I have always been baffled by why Simon Dee kept saying in interviews and articles that, just before the Caroline ship sailed north on 3-July-64, the transmitter crystals were exchanged between the two ships. Both stations continued broadcasting on their original frequencies of 1520 (north) and 1493 (south) so, although this may have been the plan, I don't see how it could have happened.

His claim has been repeated in various histories. For example, Ray Clark in his 2014 book says "the transmitter crystals were exchanged" (page 77) and frequency changes had taken place overnight (page 78).