Note: The SI4732 system is a customized version based on Russian firmware. To ensure firmware compatibility with multiple hardware devices, the developers have displayed all buttons by default on the page. However, not all buttons in the system will actually be functional (different devices may support different functions). If a button is grayed out, it means that the function is not supported, which is normal. Please do not modify the device firmware yourself.

Description:
The ESP138 is a dual-system radio, utilizing the TEF6686 system (open source project) and the ESP32-SI4732 system architecture. It integrates the TEF6686 chip with high-fidelity Bluetooth functionality, offering exceptional selectivity and ultra-high sensitivity. The SI4732 supports Air Band (AIR) and Single Sideband (SSB), as well as Bluetooth 5.0 dual-mode. Equipped with a 2.4-inch touchscreen, numeric keypad, large-capacity battery, and aluminum alloy body, it offers both professional reception and portability.

Specification:
Controller: ESP32-WROOM-32U
Bluetooth: JL high-performance chip
Screen: 2.4-inch IPS touchscreen (320x240)
Speaker: 40mm full-range speaker
Antenna: Built-in 820mm telescopic antenna
External antenna port: 3.5mm external antenna port
Battery: 3.7V / 2500mAh lithium polymer battery
Interface: Type-C (5V/2A charging, supports data upgrades)
Casing Material: Aluminum Alloy
Dimensions: 120 × 63 × 25mm (excluding antenna)
Weight: Approximately 350g

Note: The CIP it is equipped with is original.

Features:
1. [Dual-System Reception]
The ESP138 is a dual-system professional radio, utilizing the TEF6686 system (open source DSP algorithm) and the ESP32-SI4732 system (full-band coverage), operating independently. While the radio is powered on, a single click of the power button allows you to switch between operating systems. Note:
The TEF6686 system supports open-source firmware upgrades, while the SI4732 system's firmware is locked and cannot be flashed.
2. [TEF6686 System]
The TEF6686 system supports FM/LW/MW/SW bands, DSP noise reduction algorithms (CEQ, EMS, iMS, and PACS), and full RDSs data display, specifically for high-fidelity broadcast reception.
3. [SI4732 System]
The SI4732 system supports FM/LW/MW/SW bands, as well as the aviation band (AIR 118-138MHz) and single-sideband (SSB), meeting the needs of amateur radio enthusiasts. Supports ATT attenuation, AGC gain control, bandwidth (BANDW) step switching, and single-sideband fine tuning (BFO).
4. [Bluetooth Dual Mode Support]
You can use your phone's Bluetooth to connect to the radio, using it as a Bluetooth speaker. You can also stream received broadcasts or audio to Bluetooth headphones or speakers via Bluetooth.
5. [Powerful Configuration]
The speaker features a 40mm long-throw, full-range speaker, delivering powerful bass and clear highs. It also includes a built-in 820mm extra-long telescopic antenna and a 3.5mm external antenna jack on the bottom. A numeric keypad allows for quick frequency entry, while a rotary knob allows for tuning. Note: When using the touchscreen on the SI4732 system, the physical number keys and menu button are disabled (the Bluetooth/volume buttons function normally).

Frequency:
In TEF6686 mode:
Coverage: FM (65-108MHz) / LW (144-513kHz) / MW (520-1720kHz) / SW (1700-27000kHz). Air Band and SSB are not supported.

In SI4732 mode:
Coverage: LW (153-500kHz) / MW (520-1710kHz) / SW (1730-30000kHz) / FM (64-108MHz) / SSB (1730-30000kHz) / Air Band (50-200MHz, native support for 118-138MHz).
Supports Air Band (AIR) and Single Sideband (SSB) without the need for additional equipment.

Note:
Open source firmware upgrades are supported in TEF6686 mode. However, the firmware in the SI4732 system is locked and cannot be flashed.

Package Included:
1 x Radio
1 x Type-C Charging Cable

Q&A:Q: My device suddenly shut down when it showed 30% battery remaining?A: This is indeed how the battery display is designed. 30% battery corresponds to approximately 3.3V. In reality, the battery has no power left, and the chip will operate under low voltage, which is abnormal, causing it to shut down as a protection mechanism. Simply charge the device to restore its functionality.