John Redpath, who went on to become the senior design engineer working on Decca's last generation of marine receivers, describes the Mk 52 set.

"The MK52 was another ‘badge engineering’ exercise in the height of competition from a number of cheaper Decca receivers that were nibbling at the edges of the Company’s lucrative hire business in the mid to late ‘80s.  £2,000 a month was at one time the typical income for one of the high end Decca receivers such as the MK21 or MK30.  When the MK53 was launched it had a retail value of typically £2,500 and rental options were also available although these were greatly reduced from those previously charged.  Whilst the MK53 was far more sophisticated than anything the company had previously made, it was still far cheaper to produce than any of its predecessors but, despite this, its sale and rental prices were still too high to compete against sets emerging from Shipmate (Rauff & Sorenson RS4000),Vigil (Mars Marine) and Thomas Walker.

Racal entered an agreement to badge engineer AP (Philips) product as Decca Yacht Navigators and for the professional market the APs were reboxed as the MK51.  However, soon afterwards an agreement with Polytechnic Electronics, who traded under the name Navstar SA, saw the re-badging of the product that became the MK52.  Unlike the AP product which was basically a ‘Lane Ident’ receiver, the MK52 was a full four channel receiver and could be produced for sale at a price that was approximately half that of the MK53.

The receiver was boxed in the same case and similar chassis to the original Decca Yacht Navigator but there, the similarity ended. The content from here on in was all from a company called Polytechnic Electronics.

The clever thing that Polytechnic had done was to design a 4 channel receiver that didn’t used expensive crystal filters but tuned solid state circuits.  They also used an (improved) early Decca idea of using binary rate multipliers to provide the heterodyne frequencies".

Front view. Click on image to enlarge.

Channel board.

Rear view.

Power supply.

All photos in this table by John Redpath

Contributors and Credits:
1) John Redpath <john.redpath(at)charlotteville.co.uk>
2) David Jones <djones(at)litramfg.com>
 

June 8/09