ExpressLRS is ridiculously great for long range, but diversity receivers can take it to the next level! In this post I will feature a few popular and latest ELRS diversity RX options and explain their features.
New to ExpressLRS? Check out my complete guide to ELRS 2.4GHz.
Table of Contents
Why Diversity Receivers?
If you want to get the best possible range and signal, and do not mind paying a few more dollars and adding a couple more grams to your model, ExpressLRS diversity receiver is the way to go.
Most people probably won’t benefit a lot from diversity receivers if the maximum range has not yet been reached on the single antenna receiver. But for those who fly long range, diversity receivers are great on quads as well as planes. Anyway, these diversity receivers are so light, they won’t impact flight performance much even on micro drones either, so why not?
Why TCXO?
TCXO stands for temperature compensated crystal oscillator.
All transmitters and receivers works on a certain frequency. Both TX and RX must operate at the same frequency to maintain a strong link. The precision of the frequency depends on the crystal oscillator.
Older ExpressLRS hardware used low quality crystal oscillators which results in high error, which is even worse in extreme temperature. TCXO is much more robust in this regard as it ensures your receiver has a stronger link with the transmitter, even in extreme high or low temperature.
BetaFPV SuperD
Where to Buy?
Get the BetaFPV SuperD Diversity Receiver here:
- BetaFPV: https://oscarliang.com/product-g4r7
- AliExpress: https://s.click.aliexpress.com/e/_DDifVqr
Specs and Features
- ExpressLRS 2.4GHz
- MCU: ESP32 PICO D4
- RF Chip: SX1280 (SX1281) x2
- Antenna Connectors: IPEX MHF 1 (U.FL)
- 2x T Dipole Antennas, wire length 70mm
- Telemetry Power: 20dBm (100mW)
- Maximum packet rate: 500Hz / F1000Hz
- Minimum packet rate: 25Hz
- Input Voltage: 5V DC
- PCB Size: 22mm*14mm*3mm
- Weight: 1.1g excluding antenna, 3.4g including both antennas
- FW Target: BetaFPV 2.4GHz => SuperD 2.4GHz RX
It’s almost twice as big as the BetaFPV Lite receivers. It has two dipole antennas, BetaFPV recommends to place both antennas vertically and as far apart as possible to achieve ideal results. However further testing will be required to verify this.
The BetaFPV SuperD receiver uses “true diversity”, meaning there are basically two separate receivers onboard working simultaneously. They share the same processor and crystal oscillator, but each receiver has its own RF chips and antenna, and it will simply pick the stronger signal.
It comes with ExpressLRS V3.0.0 firmware pre-installed. Firmware target is already available in the configurator for flashing: BetaFPV SuperD 2.4GHz RX.
BetaFPV boasts a high-quality TCXO (temperature compensated crystal oscillator), which offers far more accurate frequency and stable signal even in extreme temperatures for long range flying. The frequency of the crystal oscillator shifts due to change in temperature, meaning your range can suffer when it’s either too cold or too warm. This TCXO can give you more consistent performance regardless the temperature outside.
The status indicator is a single RGB LED. The packet rate is shown by using different colour on a rainbow spectrum, which is really clever and unique. I have not seen this on any other products before.
Radiomaster RP3
Where to Buy?
Get the Radiomaster RP3 from:
- Radiomaster: https://oscarliang.com/product-6hyt
- RDQ: https://oscarliang.com/product-lbey
- AliExpress: https://s.click.aliexpress.com/e/_DF9BiCJ
Specs and Features
- ExpressLRS 2.4GHz
- MCU: ESP8285
- RF Chip: SX1280IMLTRT
- Onboard LNA/PA chip
- Telemetry RF power: up to 100mW
- Antenna Connector: IPEX MHF 1 (U.FL)
- T Dipole Antenna x2, wire length 65mm
- Maximum packet rate: 500Hz / F1000Hz
- Minimum packet rate: 25Hz
- Input voltage: 5V
- Dimension: 22mm*13mm*4mm
- Weight:
4.6g4.8g (Including two antenna) - FW Target: RadioMaster 2.4GHz => RP3 Diversity 2400 RX
It’s about twice as big as the RP1 and RP2 receivers.
