During their time on the ice, the team will be able to communicate between themselves
and the UK HQ, thanks to a 3-Way Person-to-Person communications system, developed
especially for the Catlin Arctic Survey.
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.