RadioMaster ER4 2.4GHz ExpressLRS PWM Receiver

Short Description:

RadioMaster ER4 is a 2.4GHz ExpressLRS PWM receiver with four output channels, 10mW telemetry power, 4.5–8.4V DC supply, a 15cm antenna and Wi-Fi configuration.

Product Name: RadioMaster ER4 2.4GHz ExpressLRS PWM Receiver
Product Type: 4-Channel PWM Receiver
Frequency Range: 2.4GHz
PWM Outputs: 4 channels
Telemetry Power: 10mW
Input Voltage: 4.5–8.4V DC
Receiver Protocol: ExpressLRS
Dimensions: 30 × 15 × 5mm
Antenna Type: 15cm high-sensitivity antenna
External Battery Voltage Detection: 4.0–35V DC

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Product Detail

FAQ

Technical Highlights

Four PWM Output Channels

The ER4 provides four PWM output channels. RadioMaster states that the receiver can drive four servos simultaneously.

2.4GHz ExpressLRS Control Link

The receiver uses the 2.4GHz ExpressLRS system. Its specified 10mW telemetry power belongs to the RC link and is not an FPV video-output rating.

External Voltage Telemetry

External battery voltage can be detected over a 4.0–35V DC range. This sensing range is separate from the receiver's 4.5–8.4V DC power-supply range.

Compact Receiver with Wi-Fi Configuration

The ER4 measures 30 × 15 × 5mm and supports Wi-Fi firmware updates and WebUI configuration.

Receiver and RF Specifications

Model	ER4 2.4GHz ELRS PWM Receiver
Receiver Protocol	ExpressLRS
Operating Frequency	2.4GHz
PWM Outputs	4 channels
Telemetry Power	10mW
Antenna	15cm high-sensitivity antenna
Connector Pitch	2.54mm
Configuration	Wi-Fi updates and WebUI configuration supported

Electrical and Physical Specifications

Receiver Power Supply	4.5–8.4V DC
External Battery Voltage Detection	4.0–35V DC; voltage-sensing range, not receiver supply voltage
Dimensions	30 × 15 × 5mm
Manufacturer-Listed Weight	3.0g
Manufacturer-Listed Pre-installed Firmware	ExpressLRS 3.3.0; confirm the actual firmware of the supplied batch
Firmware Target	RadioMaster ER4 2.4GHz PWM RX

Selection and Installation Notes

Use a 4.5–8.4V DC supply for the receiver. Do not use the 35V voltage-detection limit as a receiver power-input rating.
Match the ER4 to a suitable 2.4GHz ExpressLRS transmitter and confirm firmware and binding settings before installation.
Connect servos according to the four PWM channel markings and confirm the intended channel configuration.
The ER4 is an RC receiver; it does not transmit FPV video.

FAQ

Is the ER4 an FPV video transmitter?

No. The ER4 is a 2.4GHz ExpressLRS PWM receiver. Its 10mW specification refers to telemetry power, not video output power.

How many PWM outputs does the ER4 provide?

It provides four PWM output channels. RadioMaster states that it can drive four servos simultaneously.

Can the receiver be powered directly from a 35V battery?

No. The receiver power-supply range is 4.5–8.4V DC. The 4.0–35V DC specification applies to external battery-voltage detection only.

Does the ER4 support wireless configuration?

Yes. RadioMaster lists Wi-Fi firmware updates and WebUI configuration for the ER4.

B2B Procurement FAQ

What model should be specified in a purchase inquiry?

Specify RadioMaster ER4 2.4GHz ELRS PWM Receiver, four PWM channels and the required quantity. Confirm the installed firmware version and package contents for the quoted batch.

Which specifications should be checked for integration?

Confirm the 4.5–8.4V receiver supply, servo connections, antenna placement and whether the project uses the external battery-voltage sensing input.

Are price, MOQ and lead time predetermined?

Price, minimum order quantity, availability and lead time must be confirmed during quotation.