frequency-lookup

# Frequency Lookup for WaveCap-SDR

This skill helps find frequencies and band plans for various radio services.

## When to Use This Skill

Use this skill when:
- Finding frequencies for marine/aviation/amateur bands
- Looking up broadcast stations by location
- Verifying frequency allocations
- Discovering what's on a frequency
- Planning SDR monitoring scenarios
- Creating new recipes for specific bands

## Common Frequency Bands

### VHF Marine (156-162 MHz)

**Channel 16 (156.800 MHz)** - International Distress/Safety/Calling
**Channel 9 (156.450 MHz)** - Recreational calling (US)
**Channel 6 (156.300 MHz)** - Intership safety

Full band plan: https://www.navcen.uscg.gov/marine-communications-channel-table

### Aviation (118-137 MHz)

**121.500 MHz** - Emergency frequency
**Typical ranges:**
- Tower: 118.0-121.4 MHz
- Ground: 121.6-121.9 MHz
- ATIS: Varies by airport

Find local frequencies: https://www.airnav.com

### NOAA Weather Radio (162-163 MHz)

**WX1: 162.550 MHz**
**WX2: 162.400 MHz**
**WX3: 162.475 MHz**
**WX4: 162.425 MHz**
**WX5: 162.450 MHz**
**WX6: 162.500 MHz**
**WX7: 162.525 MHz**

Coverage map: https://www.weather.gov/nwr/

### FM Broadcast (88-108 MHz)

**US band:** 88.1-107.9 MHz (odd tenths only)
**Europe/Asia:** 87.5-108.0 MHz

Find local stations:
- https://radio-locator.com
- https://fmscan.org

### Amateur Radio (Ham)

**2 meters:** 144-148 MHz (FM repeaters typically 145-147 MHz)
**70 cm:** 420-450 MHz
**HF bands:** 3.5, 7, 14, 21, 28 MHz

Repeater directory: https://www.repeaterbook.com

### Public Safety / Trunking

**VHF:** 150-174 MHz
**UHF:** 450-470 MHz, 806-824 MHz

Database: https://www.radioreference.com

## Online Resources

**RadioReference.com** - Comprehensive frequency database
- Trunked systems
- Talkgroup IDs
- Local agencies

**SignalWiki** - Signal identification
- Decode unknown signals
- Modulation types

**WebSDR** - Remote SDR receivers
- Listen without hardware
- Check propagation

**FlightAware/FlightRadar24** - Aviation tracking
- Find airport frequencies
- Track aircraft

## Usage Examples

### Find Marine Channels
```
VHF Marine channels are spaced 25 kHz apart
Channel number = (Frequency - 156.000) / 0.025
Channel 16 = 156.800 MHz
Channel 9 = 156.450 MHz
```

### Find Local FM Stations
Visit https://radio-locator.com and enter your ZIP code

### Find NOAA Weather
Find nearest transmitter at https://www.weather.gov/nwr/

### Find Aviation Frequencies
Visit https://www.airnav.com and search for airport code (e.g., KSEA)

## Integration with WaveCap-SDR

After finding frequencies, create a recipe:

```yaml
recipes:
  my_frequencies:
    name: "My Frequencies"
    capture:
      center_hz: 156800000  # Center on Ch 16
      sample_rate: 250000
      gain_db: 35
    channels:
      - {name: "Ch 16", offset_hz: 0, mode: "fm"}
      - {name: "Ch 9", offset_hz: -350000, mode: "fm"}
```

Or use presets for quick tuning.

## Band Plan Quick Reference

| Service | Frequency Range | Typical Use |
|---------|----------------|-------------|
| AM Broadcast | 530-1700 kHz | Radio stations |
| Ham 160m | 1.8-2.0 MHz | Amateur HF |
| Marine SSB | 2-4 MHz | Long-range marine |
| Ham 80m | 3.5-4.0 MHz | Amateur HF |
| Ham 40m | 7.0-7.3 MHz | Amateur HF |
| Ham 20m | 14.0-14.35 MHz | Amateur HF |
| Ham 10m | 28-29.7 MHz | Amateur HF |
| CB | 26.965-27.405 MHz | Citizens Band |
| Ham 6m | 50-54 MHz | Amateur VHF |
| FM Broadcast | 88-108 MHz | Radio stations |
| Aviation | 118-137 MHz | Air traffic control |
| Ham 2m | 144-148 MHz | Amateur VHF |
| Marine VHF | 156-162 MHz | Maritime |
| NOAA WX | 162.400-162.550 MHz | Weather |
| Ham 70cm | 420-450 MHz | Amateur UHF |
| GMRS/FRS | 462-467 MHz | Personal radio |

## Files in This Skill

- `SKILL.md`: This file - frequency reference and lookup guide

## Notes

- Frequencies vary by country (this guide is US-centric)
- Always check local regulations before transmitting
- Some frequencies require licenses (ham, marine, aviation)
- SDR receiving is legal, transmitting requires proper licensing
- Band plans change - verify with official sources
- Use RadioReference.com for most comprehensive database