Product overview
The Xingkai ELRS TX 170Mhz TX High-frequency head is an external radio-control transmitter module for FPV drone control systems, based on the open-source ExpressLRS project. Its electronics combine ESP32 and SX127X main control components with an ESP8285 backpack chip. The module connects through a JR interface, and the host controller must support CRSF signal output. It accepts only CRSF signals by default and requires a 5-8.4V (2S) supply for operation.
Selectable refresh rates are 25Hz, 50Hz, 100Hz and 200Hz. Output power specifications list eight levels spanning 10mW to 2000mW, while power-switching instructions specify 100mW, 250mW, 500mW, 1000mW and 2000mW. In OpenTX, an ELRS LUA script is required to adjust power and refresh rate; it also controls the telemetry return ratio. The example controller configuration disables Internal RF, enables External RF with CRSF output, and uses channel range CH1-16 with receiver setting 00.
The transmitter ships with official ExpressLRS V3.5.0 firmware and no binding phrase configured. Pairing in this supplied configuration requires a receiver running firmware V3.0.0–V3.5.0 without a binding phrase. Wi-Fi provides a firmware-update function, while the LUA interface includes a binding-mode control. A matching antenna must be installed before the module is powered on. Applying power without that antenna will damage the transmitter’s PA chip, making antenna installation a required step before operation.
Specifications
| Specification | Value & conditions |
|---|---|
| Product type | ExpressLRS-based remote-control transmitter module |
| Frequency band | 170MHz |
| Output power options | 10mW/25mW/50mW/100mW/250mW/500mW/1000mW/2000mW |
| Power settings supported in operation | 100mW / 250mW / 500mW / 1000mW/2000mWPower switching via LUA script. |
| Refresh rate | 25Hz/50Hz/100Hz/200Hz |
| Input voltage | 5-8.4V (2S)2S supply. |
| Main control IC | ESP32+SX127X |
| Backpack chip | ESP8285 |
| Controller interface | JR interfaceHost transmitter must support CRSF signal output. |
| Accepted input protocol | Crossfire Serial Protocol (CRSF) onlyDefault configuration. |
| Internal RF mode | OFFOpenTX MODEL SETUP example; Internal RF. |
| External RF mode | CRSFOpenTX MODEL SETUP example; External RF. |
| Channel range | CH1-16OpenTX MODEL SETUP example. |
| Receiver setting | 00OpenTX MODEL SETUP example. |
| Antenna requirement | Install the matching antenna before applying power; otherwise the transmitter PA chip will be damaged.Before powering on. |
| Installed firmware | ExpressLRS V3.5.0 official firmwareAs shipped. |
| Binding phrase | None setDefault configuration. |
| Receiver firmware and binding requirements | Receiver firmware V3.0.0 – V3.5.0; no binding phrase configuredPairing with the transmitter in its supplied default configuration. |
| Configuration control | OpenTX LUA script required to modify output power or refresh rateOpenTX parameter adjustment. |
| Adjustable parameters | Refresh rate, return packet ratio and output powerUsing the LUA script. |
| Firmware update interface | Wi-Fi firmware updates |
