Goshyda 9V2A 530-1600KHz Medium Wave AM Transmitter Instruction Manual

1. Introduction

This manual provides detailed instructions for the setup, operation, and maintenance of your Goshyda 9V2A 530-1600KHz Medium Wave AM Transmitter. Please read this manual thoroughly before using the product to ensure proper functionality and safety.

Figure 1: The Goshyda Medium Wave AM Transmitter circuit board.

2. Safety Information

Always observe the following safety precautions to prevent damage to the device or injury to yourself:

• Ensure the power supply meets the specified requirements (9V2A DC, internal positive, external negative). Incorrect power supply can damage the device.
• Do not operate the transmitter in wet or damp conditions.
• Avoid touching the circuit board components while the device is powered on.
• Keep the device away from strong magnetic fields.
• Do not attempt to modify the circuit beyond the described adjustments.
• Use appropriate antenna wiring as specified to prevent signal interference or damage.

3. Product Overview and Components

The Goshyda Medium Wave AM Transmitter is designed to convert audio input into a medium wave AM signal. Key functional blocks include:

1. Sound Amplification: Components R2, R3 serve as sound source access resistors. SW1 is the volume potentiometer. IC1 is the sound amplifier chip. C9 acts as sound coupling capacitors, while C11 and C12 are sound bypass capacitors. R1 and C8 form an RC filter circuit. R5 and D1 are power indicators.
2. Oscillation Source: Q1 forms a common-base modulation transformer oscillation circuit, generating high-frequency signals of equal amplitude. The CV can be adjusted to a frequency range of 530-1600 KHz. R10 and C19 constitute the positive feedback network. C18 is a high-frequency bypass capacitor, ensuring a common base and circuit operation. C16 and C17 provide power filtering and high-frequency bypass. R7, R8, and R9 are bias resistors.
3. High-Frequency Amplification: Q2 further amplifies the high-frequency amplitude signal from Q1. C20 is the coupling capacitance, and C21 is the high-frequency bypass capacitance. R11 and R12 are bias resistors. B2 is the high-frequency broadband conduction inductance, with its secondary output providing high-frequency voltage.
4. High-Frequency Modulation: C22 and C23 are sound capacitors. SW3 is adjusted to obtain the correct sound voltage. R15 is a negative feedback resistor. SW2 and R14 are bias resistors, with SW2 adjusted to improve sound quality.
5. Filter Network: L2, L3, C26, and C27 form a low-pass network. This network filters out high harmonics, ensuring the waveform is nearly sinusoidal and properly matched to the antenna.

Figure 2: Detailed view of specific components on the transmitter board.

4. Setup Instructions

Follow these steps to set up your Medium Wave AM Transmitter:

1. Power Supply Connection:

   Connect a 9V2A DC power supply to the 5.5mm interface. Ensure the power supply has an internal positive and external negative polarity. (Note: Power supply is not included and must be provided by the user.)
2. Antenna Connection:

   Prepare a household wire with a diameter of 1.5 or 2.5 square millimeters and a length of 2-5 meters. Connect this wire to the antenna terminal on the circuit board. (Note: Antenna wire is not included and must be provided by the user.)

3. Audio Input Connection:

   Connect your audio source (e.g., mobile phone, MP3 player) to the 3.5mm audio input jack on the transmitter using a 3.5mm audio cable.

   

   Figure 3: Transmitter board with connection points and example accessories.

5. Operating Instructions

Once the transmitter is set up, follow these steps for operation:

1. Power On: Connect the power supply. The power indicator (D1) should illuminate.
2. Adjust Transmission Frequency:

   Use the CV adjustment on the oscillation circuit (Q1) to set the desired transmission frequency within the 530-1600 KHz medium wave band. A small screwdriver may be required for fine-tuning.
3. Adjust RF Transmit Power:

   The RF transmit power is adjustable from 20-500 MW. Adjust the power for optimal performance within a 5-10 meter range for local use. Avoid excessive power if not necessary.

4. Adjust Audio Volume:

   Use the SW1 volume potentiometer to adjust the input audio volume. Ensure the audio signal is not overdriven or too low.

5. Optimize Sound Quality:

   Adjust SW3 to achieve the correct sound voltage. Further refine the sound quality by adjusting SW2 and R14 (bias resistors) as needed.
6. Testing:

   Use a medium wave AM radio receiver to tune into the set frequency and verify the transmitted audio quality.

6. Maintenance

To ensure the longevity and optimal performance of your transmitter:

• Keep the device clean and free from dust. Use a soft, dry cloth for cleaning.
• Store the transmitter in a dry environment, away from extreme temperatures.
• Regularly check all connections for security.
• Do not expose the circuit board to moisture or corrosive substances.

7. Troubleshooting

If you encounter issues with your transmitter, refer to the following common problems and solutions:

8. Specifications

9. Warranty and Support

Information regarding specific warranty terms and customer support contacts for the Goshyda 9V2A 530-1600KHz Medium Wave AM Transmitter is not available in the provided product data. Please refer to the seller's or manufacturer's website for the most current warranty and support information.

For general inquiries, you may visit the Goshyda Store on Amazon.