News Item

Pilot's wrist strap aide

An unusual instrument was recently brought to our attention; it looks like an overlarge wrist watch on a strap.

Pilot’s wrist strap aide
An unusual instrument was recently brought to our attention; it looks like an overlarge wrist watch on a strap. The dial is about 7cm diameter and the markings have been put in by hand. An outer rotating dial is divided into 12 sectors; each sector has what appears to be the name of a place. Each sector also has a numeric entry, between 1000m and 10000m always rounded to within 500m. An inner dial has 12 corresponding sectors with the letters A-M without I. The owner did not know what this was but believed it to perhaps be an aide memoire for airfields and the numerals to be the wavelength of the associated beacons.
For a start let us assume it is a simple encryption device. The K sector is marked red so presumably the code location for the day is nominated and the dial rotated accordingly. A quick bit of Googling showed the names to certainly be places – in fact they are all locations within 100 miles of the north coast of Tunisia. Thanks to the depth of Google geographic knowledge it became clear that some spellings had shifted. Teburka on the dial is now Taburbah whilst others have new names such as Souk al Arba which is now Jundubah.
What about the numerals? Not wavelengths because no receiver would tune between 1000m and 10000m. My guess is altitude in metres. That makes it a device probably used by the Luftwaffe or possibly the Regia Aeronautica in the period 1942-1943. I reckon this is for air to ground communications. A fighter asked for his position might give it as “10km NE of Charlie at altitude Delta”. A simple code that changes each day but enough to be confusing to

  • 30 May 2017
  • HANG

Contact Us

The Royal Institute of Navigation
1 Kensington Gore
London
SW7 2AT

+44 (0)20 7591 3134
admin@rin.org.uk

E-Mail Communication

The Royal Institute of Navigation periodically sends out email updates to its membership and those who have subscribed to events and conferences run by the RIN. In doing so, the RIN takes all reasonable precautions to ensure that the emails are only sent to those who have requested them, and that no third party can make unauthorised use of any @rin.org.uk email address to send out mailings.If you receive unsolicited mail from any @rin.org.uk address then please inform us at admin@rin.org.uk and we will take appropriate action.

Join the RIN

You can apply for any category of RIN membership by completing the online membership application form and paying using our secure credit/debit card payment system.

Join Now