2. the variable capacitor uses a double variable capacitor, two in parallel to get enough capacity;
3. adopts double-sided board circuit, the board base is fiberglass material, the thickness is measured about 1.5~1.6mm, the pads are sprayed with tin treatment, and can be directly soldered without polishing;
4. This product has been modified n times so far (mainly to modify the circuit board wiring, circuit unchanged), and is still in the process of continuous improvement. Usually small non-substantial modifications, such as slight movement of component positions, wiring minor adjustments will not change the version number, and will not not re-photograph upload, hereby declared;
5. The instructions contain circuit schematics and circuit board diagrams, as well as amateur conditions of debugging methods and experience, the need for more information and professional debugging methods please buyers to download or refer to the relevant professional books on the Internet; mainly changes in the location of components, the circuit structure remains unchanged.
6. Transmitter with a 3.5mm headphone signal cable, does not contain batteries.
1. Simple circuit. Only commonly used transistors and resistive and capacitive components, without audio transformer, easy to make;
2. Good sound quality. In the rated transmitting distance, the sound quality is close to FM broadcasting, with good signal-to-noise ratio, especially the effect of receiving with a repeater is not much different from that of directly broadcasting modulated signals;
3. no external antenna (medium wave need tens of meters), rely entirely on the magnetic field leaked by the magnetic bar to affect the receiver, easy to realize, the transmission distance is relatively close;
4. many interfaces, designed with waveform test end, audio socket, external power socket, etc., easy to use and expand the function;
5. can be connected to an external power supply, also install the battery for independent use.
Frequency range: 525~1605kHz
Supply voltage: 6V
DC power connector: 5.5*2.1mm
Circuit board size: 78mmx85mm (L×W)
Transmitting distance: about 1 meter for super-aberrant medium wave radio, about 0.5 meter for direct and crystal radio.
Instructions for use:
1. Insert the external 6V DC power supply (internal positive and external negative) into the CZ1 socket on the board, or insert the 6V battery pack connector into the Battery interface, paying attention to the positive and negative poles should not be mistaken.
2. Insert a signal cable into the CZ2 socket on the board and connect it to the modulation signal source, which can be used with a cell phone, player, etc. It is recommended to use a player, as cell phones have strong interference with medium-wave radios.
3. Turn the potentiometer knob to turn on the radio, the effect of this potentiometer is similar to the radio volume potentiometer.
4. Turn on the radio, search for the transmitter's signal to listen. It can also be operated the other way around, tune the radio receiving frequency to a position where there is no radio station, then turn the dial of the transmitter to change the transmitting frequency until the radio plays the transmitter's signal.
1. This product only in the desktop range has a better effect, when the radio is too far away from the transmitter (more than 1 meter), the effect is a serious decline, the performance of the sound is small signal-to-noise ratio deterioration;
2. Increasing the supply voltage can make the waveform amplitude increase a lot, but the actual usable launch distance does not change much;
3. transmitter potentiometer control modulation system, if the modulation is too large to make the radio demodulation distortion, the transmitter itself will deteriorate the waveform, the correct use is summarized after many times after the use of a suitable position, so that the modulation system as large as possible and can try to ensure the quality of the sound, every time you use it to turn to this position can be, do not treat it as a radio volume potentiometer to frequently adjusted to adjust to and fro;
1 x Module
1 x 3.5mm headphone signal cable
The antenna magnet bar may be bent, but it has no effect on the usability. Antenna magnet bar texture is very brittle, when knocking collision will break.
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3.All package need to wait 30 days,Please take care it.Less than 30 days,we can't take a refund.
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