On a rally, when the drivers leave the service park for the stage loops, it is imperative that they are able to communicate with their engineers and key team personnel at all times.
In order to facilitate this, the team incorporates a raft of communications equipment into each Impreza WRC2007, including VHF radio, mobile phones and satellite phones, and the engineers share the same technology back in the service park.
Team coordinator Ken Rees is the man in charge of VHF (Very High Frequency) radio communication with the drivers. He uses the radio to transmit non-confidential information to each rally car such as split times, event information and service times. The drivers will report their stage times to Ken when they finish each test, or communicate any problems.
Each WRC team is allocated a specific radio frequency for each rally by the FIA, but as each is made public to all teams, the system is certainly not confidential. Ordinarily the radios have a 5-6 mile line-of-sight range but this is increased by the use of a repeater unit carried in a plane above the rally, bouncing the signal over twice the distance.
This system is also used to send text messages of up to 14 characters from a laptop computer in the service park to a display screen in the car, located in the co-driver's footwell. Radio silence is observed once a stage has started, but Ken uses the data system to keep the co-drivers updated with competitors' live split times.
"The confidential nature of most communication between drivers and their engineers typically means we use a standard tri-band mobile phone, but this can be limited by the quality of the network coverage, especially in the more remote areas," explains Nick Chalkley, the team's senior electrical technician.
"On rallies such as Argentina or Japan, signal can be very poor, in which case a satellite phone will be used instead," he points out.
"With a great deal of background noise in service areas, we connect the engineers' phones to noise cancelling headsets, each complete with a microphone. The drivers use the same setup in the car, and it makes communication far more efficient. A signal splitter in the service area allows technicians or management to plug in to the conversation making it possible to hold conference calls with the right people as necessary," Chalkey elaborates.
Having open lines of communication will always be an important advantage; the Subaru engineers therefore do their best to make sure the signals remain strong on each event.
