"rodger wilcox...over and out"

anybody know where this expession came from??
cartoons from the3 60's??

I don't know why 'roger' means 'understood' but 'wilco' is derived from 'will co-operate.'

Trained radio operators grind their teeth on hearing 'over and out.' In proper usage, 'over' means 'I've finished speaking for the moment and await your reply.' 'Out' is used to terminate a conversation.