"They've spoted my broadcasts by d/f. 'What's d/f?' 'Direction finder. Then they turned off the current in each building in the neighborhood for five seconds…building by building…until the broadcast stopped. Now they know I'm in this house, but they don't know which apartment.' I put on my shirt and jacket. 'Goodnight, Lizzie. I wish I could kiss you.' She clamped her arms around my nectk and gave me a smacking kiss; all warmth, all velvet, all giving. I tried to push her away."
From "The PI Man".
By Alfred Bester.
1959.