Made in 1980 by Polytechnic Marine and sold by Decca, the ‘Decca Marine 801’ is a satellite navigation receiver that worked with the Transit satellite system to determine a user’s latitude and longitude. This unit represents a time when satellite navigation technology became more widely available for civilian and commercial use.

The Transit satellite system was developed by the United States Navy to provide accurate location information to Polaris ballistic missile submarines. It became operational in 1964.

In the 1980s, thousands of warships, freighters and private watercraft used Transit. This was partly due to changes in how consumer electronics were manufactured. For instance, the Decca 801 offered new standard features at a reduced price. This receiver was sold to marine markets including fishing and commercial. Standard features included automatic input of course and speed, making the continuous dead reckoning display extremely accurate. This feature benefited sailboats, fishing boats and other vessels whose operating patterns often required frequent change in course and speed. (Supply 12 v. DC. Inputs for SPD and HDG. Antenna connection.) The Transit system was made obsolete by the Global Positioning System (GPS) and ceased service in 1996.