Choosing FPV radios & batteries gets tricky when a four-channel receiver, an eight-channel fixed-wing receiver, a signal-focused receiver, and a DJI transmitter booster appear in the same group. The useful shortcut is to identify the job first: channel count, airframe type, receiver features, or transmitter path.
These four choices split into three ExpressLRS receivers and one 2.4G booster module. They are not interchangeable, so the right pick depends more on the equipment around the part than on price alone.
Quick take
- RadioMaster ER4: A compact ExpressLRS receiver for small aircraft, boats, cars, and models using four simultaneous PWM channels.
- RadioMaster ER8: The fixed-wing choice when support for eight servos and eight channels is central to the setup.
- RadioMaster RP3 V2: The receiver to consider when antenna diversity, a built-in TCXO, and WiFi firmware updates are priorities.
- FPV Radio Signal Booster: The specialized route for a DJI RC transmitter, with a listed 2.4G 2W output and 5-15V operating range.
Price comparison
The listed prices span $17.49 to $40.99, a $23.50 difference between the lowest and highest choices.
| Product | Listed price | Price bar |
|---|---|---|
| RadioMaster ER4 ExpressLRS 4-Channel Receiver | USD 17.49 | |
| RadioMaster ER8 ExpressLRS 8 Channel Receiver | USD 40.99 | |
| RadioMaster RP3 V2 ExpressLRS Receiver | USD 22.49 | |
| FPV Radio Signal Booster Amplifier Module | USD 33.73 |
Decision matrix
- Need a compact receiver for a small model? The ER4 description names small aircraft, boats, cars, and other models requiring lightweight functionality.
- Building around fixed-wing servo control? The ER8 is specifically described for fixed-wing users and supports eight servos.
- Prioritizing receiver-side signal features? The RP3 V2 combines antenna diversity, a built-in TCXO, LNA, PA, and WiFi updates.
- Using a DJI RC transmitter? The booster is the relevant match because its title and description identify that transmitter family directly.
Product notes
RadioMaster ER4 ExpressLRS 4-Channel Receiver
The RadioMaster ER4 is the clearest fit for a compact model that needs four simultaneous PWM channels. Its description specifically names small aircraft, boats, cars, and other models where lightweight functionality matters. ExpressLRS support and the stated ultra-long-range capability also suit a setup already built around that system. The concrete limitation is channel count: ER4 supports four PWM channels, while the ER8 is the receiver described with eight-channel and eight-servo support. That makes ER4 a focused choice rather than a broad fixed-wing servo solution. Its compact design and straightforward four-channel role keep the decision simple when the model's controls fit within that layout.
RadioMaster ER8 ExpressLRS 8 Channel Receiver
The RadioMaster ER8 is aimed at fixed-wing users who need an eight-channel receiver with support for eight servos. That makes its role distinct from the four-channel ER4 and gives it a clear place in more control-heavy fixed-wing setups without requiring a performance ranking between the receivers. The limitation is practical size and specification scope: the ER8 is described at 43 × 30 × 15 mm and 16.5g, with a DC 4.5-8.4V power supply. Those figures matter when planning space and power around the airframe. Choose ER8 for the stated eight-servo arrangement; a smaller control layout may not need its channel count.
RadioMaster RP3 V2 ExpressLRS Receiver
The RadioMaster RP3 V2 stands out for receiver-side features rather than a stated PWM channel count. Antenna diversity, a built-in TCXO, LNA, PA, and WiFi updates through ExpressLRS firmware give it a concrete reason to appeal to demanding FPV applications. Its description also identifies low latency, reliable signal stability, and long-range performance as part of the design brief. The limitation is role: RP3 V2 is an ExpressLRS receiver, not the DJI RC transmitter booster. Its stated working voltage is DC 5V, which is another specific part of the setup's power requirements. It is a focused choice for signal-management features and firmware convenience.
FPV Radio Signal Booster Amplifier Module
The FPV Radio Signal Booster Amplifier Module is built around a DJI RC transmitter rather than an ExpressLRS receiver. Its 2.4G 2W output, 11dB gain, 5-15V operating range, CNC aluminum construction, and heat-dissipation design provide clear reasons to shortlist it when that transmitter path matches the build. The limitation is scope: the module does not take the place of the ER4, ER8, or RP3 V2 as a receiver. Its stated 62 × 32 × 10 mm size and 36g weight exclude the antenna, mount, and power cable, so those measurements describe the module itself rather than a complete accessory setup.
Final recommendation by use case
- Small aircraft, boats, cars, or other compact models: Choose the RadioMaster ER4 ExpressLRS 4-Channel Receiver for its stated four-PWM-channel design and named model types.
- Fixed-wing builds using eight servos: Choose the RadioMaster ER8 ExpressLRS 8 Channel Receiver, whose description directly supports that arrangement.
- FPV builds where antenna diversity and WiFi updates matter: Choose the RadioMaster RP3 V2 ExpressLRS Receiver for those named receiver features.
- A DJI RC transmitter setup: Choose the FPV Radio Signal Booster Amplifier Module, the comparison's part specifically described for that transmitter.
