Solar Car Power Management

Voice Radio Communications

© 1996
Paul Vincent Craven
All Rights Reserved


In order to relay to the driver information about the state of the car, a good voice radio system was needed. For Sunrayce '95 the UMR Solar Car Team used Motorola radios for communication. The antennas sent for the vehicle-mounted rigs were returned twice to the company before the correct ones were finally received. The correct antennas were acquired so close to the race that we didn't have a chance to tune them beforehand. Even afterward we never did manage to get one of them tuned, but the others were eventually tuned on the race route by Scott Ashwell's father.

If an antenna is not properly tuned (cut to the proper length), the radio power is not transmitted, and is instead reflected back to the radio transmitter. The Motorola radio sensed this, and reduced the power transmitted so the radio components would not be damaged. The power that actually managed to be transmitted was so low that we had difficulty talking outside a range of five miles, when we should have had a range of thirty miles.

Besides antenna problems, we lacked enough hand-held radios for good communications. We had two hand-held radios, and could have easily used a couple more. During the race, quite a bit of information needs to be passed over the radio. A lack of practice and formal operating protocol reduced the effectiveness of communication, and caused extra stress among those trying to use the radios.

A good solution would be to require radio operators to get amateur radio licenses. Using amateur radio helps solve many of the above problems. The training that is required to get an amateur radio license would make sure that everyone knew how the radios and antennas work, and how to prevent them from being damaged. As many student amateurs have their own radio, along with members of the Rolla area, it would be easier to get more radios for use during the race. The Motorola Motorolla radios used during the race can be reprogrammed to transmit on amateur bands, preserving UMR's investment in them.

Amateur radio operators have more flexibility with their operating privileges. They can transmit using more power, they have several bands of frequencies on which they can transmit (as opposed to the two frequencies we had for '95), and can set up radio repeaters to extend their range. In addition, using the standard amateur protocol, on-air conversations are more organized and take less time.

Several teams in Sunrayce Sunrayce '95 used amateur radio for communication. The hardest part with using amateur radio is to get everyone to pass the written test. It requires about ten or twenty hours of study to pass for most engineering-type people. If not enough people have the license, then the team is stuck using the business frequencies or CB channels.