Note that the RP3 has antenna diversity, not receiver diversity. It has two antennas, but only one RF receiver chain instead of two. It’s a compromise between performance and cost as it uses fewer chips than the “real diversity” receivers. Still, antenna diversity offers improved signal stability and range over the cheaper single antenna designs.
It has LDA (low noise amplifier) and PA (power amplifier) chip which improves signal stability and telemetry range. Telemetry requires the receiver to transmit signal back to the radio, and the power amplifier can boost telemetry signal.
The RP3 has ELRS V3.0 pre-installed, firmware is already available in the configurator for flashing, target is Radiomaster RP3 Diversity 2400 RX.
There’s a mistake in the manual regarding telemetry output power, it says 250mW but it should be 100mw. This has been confirmed with Radiomaster.
Happymodel TCXO EP1 Dual
Happymodel has released a new ELRS receiver lineup with TCXO (temperature compensated crystals) built-in, EP1, EP2 and EP1 Dual.
I will be doing a comparison when this receiver comes in. It has the same multicolored LED for status indication like the BetaFPV SuperD.
Specs:
- ESP32 PICO D4, dual SX1280(SX1281)
- Antenna connector: IPEX MHF 1/U.FL
- RF Frequency: 2.4GHz (2400~2480MHz)
- Telemetry power: >19dbm
- Receiver protocol: CRSF
- Input voltage: +5V DC @ “+” pad
- PCB size: 19mm x 14mm
- Weight: 1g (excluding antenna)
- Built-in a TCXO (temperature compensated crystal oscillator)
- Firmware: HappyModel EP1 Dual 2400 RX (starting from ExpressLRS V3.0)
31 comments
Dear oscar, already thanks for your knowledge, got a question..
My happymodel ep1 tcxo small T antenna is broken, can i replace it without problems for the long one wich came in the box?
New in this, first build..
Greetings from the netherlands, Danny
Yes, you can just use the spare antenna.
Hey Oscar, Thanks for the all the great information! Would a pair of shorter 2.4ghz antenna work on the rp3? Something linear without the T? I am looking to save some space, and I only need minimal range. Thanks for any insight you can provide! -JB
Sure, it should work but it might impact performance. There’s a compromise to be made when saving weight/space.
Hi:
I need to know, where is located the “BOOT MODE BUTTON”. My Rx RP3 ExpressLRS 2.4ghz Nano Receiver is Bricked.
I don’t see any information in the manual. Will you have a video or connection diagram?
Thank You
There’s a button on the RP3 (on the side of the antenna UFL connectors), do you not see it?
Press and hold it while powering on the receiver should enter flashing mode.
wish that worked mine has come bricked, just now got around to building the quad i purchased the rx for a cool 5 months ago, it never went into bind mode. frustrating,, ill try the button again
Hi Oscar,
With the Radiomaster RP3, would there be concerns/issues while using it with one default 79mm antenna and a 220mm TBS immortal T as they vary in lengths , considering you pointed out antenna diversity?
Was thinking of buying the radiomaster receiver but then I saw it didn’t have true diversity. Does the receiver still switch to the antenna that’s the strongest? How is receiver diversity and antenna diversity different in the way they switch between the two antennas?
ExpressLRS receivers with a single antenna are probably enough for most people’s need. Regardless, either Antenna diversity or true diversity, will be better than single antenna RX for sure if you have the budget for it. I’d get True Diversity receiver if possible, especially for Gemini mode, you definitely want to get True Diversity receiver.
Radiomaster RP3 VS Happymodel TCXO EP1 Dual? wich 1 is better? i know one is TrueDiversity but RP3 has LNA/PA chip , what do you think?
Just based on design, the Happymodel has two receiver chains so might be better. But I haven’t actually tested the hardware so can’t comment on its build quality and actual performance. Honestly I don’t think you can go wrong with either one.
