BETAFPV SuperD ELRS Diversity Receiver

The BETAFPV SuperD is an ExpressLRS receiver with true diversity for small FPV drones. It works with an ESP32 and two RF chips and is available for 2.4 GHz and for 915 and 868 MHz. In true diversity two radio chips receive at the same time through two antennas, and the receiver uses the better signal for each packet; that helps when the drone rotates or part of the structure shadows an antenna.

The 2.4 GHz version works with the ESP32-PICO-D4 and two SX1280 or SX1281 chips, the 900 MHz version with two SX1276. The receiver weighs 1.1 g in the 2.4 GHz version and 1.2 g in the 900 MHz version, in each case without antenna. It sends telemetry at 20 dBm (about 100 mW) on 2.4 GHz and at 17 dBm (about 50 mW) on 915 and 868 MHz. Packet rates depend on the band: on 2.4 GHz the modes F1000, F500, D500 and D250 are available, on 900 MHz D50 and 100 Hz Full. These modes denote packet rates and are not end-to-end latency.

In the EU the limit in the 2.4 GHz band without a licence is 100 mW EIRP, which the telemetry uses up. In the 900 MHz range the 868 MHz version is the one to choose for the EU; the 915 MHz version is the FCC variant. Equipment may be operated in the EU only in the approved frequency ranges and power levels. In the open category visual line of sight applies.

When choosing, both antennas should sit far apart and be oriented differently, otherwise diversity brings little. The transmitter module must work in the same band and with a matching ExpressLRS version. The two antenna connectors and the solder pads are the wear points in crashes.