If you are looking for a professional, high datarate, long range ardupilot compatible telemetry modem then the RFD868x is what you have been looking for. The RFD868x modem runs the same open source Sik firmware as used on the 3DR telemetry modems, however, the hardware on the 868x has been designed to offer some significant range and performance improvements over the standard 3DR telemetry kits.

These modems feature a powerful ARM 32bit processor allowing for an air data rate of up to 500kbit/s, with full support for RC PPM pass through. Designed for professional users in mind the modems also feature fully ESC protected and filtered design, allowing for ranges of greater than 40Km with high gain tracking antennas. So if you are looking for a professional level telemetry link and cheaper 433mhz unmanned telemetry kit doesn’t cut it, then the RFdesign 868x Telemetry kit is what you need.

RFD868x New Features

• New Processor, ARM 32 bit core.
• Air data rate: 500kbit/s.
• AES Hardware accelerated encryption. *Fully working*
• RC PPM Passthrough with telemetry at the same time.
• Fully ESD protected + filtered – Every IO port is protected and filtered.
• Original SiK point to point, multipoint firmware implemented.
• Asynchronous multipoint firmware, *Beta release*

Key Features

• Long range >40km depending on antennas and GCS setup *80km demonstrated by Edge Research labs on a balloon !, 57km in India, on Dipoles.
• 2 x RP-SMA RF connectors, diversity switched.
• 1 Watt (+30dBm) transmit power.
• Transmit low pass filter.
• > 20dB Low noise amplifier, high IP3.
• RX SAW filter.
• All I/O ESD protected and filtered.
• Re implemented SiK and Multipoint SiK firmware, field upgradeable, easy to configure.
• Small, light weight.
• Compatible with 3DR / Hope-RF radio modules.
• License free use in Australia, Canada, USA, NZ

 Interfaces

• RF : 2 x RP-SMA connectors
• Serial: Logic level TTL (+3.3v)
• Power: +5v, ~800mA max peak (at maximum transmit power)
• GPIO: 6 General purpose IO (Digital, ADC, PWM capable).

Specifications

• Frequency Range:  868-869 MHz
• Output Power: 1W (+30dBm), controllable in 1dB steps ( +/- 1dB @=20dBm typical )
• Air Data transfer rates: 4, 8, 16, 19, 24, 32, 48, 64, 96, 128, 192 and 250, 500 kbit/sec ( User selectable, 64k default )
• UART data transfer rates: 9600, 19200, 38400, 57600, 115200, 400k, 921k baud  ( User selectable, 57600 default )
• Output Power: 1W (+30dBm)
• Receive Sensitivity: >121 dBm at low data rates, high data rates (TBA)
• Size: 30 mm (wide) x 57 mm (long) x 12.8 mm (thick) – Including RF Shield, Heatsink and connector extremeties
• Weight: 14.5g
• Mounting: 3 x M2.5 screws, 3 x header pin solder points
• Power Supply: +5 V nominal, (+3.5 V min, +5.5 V max), ~800 mA peak at maximum power
• Temp. Range: -40 to +85 deg C, tested operational from -73 to +123 deg C.

Software / GCS Support

The software solution is an open source development called “SiK”.  It has been re implemented to suit the new processor architecture available on the 32bit ARM processor core.  A boot loader and interface is available for further development and field upgrade of the modem firmware via the serial port.

Most parameters are configurable via AT commands, Eg. baud rate (air/uart), frequency band, power levels.

Integrated support for configuring the RFD900 radios is supported by APM Planner.

The default settings are at 57600 baud, N, 8, 1, and 64k air data rate.

The RFD868/900x manual is here: RFD900x Manual

The RFD868/900x SiK software manual is here : RFD900x Peer-to-peer Manual

Software features include:

• Frequency hopping spread spectrum (FHSS)
• Transparent serial link
• Point to Point, or Multipoint networking
• Configuration by simple AT commands for local radio, RT commands for remote radio
• User configurable serial data rates and air datarates
• Error correction routines, Mavlink protocol framing (user selectable)
• Mavlink radio status reporting (Local RSSI, Remote RSSI, Local Noise, Remote Noise)
• Automatic antenna diversity switching on a packet basis in realtime
• Automatic duty cycle throttling based on radio temperature to avoid overheating

Compliance

The RFD868 is designed to be compliant with the following standards:

• FCC Part 15.247 (Frequency hopping and digitally modulated intentional radiators)
• AS/NZS 4268:2012 (Radio equipment and systems – short range devices)

The modem is designed for system integrators who will integrate the modem into their own projects and product prototypes.  The user is responsible for compliance with local regulations for radio transmitters.