ACCURACY REQUIREMENTS AND EQUIPMENT CHOICE

The CC737, CT200 and CT600 timers always time with .001 second resolution, however photocells and a wire connection to the other end of the course are needed to actually achieve that accuracy. Fortunately in short races where the errors are more important it is also easier to string wire and operate electronically. For races where all the contestants start at the same time, the timer can often be started at the start and carried to the finish to record the finish times. In long races where it is difficult to connect with wire it may also be that an error of a few hundredths or tenths of a second is not important, so the methods of capturing times can be varied. If times are going to be reported only to the nearest second there are a number of methods to choose from to achieve that accuracy.

Starting additional Timers
Once the starting time has been captured by a Timer at the start, other Timers can be started quite accurately by what is called "hacking". Both Chronomix Timers and Displays can be preset to an exact time and then started when the race time reaches the hack time. By watching the Timer or by listening to someone report the time even over a radio or telephone, the second Timing unit can be started within a few tenths of a second of the first timer. For most longer races this will provide acceptable accuracy so that separate timers can be used at the start and finish of the race.

Timing Methods and Accuracy Considerations
Timing with a manual timing cord, (a hand held switch) introduces errors of approximately .02 to .03 seconds and the error may be fast or slow. This is due to human reaction time and varies with the experience of the timer. For long distances it is often impractical to connect the start and finish with wire for electronic timing so it becomes important to consider the desired results when selecting a timing set up. If times taken to the nearest second will be satisfactory, a verbal relay can provide the needed accuracy. The Timing equipment is positioned at one end of the course and the starts or finishes are called in over a radio or telephone from the other end of the course. The operator at the Timer enters the time and usually the competitor number. Calling starts or finishes over a radio or telephone will delay all times by .4 to .5 seconds. As this delay is relatively constant it can be either ignored or if desired an adjustment can be made to all times to bring them closer to the true elapsed time value.

True Elapsed Time
Keep in mind that if the exact position of the start and finish lines vary a few inches or feet from day to day, or the timing personnel change, etc., times may not be truly comparable from session to session and the true elapsed time becomes less important. This writing assumes that the goal is usually to establish the correct finish order of the contestants for the current session, and that record setting accuracy requiring the use of photocells and many other constant conditions is not contemplated.
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