Probably, every novice radio amateur has a special interest in a radio receiver, which consists of only a few parts and is assembled in just a couple of minutes. To do this, it is enough to have school knowledge. One model of the detector receiver, "Komsomolets", was produced by the Soviet industry, then - only as a visual aid for schools. Assembling a detector receiver is a useful workshop for novice radio amateurs.
It is necessary
paper tube (sleeve), insulated copper wire, diodes, capacitor, headphones
Instructions
Step 1
Take any paper tube with a diameter of 14 to 21 mm. On top, wind about 300 turns of copper wire with a diameter of 0.2-0.35 mm with an insulating coating such as PEV-1, PEV-2, PBD and so on. In addition, make small twists elbows every 45-60 turns. To ensure that the first and last turns do not unwind or fall off, secure them with rubber bands. Thus, make a sectional inductor.
Step 2
Connect in parallel to the coil a series-connected point diode of the D2 or D9 series with your favorite letter index and high-resistance head phones of the TON-2 or TA-4 type. After that, connect the external antenna and ground to the created closed circuit. Also, a capacitor with a capacity of 2500 to 4000 pF can be connected to the headphones, which should significantly improve their sound. If you want to present your first radio to a small audience, then the headphones are replaced with a resistor with a resistance of 10-15 kOhm, to which a low-power amplifier with a small speaker is connected.
Step 3
Tune the receiver to a radio station. Of the large number of electrical vibrations in the antenna, the receiver should select only one, i.e. the radio station we want to hear. This is done using a grounded conductor, which is moved along the terminals of the coil, which was done during its manufacture. The larger the number of turns of the coil, the longer the received wavelength. Also, for more accurate tuning, you can use the selection of a capacitor with a capacity of 100 to 300 pF, which is connected to the antenna and ground. Since the selection of a capacitor takes quite a long time, it is better to use a variable capacitor. This simple radio is mainly aimed at novice radio amateurs, therefore it does not differ in particular accuracy and purity of sound.
