📻 QAP — Quansheng Airband Project

RX-only firmware for the Quansheng UV-K5(8), dedicated to listening to air traffic

QAP = Quansheng Airband Project · Callsign: PU5XRM

🌐 Leia este README em Português (Brasil)

From left to right: booting, scanning and hold.

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Turn your Quansheng UV-K5(8) into a dedicated aviation scanner, focused exclusively on the 118–136 MHz (AM) band — tower (TWR), approach (APP), en-route (ACC), ATIS, ground (GND) and the 121.500 MHz emergency frequency.

⚠️ Receive-only. This firmware never transmits. Transmitting on aviation frequencies is illegal.

🧪 Evolving / experimental. This firmware is under active development — use at your own risk. Back up the factory firmware before flashing.

📡 By default, the firmware ships with Foz do Iguaçu (SBFI/IGU) frequencies pre-loaded in the scanner.

• 🎧 Dedicated AM reception on 118.000–136.975 MHz, with 8.33 / 25 kHz steps;
• 📡 Advanced AM AGC (32 levels, 3 dB hysteresis) — clean audio from aircraft close by or on the ground;
• 🔊 300–3400 Hz DSP band-pass filter — brings out the voice in ATC communications;
• 🔇 SNR-based squelch, not RSSI — the right approach for AM (carrier is always present);
• 🔄 Smart scan with ATC-optimized dwell time and priority channels (TWR/APP);
• 🖥️ Clean, dedicated UI on the ST7565 128×64 display (large frequency font, no visual clutter).

📋 Table of Contents

• 📻 QAP — Quansheng Airband Project
  • 📋 Table of Contents
  • 🖥️ Target Hardware
  • ⚙️ Features
    • ✅ Included
    • 🗑️ Removed (to free up flash)
  • 🔌 Installation — Flashing the Radio
    • 1. Download the firmware
    • 2. Back up the original firmware
    • 3. Flash with the Web Flasher
    • 4. Power on and listen
  • Building the Firmware
    • Build with Docker (recommended)
    • Build natively
  • 📁 Repository Structure
  • 📚 Documentation
  • 📥 Downloads
  • ⚖️ License and Credits

🖥️ Target Hardware

Item	Specification
Radio	Quansheng UV-K5(8) (and compatible variants)
RF chip	BK4819 (18 MHz – 1.3 GHz receive)
MCU	DP32G030 (ARM Cortex-M0, 64 KB flash)
Display	ST7565 128×64 (8 pages of 8 px)
Target band	118.000 – 136.975 MHz
Modulation	AM
Step	8.33 kHz / 25 kHz

⚙️ Features

✅ Included

• Full AM reception on the aviation band;
• Fast scan with ATC-optimized dwell time;
• Advanced AM AGC (32 levels with 3 dB hysteresis);
• 300–3400 Hz DSP audio band-pass filter;
• SNR-based squelch (optimized for AM);
• Airband-calibrated gain table;
• Priority channels (TWR/APP);
• S-meter / RSSI indicator;
• Configurable scan lists (1/2/3/ALL);
• Tri-frequency mode and remapped PTT key.

🗑️ Removed (to free up flash)

• Transmission (TX) — completely disabled in hardware;
• FM broadcast, NOAA, VOICE/Beep;
• DTMF calling/paging, AIRCOPY (RF clone);
• VOX, Alarm and other non-aviation features.

This frees ~23–30 KB of flash for the AM reception algorithms.

🔌 Installation — Flashing the Radio

1. Download the firmware

Grab the latest binary from the Releases section (the ...-firmware.packed.bin file).

2. Back up the original firmware

Use a flasher to save the factory firmware before any flashing. You will need it to restore the radio.

3. Flash with the Web Flasher

Use the web flasher (Chrome/Edge via Web Serial) with the downloaded .packed.bin file.

4. Power on and listen

Done — the radio boots straight into airband scanner mode.

⚠️ Use a quality data cable. An interrupted flash may require DFU recovery.

Building the Firmware

The C source lives in firmware/src/. The build is done with Docker (works on macOS Intel/Apple Silicon and Linux).

Build with Docker (recommended)

cd firmware
docker build -t uvk5-build .
docker run --rm -v "$PWD:/app" -w /app uvk5-build /bin/sh -c "make clean && make"

Build natively

Requirements: arm-none-eabi-gcc + python3 with crcmod.

cd firmware
make clean && make

The flashable binary is produced at firmware/build/firmware.packed.bin (flash < 64 KB, zero warnings with -Werror).

🔍 Full build + release guide in docs/build-release.md.

📁 Repository Structure

qap/
├── firmware/          # Firmware (C source, Makefile, Dockerfile)
│   └── src/           #   Source code (BK4819 drivers, UI, scan, AGC…)
├── docs/              # Architecture, UI, Brazilian airband frequencies
├── plans/             # Implementation plans (roadmap)
├── CHANGELOG.md       # Build history
├── CNAME              # qap.romildo.net domain
├── LICENSE            # Apache 2.0
└── NOTICE             # Credits to the base projects

📚 Documentation

Document	Contents
docs/arquitetura.md	Technical decisions, BK4819, flash budget
docs/ui-design.md	ST7565 128×64 UI specification
docs/frequencias-airband-brasil.md	Brazilian ATC frequencies (TWR/APP/ACC) + suggested scan
CHANGELOG.md	Build history with hash and dated binary

📥 Downloads

Each build publishes a dated binary with sha256 hash in the Releases section:

• Current build (2026-08-16): 20260816T21h08-firmware.packed.bin
• Hash: 0054e37e2fee0c2c80f99567e39d9f81c7702b481dff2efd55f97f7886a2614c
• Size: 51,938 bytes (flash < 64 KB ✓)

Direct link to the latest release:

https://github.com/romildodcm/qap/releases/latest/download/firmware.packed.bin

⚖️ License and Credits

Distributed under the Apache License 2.0 — see LICENSE and NOTICE.

Fork based on:

• DualTachyon — original implementation;
• OneOfEleven;
• egzumer;
• Armel/F4HWN;
• miramir/uv-k5-firmware — base of this fork.

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QAP — Quansheng Airband Project · Aviation reception with the UV-K5 · PU5XRM

This project is for listening only. Do not transmit on aviation frequencies — it is illegal and dangerous.