To study radio waves in a school physics course, you need a walkie-talkie. It may also be needed if your children decide to play scouts - what kind of scout is without radio communication? If you had a pair of factory walkie-talkies and one became completely unusable, you can not buy a new set, but make a walkie-talkie with your own hands
It is necessary
- P416 transistor
- Variable resistor 47 kOhm
- Resistor 10 kOhm
- 2 capacitors 0.022 mF
- Capacitor 0.033mF
- 4700pF capacitor
- Capacitor 100 pF
- 33pF capacitor
- 51pF capacitor
- 2 trimmer capacitors 4-15 pF
- Choke (L2) 20-60 μH
- Carbon microphone
- High impedance phones (headphones)
- Telescopic antenna
- 40 cm of copper wire with a cross section of 0.5 mm
- 9-12 V battery
- Switch (SA1) - 2 positions for 2 groups of contacts (double toggle switch is possible)
- A piece of getinax or PCB for the mounting panel
- Installation wire
- Power switch (not shown in the diagram)
- Toy radio transmitter
- Instruments
- Soldering iron
- Nippers
- Pliers
- Tweezers
- Drill
- Drill
Instructions
Step 1
Assemble the parts according to the diagram. Tune coil L1 to a range of 27-30 MHz. Its winding data are as follows: 11 turns of the lead 0.5 mm are wound on a blank with a diameter of 10 mm. Fine tuning to the range is carried out by trimming capacitors C1 (receive mode) and C2 (transmit mode), taking into account the fact that the switch SA1 on the diagram is in the receive mode. The range is adjusted using a control receiver (for example, a factory-made children's radio communication device). The easiest way to do this is in transfer mode. Switching the switch to receive mode, achieve a loud hiss in the headphones by adjusting the transistor mode with a variable resistor.
Step 2
Without touching the coil L1, use the tuning capacitor C1 to achieve stable reception of the signal of the control transmitter (the same children's radio communication device). If you are making a walkie-talkie instead of a damaged one, adjust it as you have.
Step 3
The design of the case can be any, it depends on the dimensions of the parts. If the housing is metal, the antenna must be protected from contact with the housing by a reliable insulator. Plexiglass can be used as an insulator.
