The system combines analogue HF radio with a satellite link to allow effective conference calling between the UK base and the Ice Team. Each member wears a duplex radio that allows simultaneous transmission and reception by operating on split frequencies. All transmissions on the first frequency are picked up by a radio repeater on Pen’s sledge and retransmitted on the second frequency. By routing all speech communication through the sledge, the two way speech on the satellite link can be mixed in so that anything said by an ice team member is heard back at the UK base and anything said in the UK can be heard by all the ice team.

Pen’s sledge also contains a speech archive system. This has two uses. Firstly, to provide a memo facility for Pen so that all ice observations and measurements can be captured off the radio link for onward transmission to the UK each night. Secondly, it provides a long term archive of all speech communication during the expedition. The sledge radio repeater and speech archive are known as the HUB.

The duplex radios worn by the ice team members are carried in a pouch in the small of the back and worn underneath the outer garment. This helps maintain a reasonable operating temperature. Internal batteries give 100 hours life and will be replaced at intervals. User controls are kept to an absolute minimum and are located on a small box worn on the sledge harness straps. One button gives the usual PTT (push-to-talk) function and also allows entry to a hands-free VOX (voice activated transmission) mode. The second button enables the MEMO facility with a feature to allow replay of the last three memos as an integrity check. A throat microphone and single earpiece (to allow normal ice-sounds to still be heard) provide the audio link with cabling being routed inside the outer garment.

Satellite calls to the UK base are initiated via a button on the HUB, a switch allowing a selection of called number. Once the call is established, a conversation can take place via the radio link whilst on the move or if the highest quality speech is needed (e.g. during an interview) then a headset can be plugged into the HUB. Incoming calls are not allowed as this would imply always keeping the satellite phone always powered.

The design of this 3-way communication system will allow conference calls to be established and live commentaries can be fed through the website. Overall this will allow a far more intimate connection with the explorers for those following from the comfort of their homes and offices.