Over the years, many of the devices on the following pages have been sold openly to the general public by a number of firms, in flagrant disregard of Federal law prohibiting covert surveillance of private citizens except in very limited circumstances. One firm alone boasts of many "thousands of satisfied customers!"
The most common eavesdropping transmitters (telephone and room type) were originally designed to be operated in or near the standard FM broadcast band of 88MHz to 108MHz. These first-generation bugs would broadcast their 'overheard' conversations on standard FM frequencies. Anyone in range with an FM radio could listen-in or record the broadcast.
However, because the possibility of inadvertent discovery was so great, eavesdroppers quickly abandoned standard FM frequencies. They soon turned to frequencies just above and just below the standard broadcasting band.