Advice 1: How to make a walkie-talkie with your own hands

To study radio waves in a physics class required radio. She might need in that case your kids decided to play scouts — the scout without a radio? If you have had a couple of factory radios, and one came in complete disrepair, you can not buy a new set, and make the radio their hands
It is advisable to make two of the same radio
You will need
  • Transistor П416
  • The variable resistor 47 kOhm
  • Resistor 10 kOhm
  • 2 capacitors 0,022 MF
  • Capacitor 0,033 MF
  • Capacitor 4700 pF
  • A capacitor of 100 pF
  • Capacitor 33 pF
  • Capacitor 51 pF
  • 2 trimmer capacitor, 4-15 pF
  • Choke (L2) 20-60 mcg
  • Carbon microphone
  • High-impedance phones (headphones)
  • Telescopic antenna
  • 40 cm of copper wire 0.5 mm
  • Battery power for 9-12 In
  • Switch ( SA1) — 2 position for 2 groups of contacts (double toggle)
  • A piece of Micarta or PCB for mounting panel
  • Mounting wire
  • The power switch (not shown in the diagram)
  • Toy radio
  • Tools
  • Soldering iron
  • Clippers
  • Pliers
  • Tweezers
  • Drill
  • Drill
Assemble the parts according to the scheme. Adjust coil L1 for the range 27 to 30 MHz. Its winding data are as follows: 11 coils of about 0.5 mm is wound on a disc with a diameter of 10 mm. fine tuning range is carried out with trimming capacitors C1 (receive mode) and C2 (transfer mode) given the fact that the diagram of the switch SA1 is in the receive mode. The adjusting range is held at the reference receiver (for example, child radioprogramm device fabricated). This is easiest to do in a transmission mode. Switching the switch in receive mode, until a loud hiss in the headphones, adjusting the mode of the transistor a variable resistor.
Assemble the parts according to the scheme
Without touching the coil L1 and trimmer capacitor C1 until you get a good signal reception control transmitter (of the same child radios). If you make a walkie-talkie instead of a spoiled, customize it according to available.
The housing design can be any, it depends on the dimensions of the parts. If the casing is metal, the antenna must be protected from contact with the housing of a reliable insulator. As insulator can be used plexiglass.
The component values marked on the diagram

It is advisable to collect 2 similar radios.

Sometimes for reliable operation of the radio station you want to pick up the transistor by replacing it.
Useful advice
Instead of the telescopic antenna can use a piece of stiff copper wire or copper tube. The length of the wire or tube is 0.5 m.

Installation of the radio is performed on the circuit Board of dielectric material. It can be printed and mounted. Perhaps the use of three-dimensional mounting.

Tuning the radio is held in connected and fully extended the antenna. During the configuration and operation of the radio is not to touch the antenna with your hands.

In the diagram, the applied high frequency transistor structure p-n-p, but it can be replaced by any other low-power RF, including the structure of the n-p-n, for example KT315. In this case, you must reverse the polarity of the power source reversed.

Advice 2: How to set a car radio

Automobile radios are a great communication method between vehicles. These devices are very relevant for truck drivers, drivers of passenger transport and for other car owners which often move around the track. They help not only to warn other road users approaching the traffic police patrol, but also to help the driver to call for help if necessary.
How to set a car radio
Purchase car radio. If your car is provided a niche for its installation, you can easily put it there. If no, it is set in absolutely any place. Thus it should be easily accessible and have excellent ventilation to prevent overheating of the device.
Do not mount the radio , where is the path of the air flow from the air conditioner or stove. Quite often the radio is mounted under the glove box or between the seats of driver and passenger.
Determine the most convenient from your point of view, a place to mount a car radio there and mark the holes to install the mounting brackets. It is supplied with the device. Don't forget to think about protecting your radio from theft. It may have a removable slide or be embedded in front panel.
Drill holes for fasteners. Before you start drilling, check to see whether you relate to the wiring of the car. To restore it after damage does not always work easily and quickly.
Determine what your automotive radio power supply. If the wrong connection of the radio to a power source will decrease the output power of the device. It is best to connect the radio to the battery directly, namely, to its terminals (plus and minus).
Use to connect the radio to the powered copper wire. Eliminate crossing the power wire with the alleged sources of interference. Use a shield made of ferromagnetic wire, which is protected from oxidation.
Select the correct installation location of the antenna after mounting a car radio in the car. Ideally, you'll be able to put the antenna on the roof in the center of the cab. Connect the antenna and the radio.
The setting of the equipment trust professionals.

