How to make a walkie-talkie?
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Many have handheld radios. You can buy them in the store, however, the work of such radios often interfere with ground obstacles. But you can independently assemble a stationary walkie-talkie with low power and with an increased radius of action. Consider how to make a walkie-talkie with your own hands. For this you will need:
- Resistors - variable 47 kΩ and 10 kΩ
- P416 transistor
- Condenser 0.022 mF (2 pcs.)
- 4700 pF capacitors, 0.033 mF, 100 pF, 33 pF, 51 pF
- Trimmer capacitor 4-15 pF (2 pcs.)
- Throttle (L2) 20-60mkG
- Telescopic antenna
- Carbon microphone
- Copper wire, section 0.5 mm (40 cm)
- Power Battery (9-12V)
- SA1 switch
- A piece of getinaksa
- Power switch
- Textolite for mounting panel
- Aluminum sheet
- Wire cable
- Soldering iron
- Soldering Accessories
First you need to make the U-shaped chassis of aluminum sheet. It will need to locate controls. In this case, the power supply should be taken ready from the radio, radio or TV. It should give a constant anode voltage equal to 150-250V, as well as a filament voltage of 6.3V.Then, in accordance with the transceiver scheme, you need to assemble a walkie-talkie:
The coil of the transceiver circuit must be made of copper wire having a diameter of 1 mm. You need to take a bare wire, or even better - silvered. It should be wound on a rod having a diameter of 12 mm. The coil should contain 4 turns with a tap in the middle. In this case, the coil connection with the antenna is located on top of the coil circuit and contains 1-2 turns of the same wire. The chokes should be wound on the resistance of the sun-0,25. They should contain 0.5 m of PEL-0.15 wire.
As for the setting capacitor C, it can be taken with a ceramic dielectric, however, it is better if it has an air dielectric with one moving plate or with two fixed plates. Transformer Tr1 should be taken from the TV or lamp receiver. It should be noted that the high-resistance winding of the same transformer is used as a throttle DR6. If you are thinking about how to make a walkie-talkie out of the phone, and decide to use low-impedance telephone speakers, then you need to include them in the low impedance winding of this transformer. You should also note that if you want to use the phone in the circuit, as a radio, its use is impossible. But it is worth taking from him a carbon microphone.As a switch "Reception-Transmission" well-suited switches.
The next step is the creation and configuration of the antenna. Consider how to make an antenna for the radio. So, after the case of the radio is assembled, it will be necessary to make for the coil L1 exactly 11 turns of the wire with a thickness of 0.5 mm. This uses the band setting to a value of 27-30 MHz. If you need fine tuning of the range, then you must use the trim capacitors C1, as well as C2, when transmitting data when receiving data. In addition, the receive mode of the switch SA1 should be considered. Adjust the range using the factory control receiver. You can simplify this task by getting the headphones, so the setting will be much faster.
Having figured out how to make a walkie-talkie, let's move on to the next step — performing tuning in transmission mode. You must first set the position of the switches to get a loud hiss in the earpiece speakers. It is necessary to obtain a constant steady signal from the control transmitter used.It should be noted that in this case it is impossible to touch the coil L1. It is necessary to act with the help of a building capacitor C1. If the carrier signal coincides with the tuning frequency, the super noise should disappear completely. During switching in the control radio receiver to the transmission, the sound from the microphone should be well heard. When the desired results are achieved, it will be necessary to proceed to fastening the structure with special fasteners.
Fasten the communication coil and antenna
Using a homemade antenna, you should foresee the power of the antenna, because its further increase can damage the device or simply spoil it. It should be noted that the position of the coil connection with the antenna must be selected so that the power during the transmission of the signal was maximum and the reception is stable. And as a control transmitter and receiver, you can use a tuned pocket radio station. The waveform diagram for tuning the oscillatory circuits of the transmitter and receiver can be seen here:
It should be noted,that a number of radio frequency bands on the territory of Russia are reserved for military needs, therefore, the operation of amateur radio devices in these radio frequency bands is prohibited.
Also, over time, you can spend and some modernization of your radio. For example, it will not be superfluous to install a battery and a charger for it in it. You can still add cooling radiators for transistors and make an outlet for connecting an external microphone, headphones and an external antenna. With such additions, no store portable can compare with yours!