One of the systems which were used along the Namibian and South African coasts was a series of marine radio beacons situated along the coastline and which provided vessels navigating in our waters with a means of obtaining radio bearings. Six of these stations were situated in Namibia and twenty four in South Africa.
The system operated in the MF (medium frequency) band (280 – 315 KHz) and had a range of between 25 and 100 nautical miles. Since the bearings obtained were great circle bearings, they had to be corrected for convergency before they could be plotted on a Mercator chart. The systems two main shortcomings were:

  • The signal was prone to distortion when it passed over the coastline. Radio waves travel more slowly over land than over the sea.
  • At night the sky waves interfere with the ground waves, causing fading when the two signals are received simultaneously. The sky waves also cause bearing errors.

The distribution of radio beacons and radar transponders was as indicated above.