Frequently Asked Questions about Sports Timing

Why don’t you use RFID chips for CX races?

While RFID chip timing works great and can be used at a CX race, its just not necessary. Using a good number caller and properly positioned bibs, its possible to produce 100% correct results with CrossMgr even with field sizes of 75 riders or more and fast finishes. Most CX races are selective enough that after the first lap, riders are spread apart, making it easy to call numbers.

The benefit to chip timing a CX race increases as there are more race day walk-ups. As race day registrations exceed 50, it becomes increasingly difficult to enter the walk-ups and also enter bib numbers during the race.  With a chip timed race, the timer can spend more time entering registration data while the RFID system collects chip numbers on each lap.

What is the difference between active and passive RFID tags for racing?

Active RFID tags can be identified by their hard plastic shell. They have a small lithium battery inside that can last up to 5 years or longer. These tags are programmed with a unique number that cannot be changed, so there is additional work required during registration to link the tag numbers to the racer and bib. Active tags offer high reliability and high precision; 1/100 second for J-Chip and 1/1000 second for Race|Result tags.  Active tags have a very high replacement cost of $20 to $60, so they must be collected after events.

Passive tags lack a battery, so they rely on the radio antenna signal to both activate the tag and read the tag data. Passive tags offer lower accuracy, typically 1/10 second, although they may report with 1/100 second precision. For high speed events (above 20mph) a camera is necessary to correctly position finishers when using passive tags. Passive tags have the advantage of low cost (less than $1)  so they do not need to be collected or returned after events. Passive tags are reusable unless damaged by bending or folding.

Where can results be found from completed races?

There are three sites providing long-term hosting for race results produced  by CrossMgr. Results are organized in folders by year and then by event date.

Why isn’t GPS used for timing events?

While GPS data provides positioning data, the resolution of that data can vary between 3 to 30 feet. GPS data is received from satellites orbiting 23,000 miles away, so the signal is very faint when it reaches the ground and can easily be blocked or lost. It can also take up to 30 seconds to receive the complete sequence of data providing the location information. While these capabilities are great for finding a location, they are unsuitable for the high precision and high speeds involved in racing.


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