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

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