Unlike the Delrac system, Dectra was essentially the normal Decca Navigator system with the modification of several existing transmitter sites. These were located at the East Newfoundland and Scottish chains, which were equipped with larger antennas and high-power transmitters, broadcasting 20 times as much energy as normal chain stations. Given that the length of the chain baselines did not change, and were relatively short, at long distance the signal offered almost no accuracy. Instead, Dectra operated as a track system; aircraft would navigate by keeping themselves within the signal defined by a particular Decca lane.