Radio Distance 400 meters
Today on the Internet you can find many schemes of radio transmitters. For many months, almost half of them were repeated, but none of the schemes showed the necessary parameters. Long-range schemes were met, but stability left much to be desired. Stable schemes, in turn, had a range of not more than 100 meters. As a result, it was decided to assemble his scheme.Within a few days after a careful selection of radio components, a completely new radio beetle circuit was created. Thanks to the applied high frequency amplifier (UHF), it was possible to increase the range of the device to 400 meters. Tests done with the receiver of a mobile phone Nokia N95, a decrease or increase in frequency is observed, but only 0.5 fm! The power of the radio arm is about half a watt, tests were also carried out with double UHF, the range of action passed per kilometer,in the antenna circuit a free LED is lit. It was also noticed jamming several TV channels at a distance of 50 meters from the TV. I want to note that the TV channels went to bed completely, only one blue screen! Let's go back to our radio transmitter.In the transmitter and high-frequency amplifier, microwave transistors of the type Kt325v were used, the limiting frequency these transistors are over 1 gigahertz (1000 megahertz). The microphone took an electronic, from the Chinese tape recorder, pick up the microphone with great sensitivity. In the photographs the model of the beetle, later it will be transferred to the board, but in the cmd version. The circuit contains 6 turns of wire with a diameter of 1.2 mm, wound on a frame with a diameter of 8 mm. To configure the beetle, I advise you to use the simplest HF detector. With this detector, you can configure any bug in 5 minutes.You can tune the transmitter to any desired frequency in the FM limit using a variable capacitor. If desired, you can increase the number of turns of the circuit to 9 - and then the transmitter will operate in the range of am. My beetle caught on the frequency of 95 megahertz, although the beetle perfectly transmitted the signal in the band 94 - 96 megahertz (fm). It is convenient to use Chinese receivers, or a mobile phone receiver. Unlike other beetles, this one is perfectly caught by digital technology. The range as already mentioned is 400 meters <<honest>>.This range was obtained with direct visibility in the city. The sensitivity of the microphone is about 4–5 meters, the transmitter freely covers one room, even a whisper is heard. The antenna is a piece of wire with a length of 40 cm, powered by a 9-volt power cord.