Radtel RT-900

User Guide

Complete documentation for the Radtel RT-900 running stock firmware. Hardware specs, every menu item, keyboard shortcuts, and firmware internals — documented from the public source code.

RF Chip

BK4819

Display

1.77" Color LCD (160×128, ST7735S)

Memory Channels

256 (firmware supports 999)

TX Range

136–260 + 330–520 MHz

RX Range

18–999 MHz (super mode)

Output / Charging

8W / USB-C

MCU

BT32F0x (Cortex-M0, 72 MHz)

Memory

256 KB flash / 32 KB RAM

Controls

Twist power/volume knob

Antenna

SMA-Female

Battery

2200 mAh Li-Ion

RT-900 dual VFO display showing VFO A and VFO B with frequency, power, and signal indicators — RT-900 dual VFO display — color TFT showing VFO A and B with frequency, power, and signal indicators

Getting StartedPower on, display overview, VFO vs channel mode, basic TX/RX, band selection.Understanding the DisplayColor LCD layout, status icons, dual-channel display, signal indicators.Complete Menu ReferenceAll 55 menu items documented: name, function, options, defaults, and tips.Keyboard & ControlsKey matrix, side buttons, long-press actions, programmable functions.Scanning GuideFrequency scan, channel scan, tone scan, scan modes and resume methods.Memory Channels256 channels (up to 999 via firmware), saving, naming, managing, display modes.FM RadioFM broadcast receiver, 30 presets, auto-seek, band selection.Hardware ReferenceMCU, BK4819, color LCD, SPI flash, EEPROM map, GPIO pinout.Firmware ArchitectureSource tree, build system, task loop, startup sequence, CPS protocol.BK4819 Register ReferenceRF chip registers, FSK capability, modulation modes, tone tables.

About this guide

This guide covers the stock Radtel RT-900 firmware. Documentation is derived from the publicly available firmware source code at github.com/pdrbsts/radtel-rt-900-firmware. Some details may need verification on physical hardware.

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