Pocket25 - Mobile P25 Digital Radio Decoder

Pocket25 is an Android application designed primarily for decoding APCO Project 25 (P25) trunked and conventional radio systems. Built on the powerful DSD-Neo decoder engine, it brings professional-grade digital radio monitoring to your mobile device.

Download an APK here: https://pocket25.com

🎯 Primary Focus: P25 Systems

This application was built with P25 in mind and provides full UI support for:

• P25 Phase 1 (C4FM modulation) - ✅ Audio working perfectly
• P25 Phase 2 (TDMA/QPSK modulation) - ⚠️ Audio is choppy (upstream DSD-Neo limitation, see P25_PHASE2_AUDIO_ISSUE.md)
• Trunked System Following - Automatically follows voice traffic across control channels
• Conventional Monitoring - Manual frequency configuration
• RadioReference Import - Easy system configuration from RadioReference.com
• Talkgroup Filtering - Whitelist/Blacklist support for selective monitoring
• Real-time Call Display - Talkgroup, Radio ID, NAC, encryption status, emergency flags
• Site Details - WACN, System ID, Site ID, RFSS ID tracking
• Native USB RTL-SDR Support - Direct USB dongle support (no root required)
• Remote RTL_TCP - Connect to network-based RTL-SDR servers

🔧 Based on DSD-Neo Engine

Under the hood, Pocket25 uses the full DSD-Neo decoder, which means it technically supports many more digital voice protocols:

Protocols Supported by DSD-Neo:

• ✅ P25 Phase 1 (Full UI support, audio working perfectly)
• ⚠️ P25 Phase 2 (Full UI support, audio choppy - see P25_PHASE2_AUDIO_ISSUE.md)
• ❓ DMR (Tier I/II/III) - Untested, UI support limited
• ❓ NXDN (NXDN48/96) - Untested, UI support limited
• ❓ D-STAR - Untested, UI support limited
• ❓ YSF (Yaesu System Fusion) - Untested, UI support limited
• ❓ dPMR - Untested, UI support limited
• ❓ X2-TDMA - Untested, UI support limited
• ❓ ProVoice (EDACS) - Untested, UI support limited
• ❓ M17 - Untested, UI support limited

Important Note: While DSD-Neo will decode these protocols and you'll hear audio, the UI currently displays call information in a P25-centric format. Non-P25 systems may show incomplete or incorrect metadata in the interface.

📡 RTL-SDR Support

Pocket25 supports two methods for RTL-SDR:

1. Native USB (Recommended)

• Direct connection via USB OTG
• No root required
• Lower latency
• Better performance

2. Remote RTL_TCP

• Connect to RTL-SDR over network
• Useful for remote monitoring
• Works with existing rtl_tcp servers

🎬 Need Help: Sample Recordings Wanted!

I need your help to improve multi-protocol support!

To properly implement UI support for DMR, NXDN, D-STAR, YSF, dPMR, and other protocols, I need sample recordings of these systems in action.

How You Can Help:

Use rtl_tcp_echo to capture IQ samples:

# rtl_tcp_echo is a middleman application that:
# 1. Sits between DSD-Neo and RTL_TCP
# 2. Captures raw IQ samples to a .bin file
# 3. Allows perfect playback for development/testing

# Do the following:
# 1. rtl_tcp -a 0.0.0.0
# 2. rtl_tcp_echo -listen 0.0.0.0:1235 -record iq_recording.bin
# 3. Run DSD-Neo as RTL_TCP port 1235

What I'm looking for:

• ✅ DMR systems (Tier I, II, or III with trunking)
• ✅ NXDN systems (NXDN48 or NXDN96)
• ✅ D-STAR repeaters/conventional
• ✅ YSF (C4FM) repeaters/conventional
• ✅ dPMR systems
• ✅ ProVoice/EDACS systems
• ✅ M17 conventional

What makes a good sample:

• Contains actual voice traffic (not just idle/control)
• At least 60-90 seconds of activity
• Clear signal (minimal static/interference)
• Include system details known (frequency, system ID, etc.)

Where to send samples:

• Open an issue on GitHub with a link to your recording
• Include: Protocol type, frequency, location (general area), any known system details

With your samples, I can build proper UI support for all DSD-Neo protocols!