Advice 3: How to make a simple radio

Walkie talkie has many. Buy them in the store is not a problem, but their work very often interfere with ground obstacles, wires and metal objects. But you can collect stationary radio low power with increased range. She can stand at home or at the cottage, and a good antenna will increase the range of 5-10 km in all conditions.
How to make a simple radio
You will need
  • - parts from an old tube radio or TV;
  • - soldering iron;
  • accessories for soldering;
  • - aluminium sheet.
Make of aluminium sheet chassis, U-shaped according to the dimensions of your existing parts. Provide its vertical front panel from aluminium. It will be possible to place the controls. The power supply is take from the radio, television, gramophone, etc. Must be given a constant anode voltage 150-250V, and the filament voltage of 6.3 V.
Assemble the transceiver circuit
Collect the radio for the transceiver circuit, as shown in the figure. Coil loop transceiver is copper wire with a diameter of 1 mm. Wire take naked, and even better - silvered. For the range of 27-30 MHz it is wound on the rod 12 mm in diameter, and contains 4 turns with a tap in the middle.
Coil connection antenna contains 1 to 2 turns of the same wire and is on top of the coil circuit. Chokes DR1, Др2 and Др3 wrap the resistance of VS-0,25 resistance not lower than 1 mω. They contain 0.5 m of wire PEL-0,15.
The condenser settings With you can take the ceramic 4-15 pF (trimmer), but it's better if it will be with an air dielectric with one movable and two fixed plates. If you are going to work only on one particular channel, the tuning knob to supply is not required.
TP1 transformer (audio transformer TVZ or similar output tube) take the tube from the receiver or TV. High resistance winding of the same transformer used as a choke Др6. If you want to use low-resistance headphones, turn them in nizkoomnyj winding of the transformer. The following diagram shows the inclusion of high impedance phones.
Microphone use coal. For example, from the telephone. The switch "Reception - Transmission" approach, the app switches. They can be replaced by any other 3 of the contact group and 2 positions.
Configure the radio. Do the setting in reception mode. The variable resistor R3 until multi-stable noise at all positions of the capacitor settings. If you cannot achieve this, pick up the capacitance of the capacitor C3 in the range from 100 to 1000 pF. The setting range is carried out by the condenser, as well as pinching and spreading the coils of the loop coil. When the frequency settings carrier signal multi noise in the phones must be completely turned off. When you switch on the transmission to control the radio needs to be clearly heard the sound from the microphone.
The position of the coil connection antenna pick up so that the power PI of the transmission was maximum, and the reception is stable. As a control receiver and transmitter, you can use a pre-configured pocket radio.
Keep in mind that the radio is designed for amplitude modulation and in conjunction with the FM radio will not work.

The diagram shows the connection of dipole antenna. But you can connect and pin. For this purpose one end of the coil connects to the chassis, and the connection to the antenna is through a coaxial cable (e.g., RK-1).

In the scheme used lamp 6Ф1П. But it is possible to collect a radio and a double triode (for example, 6Н1П or 6Н3П). The chain C6-R6 from the circuit is excluded. You can collect the radio and on two separate lamps, used as a triode half of the lamp 6Н7 or 6Н8, and as pentod - 6Ж4 or 6Ж8.
Is the advice useful?