RFDesign RFD 868x Modem
by RFDesign

RFDesign RFD 868x Modem

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 firmware implemented.
• Note: Currently due to the bandwidth limitations of the 868 modems Asynchronous Mesh and Multipoint Firmware are not officially supported for the 868X modems and correct operation of this code cannot be guaranteed

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 firmware, field upgradeable, easy to configure.
• Small, light weight.
• Note: Not compatible with older modems

 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 capable). 

Specifications:

• Frequency Range:  865-870 MHz
• Output Power: 1W (+30dBm), controllable in 1dB steps ( +/- 1dB @=20dBm typical)
• Air Data transfer rates: 12, 56, 64, 100, 125, 200, 224, 500 and 750 kbit/sec (User settable, 64kbit default)*
• UART data transfer rates: 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, 1M baud (User settable, 57600 default)*
  

  *note these values are correct as of version 3.16 SiK firmware

• Output Power: 1W (+30dBm)
• Receive Sensitivity: >111 dBm at 12kbps, 105 at 64 kbps and 98 at 200kbps
• 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.
• The RFD868x will not communicate with the RFD868x-EU modem unless the standard RFD868x is configured to the same frequency as the EU modem.

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
• Configuration by simple AT commands for local radio, RT commands for remote radio
• User configurable serial data rates and air datarates
• 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