from the beacon

o
to you must then be 180
o
o
opposite the 270 , i.e. 090 .

Now you can draw a line on the

map from the beacon in the

o
direction 090 . You must be
somewhere on that line.

Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 874