Introducing three new radio navigation aids for Mosquito crews

Navigation in the Project Overlord server for Mosquito crews has always been pretty easy.

You’ve got a second crew member to share the workload with, and even if you’re flying solo you’ve always got the radio beacon at Ste Croix to home onto if you get lost.

Unfortunately for our players, the existing radio beacons are fictional ones we created so players could use the Mosquito’s radio navigation equipment.

Happily, we’ve spent the past couple of weeks researching actual historical radio direction-finding (RDF) beacons to enhance the realism of the Project Overlord navigation experience.

Although these changes won’t affect aircraft other than the Mosquito, anything that enhances the historical accuracy of our missions is always of interest to the Project Overlord development team.


A de Havilland Mosquito FB.VI pictured flying at low level in the DCS World combat flight simulation game

New radio beacons

We are introducing three new beacons at these locations:

  • Bernay Elektra-Sonne (semi-fictional)
  • Haine (next to Manston)
  • Whitlands (near Lyme Regis, Dorset)

These are simplified in DCS due to game engine limitations. They function as non-directional beacons (NDBs) that can be tuned on the Mosquito’s R1155 direction-finder.

They are marked on the map for the Allies, and the Bernay beacon is also visible to the Axis side as well, although currently no Axis aircraft can tune the beacon. Approximate locations are shown on the DCS F10 map extracts below.

As you can see from the map extracts, the new beacons are very widely spaced apart.

Although you can no longer use them for airfield homing unless you’re flying to Manston, this means greater navigational accuracy can now be achieved because there are more beacons to use.

Above is an example of the new markings on the F10 map in-game.

In this example you can see the name of the beacon (Haine RDF), the identifying letter it transmits in Morse code (F, plus the dot-dash code itself that you will hear in game) and the beacon’s frequency.

Note that the frequency is given in the units of the time as used in the DCS Mosquito: 3.6 megacycles per second. In modern units that would be 3.6 megahertz, or MHz.

Using the beacons in DCS

The beacons can only be used by Mosquito crews (solo pilots or multicrew pilots and navigators).

Tune the beacon frequency and identify it. You will hear the Morse code over the R1155. Once identified, you can pinpoint your bearing from the beacon. Take a second bearing from a different beacon to obtain a fix.

Use Reflected Simulations’ Mosquito radio tutorial if you are unfamiliar with the aircraft’s radio navigation equipment. 

You can also use the original operating instructions for the R1155 in paragraphs 97-106 of Air Publication 2548. (PDF, 95 pages)

History of the real-world beacons

The Haine and Whitlands beacons date back to the early 1940s when the Royal Air Force was looking for ways of improving its navigation, especially at night.

Although various types of radio beam and beacon were in use by 1941, these were generally limited to ranges of 150 miles. A new type of directional, high power, long range beacon was needed so bomber crews could fly along them to their navigational waypoints and targets.

Air Publication 1136 Volume 3, the history of RAF signals during World War II, has this to say about the beacons:

Three high-power beam transmitters were consequently installed at Cransford, Fulstow and Haine. The aerial systems were rotatable so that the beam could readily be aligned on any bearing to within an accuracy of less than 10 seconds of arc. The Cransford and Fulstow transmitters operated on a frequency of 36 megacycles per second and that at Haine on 36.4 megacycles per second.

Above is a list helpfully sent to PO by a historian, showing radio track guide beacons’ locations and operating frequencies.

We have taken some creative licence with the frequencies, as they are all outside the R1155 radio DF set’s normal operating range.

Instead of 36MHz, ours operates on 3.6MHz. We have also used 3.8MHz as our beacons are not directional, meaning they would otherwise interfere with each other.

Have fun flying and navigating!