Homemade simplest radio

Single chip microcomputer STM32L151CCU6

0201 package SLP0603 ESD electrostatic diode 5V one-way ESD

Homemade simplest radio

(1) Structure:
There are three knobs on the front of the bottom plate: the left side is a 365pf air variable, used for tuning. The middle is a splitter for the old ore machine, with 8 lugs for switching the 8 taps of the tuning coil to Find the impedance matching with the detection input to get the maximum detection output. The right side is also a 365pf air variable, which is used to adjust the resonant frequency of the frame coil. The cylinder coil is made of a glass tube with a diameter of 46mm and a length of 120mm. (Basically equivalent to the air-core coil, almost no loss of electromagnetic waves). The above is wound with 0.09*32 strands of enameled wire. The antenna coil is next to the tuning coil, there is no gap in the middle. The tuning coil starts tapping around 20 地 from the ground. Pump one head every 10 ,, draw a total of 8 heads, and connect to the splitter in the future. The antenna coil is wound around 40 匝, 20 匝, 30 抽 one. The main contact of the splitter is connected to the end of the active ore. Equivalent to the anode of the diode.
The three arms above the frame antenna are 600mm in length and the lower arm is 650mm in length. The long part is used to fix it on the base. The upper three arms have 18 lower slots and the lower arm. There are 19 lower trunk slots. When winding, the winding is started from the lower arm near the middle lower slot, and the wire is wrapped with 0.09*42 goose silk, which is wound around 18匝 and 1/4匝, and the tail end is fixed below. The last slot in the arm of the arm.
The active ore is my own (previously published in the production method). The head is bigger and very beautiful. The transformer behind is used to match the horn speaker. The speaker is 5W8 ohm.
In the test, it is connected to the double-pressure detection form, and then connected to the half-wave detection. Compared with the full-wave detection, there is no difference in feeling. In the end, in order to get the best effect, each 2AP9 and active ore are connected in parallel. Can be converted to each other.
Two output terminals are designed, one with high-impedance earphones, the terminal is located on the left side behind the bottom plate, the other is connected to the primary side of the transformer (impedance matcher), and the second is connected to the horn speaker. The two output terminals are equipped with The detection device, each equipped with various filter capacitors. The transformer is also the original self-made power transformer once for 220V twice for 10V*2, double-wire winding, 220V side connected to the detection output, twice connected to the horn speaker, horn It is 5W8 ohms. Each connection is evenly connected with a 1mm thick enameled wire.
(2) Effect:
In a quieter and safe environment, no external antenna is connected, only one ground wire is connected (I am connected to the heating device. It can be heard within 4m, and it is very clear. Connect the external antenna (I am connected to the cable TV) Shielded online), it is heard within 5m. It is very efficient. This is one of my favorite works.