Happymodel ES900TX Transmitter Module is a long-range wireless data transmission device operating at 915 MHz, developed based on the open-source ExpressLRS software. The module features long range, stable performance, low latency, and convenient Plug & Play operation. The aluminum heatsink is specially designed to ensure stable module operation at high power output and provides reliable cooling.

Key Features:

• Frequency: 915 MHz (also supports 868 MHz for the EU).
• Long Range: Provides reliable communication over long distances.
• Stable Performance: Maintains a reliable connection even under intensive use.
• Low Latency: Fast data transmission for precise control.
• Easy to Use: Plug & Play operation.
• Compatibility: Supports most OpenTX-based radio controllers, including Radiomaster TX16S, Boxer, TX12, Jumper T12, and T16.
• Cooling: Features a dedicated heatsink and the option to install a fan for efficient cooling at high power output.

Technical Specifications:

• MCU: ESP32 + ESP8285
• Dimensions: 55 × 39 × 11 mm
• Weight: 9.2 g (without antenna)
• Antenna Connector: SMA jack
• VCC Input: 5–13 V, recommended 5–9 V
• Frequency: 915 MHz or 868 MHz (for the EU)
• Maximum Output Power: > 30 dBm (a cooling fan is recommended when operating above 27 dBm)
• Firmware Update: via Wi-Fi or ExpressLRS Configurator