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SSTV Sending Guide
Transmission Fundamentals
Transmission Process
- Image Preparation - Select and format the image
- Encoding - Application converts the image to audio
- Modulation - Modulate the audio via SSB
- Transmission - Transmit the RF signal
Required Devices
- Radio capable of SSTV transmission
- Microphone or audio output device
- SSTV encoder software
- Suitable antenna
Image Preparation
Recommended Specifications
| Parameter | Recommended Value |
|---|---|
| Resolution | 640×480 or 320×240 |
| Format | JPG, PNG, BMP |
| File Size | < 500 KB |
| Color Space | RGB or YCbCr |
Image Processing
- Adjust contrast for clarity
- Ensure proper brightness
- Remove unwanted noise
- Optimize sharpness and detail
Transmission Parameters
Choosing Mode
- Fast: M1 (110 seconds)
- Standard: M2 (145 seconds) or P3 (234 seconds)
- Quality: P5 (308 seconds) or P7 (390 seconds)
Power Settings
- Transmit at low power (5-10 watts)
- Use SSB modulation
- Monitor frequency to avoid conflicts
Audio Level
- Set about 70% on modulation meter
- Avoid overmodulation
- Avoid signal clipping
Transmission Frequency
International Active Frequencies
| Band | Frequency | Active Time |
|---|---|---|
| 20m | 14.230 MHz | All day |
| 15m | 21.340 MHz | Daytime |
| 10m | 28.680 MHz | When propagation allows |
Local Frequencies
Check specific SSTV frequencies in your region.
Transmission Etiquette
- Check Frequency - Make sure the frequency is clear
- Identify Yourself - Transmit your callsign
- Wait for Response - Allow time for others to reply
- Be Polite - Respect other users
- Follow Regulations - Know your local rules
FAQ
Q: Do I need a license? A: Yes, in most countries an amateur radio license is required.
Q: Can I transmit on any frequency? A: No, you must use frequencies allowed by your license.
Q: What are the power limits for transmission? A: It depends on your license class and national regulations.
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