One day I was approached by a man with such a problem – a neighbor in the country got its infinite wiretapping Rickets fm and other pop music. Of me wanted to make a suppressor of the fm band. Collecting and checking a couple of circuits of the network was very dissatisfied with the results: jamming in a small radius and only a couple of stations (+-3MHz). In this case and would be over, but people already asked for help! Offered any money. Had once again taken up the soldering iron and invent something new. As a result, obtain a circuit that is still able to score the entire fm band at a distance of about 50m (depending on antenna). Scheme works as follows: the generator on a KT368 works in the regime of strong self-excitation of hf, and generates a lot of harmonics near the fundamental frequency contour – 100 + 10 MHz.
This mode is defined high-capacity capacitor 12pik. For the normal generation, he is usually put no more than 10pik, so to adjust better to install podstroechnik. Next rf signal amplified by two broadband cascades. In the first you can put any rf transistor and the second must be something powerful. Naturally stands out on the radiator. The antenna is a piece of wire or telescope, but to ourselves not to fall under interference – the signal was fed through a shielded cable.
Simply create a carrier, although broadband will be small. Powerful broadcasters can and get through it. In order to become impossible for a normal listening to music, by modulating the rf signal generator simply pee-pee on K561LA7, K561LE5 or similar. Eats jammers from a psu with a voltage of 12V or higher, at a current of at least half ampere. Fairly simple diode bridge rectifier with capacitor and a couple of thousand microfarads. Of course this is not a super military jammers, but set goals that muffler fulfilled.