The RFM69HCW module is capable of transmitting at up to 100mW and up to 300kbps. These values can be adjusted to suit your specific application. For instance, you can increase the transmit power and reduce the data rate to maximize range, or decrease both for short-range sensor networks that consume minimal battery power. With simple wire antennas and at full power, the module can transmit messages across a large office building, through numerous internal walls. In open air, the range can exceed 500 meters. More complex antennas and modulation schemes can even enable transmission from space to the ground.
The RFM69HCW uses an SPI (Serial Peripheral Interface) for communication with a host microcontroller. It supports up to 256 networks of 255 nodes per network, features AES encryption for data privacy, and transmits data packets up to 66 bytes long. Sparkfun offers two versions of the RFM69HCW: the 915MHz version and a 434MHz version. The 915MHz version is intended for use in the Americas, while the 434MHz version is for use in Europe, Asia and Africa.
The RFM69HCW module boasts a range of features. It has a power output capability of +20 dBm - 100 mW, high sensitivity down to -120 dBm at 1.2 kbps, and high selectivity with a 16-tap FIR Channel Filter. Its front end is bullet-proof with IIP3 = -18 dBm, IIP2 = +35 dBm,80 dB Blocking Immunity, and no Image Frequency response. The module also has low current: Rx = 16 mA, 100nA register retention, programmable Pout: -18 to +20 dBm in 1dB steps, and constant RF performance over the voltage range of the module. It supports FSK Bit rates up to 300 kb/s, has a fully integrated synthesizer with a resolution of 61 Hz, and supports FSK, GFSK, MSK, GMSK and OOK modulations. Other features include a built-in Bit Synchronizer performing Clock Recovery, Incoming Sync Word Recognition, 115 dB+ Dynamic Range RSSI, Automatic RF Sense with ultra-fast AFC, a packet engine with CRC-16, AES-128, 66-byte FIFO, and a built-in temperature sensor.