Doppler Tracker
Real-time Doppler shift calculations for satellite radio
Select Satellite
MHz
Enter the downlink frequency
Quick Reference
| Satellite | Frequency |
|---|---|
| DIWATA-2 | 145.9 MHz |
| ISS (ZARYA) | 145.8 MHz |
| METEOR-M 2 | 137.1 MHz |
| NOAA-15 | 137.62 MHz |
| NOAA-18 | 137.9125 MHz |
| NOAA-19 | 137.1 MHz |
How Doppler Works
When a satellite moves toward you, its signal is compressed (higher frequency). When it moves away, the signal stretches (lower frequency).
The Formula:
Δf = -f₀ × (v/c)
- Δf = Doppler shift (Hz)
- f₀ = Base frequency (Hz)
- v = Range rate (km/s)
- c = Speed of light
Practical Tips:
- Transmit below the nominal frequency for uplink
- Receive above the nominal frequency for downlink
- Shift is greatest at low elevations
- Use automatic tracking when possible