Review: RadioMaster RP4TD ExpressLRS Receiver – True Diversity Supports ELRS Gemini Mode

by Oscar
Radiomaster Rp4td Diversity Expresslrs Elrs Receiver Rx

The buzz around ExpressLRS Gemini Mode is undeniable, yet there’s a lack of true diversity receivers on the market that support this awesome feature. Enter the RadioMaster RP4TD – marking a significant upgrade from its predecessor, the RP3, which only offered antenna diversity. Let’s dive in to see what it offers.

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Learn more about ExpressLRS in our comprehensive tutorial: https://oscarliang.com/setup-expresslrs-2-4ghz/

What’s Gemini Mode? https://oscarliang.com/expresslrs-gemini/

Where to Buy?

Get the RP4TD Receiver from these vendors:

The package includes a set of silicone wires for connecting to the flight controller, and three pieces of clear heat shrink, enhancing the durability of the setup.

Radiomaster Rp4td Diversity Expresslrs Elrs Receiver Rx Unbox Accessories

Technical Specifications

  • MCU: ESP32
  • RF Chip: Dual SX1281
  • Antenna: Dual 65mm 2.4GHz T Antennas
  • Frequency Range: 2.4GHz
  • Maximum Refresh Rate: 500Hz / F1000Hz
  • Telemetry RF Power: Max 100mW (x2)
  • Working Voltage: DC 4.5-12.0V
  • Weight: 1.4g (excluding antennas)
  • Dimensions: 23.7×16.3×4.0mm
  • Pre-installed Firmware: ExpressLRS V3.3.0
  • Firmware Target: RadioMaster RP4TD 2400 RX
  • Bus Interface: CRSF
  • Extend Interface: UART

The standout feature of the RP4TD is its two separate SX1281 RF chips and TCXO (Temperature Compensated Crystal Oscillators). This design means the receiver is better equipped to handle a wide range of temperatures and challenging environments. With dual RF chips, the RP4TD offers two telemetry outputs at 100mW each, a significant upgrade for long range flying. For those looking to push the limits of 2.4GHz FPV flying, this receiver seems like an ideal choice.

Build Quality

The receiver itself is compact and well-built.

The top side features a boot button and two U.FL connectors for the antennas. The four soldering pads are accessible on both sides of the receiver with clear labels: 5V, GND, RX and TX.

Radiomaster Rp4td Diversity Expresslrs Elrs Receiver Rx Closeup Pcb Top

Radiomaster Rp4td Diversity Expresslrs Elrs Receiver Rx Closeup Pcb Bottom

Although the RP4TD is notably larger than single-antenna EP1 receivers due to its dual RF chains, the design remains impressively compact.

Radiomaster Rp4td Diversity Expresslrs Elrs Receiver Rx Size Compare Ep1

However, the inclusion of longer antennas could have enhanced its appeal for larger builds, such as 7″ or 10″ drones. Nonetheless, extended antenna wires are readily available for those in need:

95mm / 120mm / 240mm antenna:

Installation

Installing the RP4TD is as straightforward as any ExpressLRS receiver. The key is to ensure optimal antenna placement. To ensure the best reception, positioning the antennas to avoid getting blocked simultaneous by any part of the quadcopter is crucial. This separation is vital for maintaining a consistent and reliable connection.

Conclusion: Is the RP4TD Right for You?

Radiomaster Rp4td Diversity Expresslrs Elrs Receiver Rx

Note that true diversity doesn’t necessary increase range but intended to boosts reliability and link quality, particularly with Gemini mode enabled.

The RadioMaster RP4TD Diversity ELRS Receiver is a significant upgrade for FPV pilots seeking the utmost in reliability and performance. Its dual-chip design and robust build make it a top choice for demanding flight conditions.

Get the RP4TD Receiver from these vendors:

For those building larger drones, consider getting some longer antennas for the best setup. For those who push their FPV flying to the extremes, the RP4TD is a worthy investment, ensuring that your drone remains in constant, reliable communication with your transmitter.

95mm / 120mm / 240mm antenna:

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5 comments

Bruce manning 2nd April 2024 - 4:02 pm

Hi what the difference between radiomaster r81 and rp4td

Reply
Oscar 2nd April 2024 - 11:46 pm

R81 uses Frsky protocol while the RP4TD uses ExpressLRS.

Reply
Beast 29th March 2024 - 12:47 pm

How to solder RP4TD with regular servo cable plug i mean there would three wire one goes for(+) and one goes for(-) and remaining one to RX or TX? I am doing it so to connect it to my Hex orange cube plus.
thank you

Reply
Greg 11th February 2024 - 5:53 am

So how does that receiver work without a gemini module? Does it just use one antenna or does it use antenna diversity?

Reply
Oscar 12th February 2024 - 3:37 pm

Yes, it works with non-gemini transmitter modules.

Reply