🚀 Features

Current Features (P25):

• ✅ Real-time P25 Phase 1 decoding (audio working perfectly)
• ⚠️ P25 Phase 2 decoding (audio is choppy - upstream DSD-Neo limitation)
• ✅ Trunked system following with automatic VC tracking
• ✅ RadioReference.com system import
• ✅ Talkgroup whitelist/blacklist filtering
• ✅ Manual frequency configuration
• ✅ Call history and activity log
• ✅ Site detail monitoring (WACN/SysID/Site/RFSS)
• ✅ Emergency call detection
• ✅ Encryption status indication
• ✅ Dual timeslot support (P25 Phase 2)
• ✅ Native USB RTL-SDR support
• ✅ Remote RTL_TCP support

Planned Features:

• 🔄 Full DMR UI support (talkgroups, color codes, talker alias)
• 🔄 NXDN UI support (call types, RAN, radio IDs)
• 🔄 D-STAR UI support (callsigns, routing info)
• 🔄 YSF UI support
• 🔄 Conventional scanner mode with frequency stepping
• 🔄 Encryption key loading
• 🔄 Per-call recording
• 🔄 GPS/Location decoding (LRRP)

📋 Requirements

• Android 8.0+ (API 26+)
• RTL-SDR compatible dongle (RTL2832U chipset)
  • R820T/R820T2 tuner recommended
  • USB OTG cable/adapter for direct connection
• Or: Access to an RTL_TCP server on your network

Supported RTL-SDR Dongles:

• NooElec NESDR series
• RTL-SDR Blog V3/V4
• Generic RTL2832U dongles
• Any rtl_tcp compatible source

🔧 Installation

1. Download the latest APK from https://sarahsforge.dev/products/Pocket25
2. Enable "Install from Unknown Sources" on your Android device
3. Install the APK
4. Grant USB permissions when prompted (for native USB mode)

📖 Usage

Quick Start (P25 Trunked System):

1. Import from RadioReference:

   • Tap "Import from RadioReference"
   • Search for your system
   • Select and import

2. Connect RTL-SDR:

   • Native USB: Connect dongle, grant permission
   • Remote: Configure host/port in Manual Configuration

3. Start Scanning:

   • Tap "Start" to begin monitoring
   • Application will automatically follow voice traffic

Manual Configuration (Conventional):

1. Navigate to "Manual Configuration"
2. Enter frequency in MHz (e.g., 771.18125)
3. Configure gain and PPM correction
4. Tap "Apply & Connect"
5. Tap "Start"

Talkgroup Filtering:

• Long-press any talkgroup in the call history
• Choose "Mute" to blacklist (ignore)
• Use Settings to manage whitelist mode

🛠️ Building from Source

Prerequisites:

• Flutter 3.10+
• Android NDK r26+
• CMake 3.22+

Build Steps:

# Clone repository
git clone https://github.com/SarahRoseLives/Pocket25.git
cd Pocket25

# Get dependencies
flutter pub get
cd example
flutter pub get

# Build APK
flutter build apk --release

🤝 Contributing

Contributions are welcome! Areas where help is needed:

1. Sample Recordings - See "Need Help" section above
2. Protocol UI Implementation - DMR, NXDN, D-STAR display logic
3. Feature Development - Conventional scanner, squelch, recording
4. Testing - Bug reports and feature requests
5. Documentation - Usage guides, protocol information

📄 License

This project includes:

• Pocket25 App Code: GPL-3.0
• DSD-Neo: GPL-3.0
• mbelib-neo: GPL-3.0
• librtlsdr-android: GPL-2.0

🙏 Credits

• DSD-Neo by arancormonk
• mbelib - AMBE/IMBE vocoder implementation
• librtlsdr - RTL-SDR driver library
• RadioReference.com - System database
• Copilot - Compiling DSD into an Android library and Flutter integration

📞 Contact

• GitHub Issues: Report bugs or request features
• Sample Submissions: Open an issue with recording details

⚠️ Disclaimer

This software is intended for authorized monitoring only. Users are responsible for ensuring compliance with all applicable laws and regulations regarding radio monitoring in their jurisdiction.