For now UKHASnet is based in the 868 MHz band, specifically in the 25KHz channel on 869.5 MHz. This is due to the 100mW License-Exempt RF output permissible both terrestrial and airborne at a 10% duty cycle (per device) in the UK.
If you are located in another country, please check our own regulations.
The HopeRF RFM69HW is the official replacement for the EOL RFM22B.
Manufacturer Page: RFM69HW
The 868MHz *HW* version of this module is capable of 100mW with a power supply of 2.4V - 3.6V. It is also capable of 50mW down to 1.8V.
Currently this module is not commonly available for sale, especially not in the UK. The best place to source this module in Europe appears to be from http://webshop.ideetron.nl/RFM69HW. Do add to this if you find anywhere else.
The RFM69W-868S2 is now stocked by Hab Supplies. This is the 13dBm (20mW) version but this should be adequate for short range nodes.
The HopeRF RFM22B was the first radio module to be used, due to it's availability from several UK electronics suppliers, and existing experience of it within the developing group.
The 868MHz version of this module is capable of 100mW transmit power with a power supply of 1.8 - 3.6V.
Several people have encountered reliability issues with this module, and that combined with it currently being EOL, means that we have been looking for a replacement.
These ICs are commonly used in modules such as the RFBee.
James Coxon is currently using an alternative network based off of these transceivers. However they do not appear to inter-operate easily with the RFM– series.