Transponder timing
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Transponder timing is a technique for measuring performance in athletic events. Prior to the use of this technology, races were either timed by hand (with operators pressing a stop-watch) or using video camera systems.
The first manufacturer to introduce this technology was ChampionChip.TM Subsequently, a number of other manufacturers have offered similar technology. With ChampionChip, a mat energizes a capacitor inside a plastic chip. When the capacitor discharges, a radio signal is broadcast using an antenna within the chip to send a pre-assigned serial number back to the mat. Computers record the exact time that the serial number message was received, so that the athlete's performance can be reported. Other manufacturers include a battery within their plastic casing, so that a small wire can replace the large timing mat. Some manufacturers design their chips to be laced onto a shoe, while others incorporate the chip onto an ankle bracelet.
As events draw very large numbers of participants (in some cases over 60,000 runners), there are delays in participants reaching the start line, which penalize their performance. Some races place timing mats at both the start line and the finish line, which allow the exact net time to be calculated. A controversy has developed as to whether awards in a race should be based on the "gun time" (which ignores any delay at the start) or "net time" (which subtracts the delay.) The USA Track and Field rules have decided that performance is based on "gun time." However, some races use "net time."
When transponder timing was first introduced, the running community hoped for a universal standard, so that timing systems could operated interchangeably, with no overlap in chip serial numbers. However, race management companies have invested in incompatible systems, and individual runners who purchase a chip from one manufacturer, find that the chip is not operable in races that use a competitor's equipment.
