BETAFPV ELRS Nano Receiver 915MHz/868MHz

The BETAFPV ELRS Nano Receiver 915MHz/868MHz is an ExpressLRS receiver in the sub-GHz range (below 1 GHz) for small FPV drones, available in versions of 915 MHz for the FCC area and 868 MHz for the EU. It works with an ExpressLRS transmitter module in the same band. Low frequencies penetrate obstacles better than 2.4 GHz and carry further at the same power, which is why sub-GHz receivers are chosen for long-range flights.

The receiver weighs 0.7 g. The packet rate is 200 Hz at most, which gives 5 ms between two packets by calculation; in the 2.4 GHz band ExpressLRS reaches clearly higher rates. This rate is a packet interval and not end-to-end latency. It shows the trade-off of the sub-GHz band: fewer packets per second in return for more range and penetration. In return sub-GHz links need longer antennas and offer fewer packets for telemetry data.

The 915 MHz version is the FCC variant and is not intended for use in the EU; in the EU the 868 MHz version is the one to choose, whose band has its own power and duty-cycle limits. 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, and long ranges are no selection criterion there, but they are for operations in the specific category.

When choosing, the band variant and the matching antenna come first: sub-GHz antennas are longer than 2.4 GHz antennas, and an antenna that is too short or badly routed costs range. The transmitter module must work in the same band and carry a matching ExpressLRS version. At 0.7 g the solder pads and antenna connector are the wear points.