Hifi AM MW Transmitter DIY Kit (with Quad Variable Capacitors) to Test Crystal Radio Receivers

Hifi AM MW Transmitter DIY Kit (with Quad Variable Capacitors) to Test Crystal Radio Receivers

Description:
AMT-MW207 medium wave transmitter is a simple amplitude modulation signal source. It is available to amateur electronics enthusiasts and radio enthusiasts.

It uses magnetic rods to emit electromagnetic waves, so it does not need an external antenna. It can be used to test ordinary medium-wave radios as well as crystal radios where the radio signal is insufficient. In addition, it can also be used as an instrument for debugging medium-wave radios.

1. It adopts a fully discrete circuit, which is especially suitable for students to learn the working principle, practical production and testing;
2. The variable capacitor uses the frequency modulation frequency amplitude modulation quadruple variable capacitor to connect the two amplitude modulation in parallel to obtain sufficient capacity. The quadruple is better than the common 223P amplitude modulated duplex variable capacitor material and feels better;
3. The base of the circuit board is glass fiber material, the thickness is measured about 1.5~1.6mm (0.06"). Single-sided white letters; solder pad with spray treatment can be directly soldered without grinding;
4. The circuit board obtained by the buyer may be slightly different from the sample in the picture, mainly due to the change of component position, but its circuit structure remains unchanged. We will make some minor and non-substantial changes, such as slight movement of component positions and minor adjustments to wiring, but we will not change the version number, nor will we re-take the photo and upload, hereby declare;
5. The instruction manual contains circuit schematics and board diagrams, as well as debugging methods and experience under amateur conditions. For more information and professional debugging methods, please download online or refer to relevant professional books;
6. The transmitter board is equipped with a 3.5mm headphone signal cable.

Effect:
This transmitter works well at an effective distance (0.5-1m/1.6-3.3ft). It has a high level of sound fidelity, especially with direct radio (such as our 636 and 68-1 single-pipe units). Listening with our self-made high-resistance dynamic earphones, the sound quality is not much different from the effect of direct playback by the player.

Specifications:
1. Frequency range: 525-1605KHz
2. Power supply voltage: 6V
3. Board size: 78 x 85mm/3.1 x 3.3" (LxW)
4. Transmission distance: about 1m/3.3ft for superheterodyne medium wave radio, and about 0.5m/1.6ft for direct amplified MW radios

Features:
- Simple circuit. It is only composed of commonly used transistors and resistance-capacitive inductive components, without audio transformers. It is easy to make
- Good sound quality. Within the rated transmission distance, its sound quality is close to the sound quality of FM radio, and the signal-to-noise ratio is good, especially the effect received by direct amplification radio is not much different from the direct playback modulation signal
- Without an external antenna (medium wave needs tens of meters), completely rely on the magnetic field leakage of the magnetic rod to affect the receiver, easy to achieve, but the transmission distance is close
- Many interfaces. Designed with all levels of transistors, quiescent current test jumpers, external power sockets, etc., easy to use and expand the function
- It supports external power supply and battery pack module (battery power supply board)
- With power supply indicator
- This version eliminates the jumper on the board and modifies the form of the test terminals to facilitate the connection of an oscilloscope, and the circuit remains unchanged, the effect is the same

Package Included:
- 1 x Set of MW transmitter

Note:
- Batteries are not included. 4pcs AA alkaline batteries are recommended.