FAB

Another of my childhood favourites was "Thunderbirds". This is a future science-fiction TV series made in the UK performed in supermarionation puppets. A super millionaire American family, Jeff Tracy and his five sons, live on an island. The Tracys form a secret organization, International Rescue, and with their super hi-tech land, sea and space vehicles, Thunderbirds 1,2,3,4 and 5, they come into rescue emergencies anywhere on earth to save human lives.

I loved the puppets, the future settings and the vehicles, and also how they talked. It was a British TV programme, but the Tracys talked with American accent. Their accent had great contrast with the London agent Lady Penelope and her butler Parker, also the characters of the same TV series. Some of the phrases the Tracys used were unfamiliar to me, and I found them amusing.

When the Tracy brothers were in their rescue missions, they were on their vehicles so they had to communicate on radios. At the end of their conversation, they always said, "FAB", which seems to mean the same as 'Roger' or 'heard and understood'. (And 'Roger' is also a phrase I learned off a TV drama show.) I used "FAB" when I was playing with walkie-talkie with my friends and brothers. Cool.

Now, whatever does FAB mean?
There seems to be several explanations to the word, and not a definite answer.

Fully Advised, Briefed
Fully Acknowledged Broadcast
Fabulous

The first two makes acronyms FAB, and on some sites it is said that these acronyms were used by US army radio operators during WWII.
The third 'fabulous' was abbreviated to 'fab', and was quite popular in the 60's in the UK.

Considering that the Tracys were Americans (and the father Jeff was an ex-astronaut), and the brothers use it when they are radio communicating, the acronyms seem plausible for the meaning of FAB.

By the way, Lady Penelope's pink Rolls-Royce is FAB1, her yacht FAB2 and her race horse is FAB3. I prefer to think that these FABs owned by Lady Penelope are abbreviated "FABULOUS"es.