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Built Right In. California, with its high divorce rate (half as many as marriages), high incomes and highly sophisticated industries, is the hard-heartland of the U.S. bugging industry. Espionage is so commonplace in oil, chemical and aerospace companies that many California executives begin to fidget if a visitor so much as sets a briefcase beside him. Another busy Bugsville is Miami, where horseplayers, weekending couples and Latino intrigue support a host of electronic moonlighters who make eavesdropping gadgets in their spare time and sell to anybody.
In fact, official surveillance organizations, such as the FBI, have expertly bugged rooms spotted through leading hotels. When they want to tune in on a guest, they ask the hotel management to steer him to one of these sonic studios. If the guest balks, an agent needs only a few minutes to sneak up and secrete several bugs in the room assigned the visitor; then a team of technicians moves into an adjoining room to set up listening and recording apparatus.
Siphoned Sound. Private detectives —fortunately—cannot count on cooperation from hotel managements, but they can often get into a victim's room by bribing subordinate employees. If the job is important and well paying, they try to plant at least three bugs to catch low-toned conversations in all parts of a room; then tiny cameras, often hidden in radiators or air conditioners, can be triggered by radio control. The most advanced still cameras advance their own film and adjust their shutters to different lighting conditions, but for a really fancy job a TV camera is the thing. Though it takes hard-to-hide coaxial cable, the TV set need be only eight inches long and an inch or so in diameter; its lens can peer through an inconspicuous opening such as a heating duct or recessed light fixture.
If the sleuth cannot get into the target room, he will usually work from an adjacent room or corridor, where he may be able to slip a bug into an electrical outlet or heating duct, which are often back-to-back. Otherwise, he may drill a small hole through the wall and poke a thin plastic tube into it, just short of the far surface, so as to siphon sound waves into a microphone next door.
One last resort for frustrated bug planters is a special mike attached to a sharp spike; driven through the wall, it vibrates with the surface on the far side. But, like esoteric radar beams that pick up the vibrations of distant window glass, spike mikes are apt to be defeated by stray noise unless conditions are perfect.
Smart victims can fight back. One fairly effective weapon is a broad-band radio receiver that gives a squeal if a bug is transmitting near by. Another anti-bug is carried around the room while the occupant keeps talking loudly; if he hears his own voice in the earphones, he is listening to the output of a hidden bug. The best defense is a thorough, periodic search by an electronic exterminator. Otherwise, anyone who suspects he is being bugged should talk in low tones and keep a radio or TV squawking loudly. One spy fiction dodge, turning on the shower, is useless since the "white sound" of falling water can be electronically filtered out from human voices.