Fran's escape from Calumet Lake had proved that he knew that his communications were intercepted and directionally analyzed.
"Long Ago, Far Away"
William Fitzgerald Jenkins AKA Murray Leinster
"Maybe those gadgets can be directionally spotted," he said.
"Long Ago, Far Away"
William Fitzgerald Jenkins AKA Murray Leinster
Equal pressure to the lifting power of the generator was exerted against the synchronizers at the power plant, but this force, not being concentrated directionally along an ultraviolet beam, involved a practical problem only at points relatively close to the synchronizers.
"The Airlords of Han"
Philip Francis Nowlan