Thanks a lot for your feedback, i currently have RP3 and very happy with it so far. just made a small tweak on source code to send signal to RSSI1 and RSSI2 :) But im curious about Happymodel TCXO :)
Thanks mate
“Hello, I have a problem as I am new to this hobby. How do I connect the connectors from the Betafpv SuperD ELRS dual antenna receiver to the FC Mamba F405 mk2 connectors? Please provide a prompt response and thank you in advance. Best regards.”
Find a spare UART on the flight controller (which has two pads, TX and RX), and connect TX pad on the Receiver to the RX pad on the FC, and RX pad on the receiver to the TX pad on the FC. Then connect 5V to 5V, and GND to GND. See this wiring diagram for reference, different flight controller but the idea is the same: https://oscarliang.com/wp-content/uploads/2022/11/how-to-build-fpv-drone-2023-wiring-diagram-analog.jpg
I understand where to connect the 5V and GND, but I’m not sure about the TX and RX ports. Prior to your message, I had (or still have) connected the RX on the receiver to TX1 on the flight controller and the TX on the receiver to SBUS. Is that correct? Because the flight controller I have doesn’t have RX and TX ports, but instead has TX3, TX6, RX3, and RX6 ports. If you have time, please review the documentation for my Mamba F405 mk2 flight controller and let me know. Thank you and best regards.
RX and TX are the same thing as TX3, RX3, the number just indicate which UART it is.
If you want to use UART 1 (because you said you are connecting to TX1), you should find where RX1 is and connect it to the TX pin on the receiver. Do not use SBUS as it has an inverter and it wont work. Or you can use any other spare UART like TX3/RX3 or TX6/RX6 as you mentioned.
If you have time, I would like to ask you to look at the documentation for FC Mamba F405 mk2 and show me exactly (can also be via image) how to connect it. The issue is that my FC does not have a TX and RX connector, but it has TX3, TX6, RX3, and RX6 connectors, and I am not sure if they are the same. Additionally, I am not sure if I can connect anything to SBUS since I will be using the ELRS protocol with their receiver and transmitter.
he told you already use tx3 rx3 or tx6 rx6 dont use sbus or it wont work
I can also give you an opinion regarding your VTX. I have the Eachine TS5828L 600mW 5.8G 40CH. The problem is that in the software it says that I don’t have the VTX connected correctly, but I checked if the camera works and it did. Now I’m not sure if I connected it correctly. I connected the voltage to VCC, then connected two GNDs to GND (each on its own connector) on the FC, and connected the video to VID on the FC (I don’t need the audio connectors).
Hello !
I can’t figure out how many channels I will have with one of these receivers and a Zorro ELRS for example.
Can someone explain to me please ?
ELRS can support up to 12 channels. The first 4 are your controls from your sticks (roll, pitch, throttle, and yaw), and then you get 8 aux channels where aux 1 (channel 5) must be your arm/disarm channel. Hope this helps!
I arm with my sticks. I just assigned channel 6 to channel 5, so channel 5 now has full resolution (I only have a 5 channel receiver, so don’t need ch 6). I think ELRS 3.0 might have changed this, but I dunno, as I still have it set to using channel 6 on channel 5. I’ve been trying to find some videos of this SuperD in action, though, as I would like to get it, since I have already had failsafes due to the way I have my single antenna routed.
Hello !
I can’t figure out how many channels I will have with one of these receivers and a Zorro ELRS for example.
Can someone explain to me please!
Ty
can Radiomaster RP3 rollback firmware 2.X ? I have no plan to update ELRS 3.0 for all my quad.
check in the configurator and if you can find the receiver you want to flash in firmware 2.X. If not then it’s not possible.
Is the conclusion that the SuperD is better and longer range due to true diversity and slightly lower weight?
Also, for the RP3, on the radiomaster and RDQ sites it says max telememetry power is 100 mW, not 250 mW, do you know which is correct?
There’s a mistake in the manual regarding telemetry output power, it says 250mW but it should be 100mw. This has been confirmed with Radiomaster.
> it’s recommended to place both antennas vertically and as far apart as possible to achieve ideal results.
What’s the logic behind it? People used to recommend doing vertical+horizontal with diversity.
This is just the manufacturer’s recommendation.
Why not the EP1 Dual?