A simple DIY radio zoo

On the Internet, you can find a huge number of circuits radio circuits. Some schemes are too complicated and require adjustment, others include defective radio components, and others do not work at all! I bring to your attention a scheme of a bug, which can be assembled by both an experienced radio amateur and a beginner in this business. Let's consider this scheme:
>img src="https://sdelaysam-svoimirukami.ru/images/19/919-prostoy-radiozhuchok-svoimi-rukami.jpg" alt="simple radio fly with your own hands" title="simple radio fly with your own hands">
Do not pay attention to the dotted line. To make a bug, we need the following details:
  • VT1 - kt315 with any letter index (if you want to increase the range the actions of a bug, it is better to use a microwave transistor, for example kt325 or kt368, the import transistor s9018 is perfect);
  • C1, C4 - 47… 68nf;
  • C2, C3 - 10pf;
  • R1 - 33 kOhm;
  • R2 - 100 Ohm;
  • Oscillating circuit L1 - 8 turns of copper wire with a diameter of 0.3 ... 0, 5 mm on the helium pen rod, shake gently,(I dropped a finished coil from a broken radio).
  • M1 is an electret or condenser microphone.
 simple radio radio with one's own hands
We put the board in the solution and wait until the extra copper disappears. After the board is removed, we remove it, rinse it with running water, remove the varnish and lud m of it: a simple radio bug with your own hands
Next, we solder the parts in accordance with the scheme. Attention, when installing parts on the board, do not overheat them, otherwise they will fail! Especially neatly refer to the installation of the VT1. I want to say a few words about the antenna connection, the signal is fed from the emitter of the transistor, which makes the bug's working frequency more stable. The schematic in assembled form:
 simple radio bug with your own hands
A bug can be fed in the range from 1.5 to 9 volts.
simple radio button with your own hands
Any of these batteries are suitable for powering the circuit. I used a AAA finger-type battery for a more compact bug. You can also use a 3 volt “pill”. If you feed the circuit from the crown (9 volts), then you should include a resistor R3 of 100 Ohms in the circuit. Carefully solder the battery to the bug. As an antenna, you can use an insulated wire 30cm long, but practice has shown that its absence will not greatly affect the range of reception of the circuit. All, the bug is ready!
 simple radio bug with your own hands
Now turn on the radio and look for the frequency of our bug. The signal from it can be caught at a frequency of 88-108 MHz. I have this frequency was 92.2 MHz.If the bug "does not communicate", then try to move the turns of the coil L1 - this should help to solve the problem. At a supply voltage of 1.5 volts the range of reception is 30 meters, if you increase the voltage to 3 volts, the range of reception will increase up to 100 meters. Also, this circuit has another application - audio transmitter. Suppose you need to output sound from the phone to the tape recorder, but the latter does not have the audio input function. No problem! In this situation, this scheme is very useful. Almost all tape recorders have a radio reception function (FM radio), which we will use. Remember about the dotted line on the scheme of a bug? We exclude the microphone M1 from the circuit, connect the capacitor C5 to a capacitance of 10 mph, connect the mini-jack plug 3.5mm (minus the jack) to the common, left / right to minus the capacitor to the minus of the capacitor and minus the power, and transfer the sound from the phone to any one the radio is in range of the transmitter! With proper installation of the parts, the circuit starts working immediately. You can apply these products for a variety of purposes: from listening to the premises and to wireless transmission of sound. And this is my article coming to an end, all the luck in repetition!

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