From the puppet cult TV series by Gerry Anderson, 'Thunderbirds'. Alternative for 'Loud and Clear' in radio transmissions. Apparently according to Gerry on the thunderbirdsarego.com website, 'Fabulous' was a buzzword of the 60's, often shortened to 'Fab' and for the show it became F.A.B
by Andy Derrick September 07, 2005