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Decca Navigator System
Videos
The Decca Navigator System was a hyperbolic radio navigation system that allowed ships and aircraft to determine their position by using radio signals from a dedicated system of static radio transmitt
The display panel of a Decca Navigator Mk 12 (ca. 1962). Decca position coordinates were directly displayed by four decometers and these were plotted
The display panel of a Decca Navigator Mk 12 (ca. 1962). Decca position coordinates were directly displayed by four decometers and these were plotted on a conventional chart that had been over-printed with Decca lattices.
Decca Navigator Mk. 21, with the Decometer dials prominent.
Decca Navigator Mk. 21, with the Decometer dials prominent.
Decca receiver, Mk.51 seen in the National Museum of Scotland
Decca receiver, Mk.51 seen in the National Museum of Scotland
An ap Decca receiver Mk II from the 1980s that could be purchased instead of leased. It could store 25 waypoints.
An ap Decca receiver Mk II from the 1980s that could be purchased instead of leased. It could store 25 waypoints.
LORAN
Videos
LORAN was a hyperbolic radio navigation system developed in the United States during World War II. It was similar to the UK's Gee system, but operated at lower frequencies in order to provide an impro
Decca Navigator System
…The system used phase comparison between pairs of low frequency signals between 70 and 129 kHz, as opposed to pulse timing systems like Gee and LORAN. This made it much easier to design receivers using 1940s electronics, and operation was simplified by giving a direct readout of Decca coordinates…
The AN/APN-4 was an airborne LORAN receiver used into the 1960s. It was built in two parts to match the UK's Gee system, and could be swapped with Gee
The AN/APN-4 was an airborne LORAN receiver used into the 1960s. It was built in two parts to match the UK's Gee system, and could be swapped with Gee in a few minutes.
AN/APN-4 LORAN in RCAF Canso (PBY) aircraft
AN/APN-4 LORAN in RCAF Canso (PBY) aircraft
R-65/APN-9 in a B-17G aircraft
R-65/APN-9 in a B-17G aircraft
The signal from a single LORAN transmitter will be received several times from several directions. This image shows the weak groundwave arriving first
The signal from a single LORAN transmitter will be received several times from several directions. This image shows the weak groundwave arriving first, then signals after one and two hops off the ionosphere's E layer, and finally one and two hops off the F layer. Operator skill was needed to tell these apart.