Accuracy (Excluding Stored Passings)

When a transponder passes over a loop the transponder will receive multiple signals (hits) from the loop, the internal algorithm of the transponder then calculates the time which should be transmitted to the timing system, this time should be when the transponder passes the center line of the loop. 

V3 Active transponders contain a new advanced algorithm for calculating exact passing time with the highest repeatable accuracy of any transponder, this accuracy is not so greatly impacted by variables in loop setup (width / power) or passing speed. V3 Transponders (excluding ActivePro V3 Performance) require a minimum of 2 hits from the loop to be considered a valid passing. The maximum number of hits reported by a V3 Transponder for a regular passing is 99 hits.

*Only applicable when using Ubidium

Accuracy: The repeatable accuracy of the passing time calculated by the transponder, if 2 transponders are recorded with a difference greater than the accuracy then the order of passings will be correct. 

Reaction Time: The maximum time for which the transponder will wait for a stronger loop signal before transmitting its passing. Lower reaction time = faster transmission of data. 

Internal Resolution: The resolution of the transponder's internal time base. 

Passing Resolution: The precision to which a passing is calculated. 

Store Mode

Store mode allows the transponder to record the time at which it passes a loop in the internal memory, this is actually achieved by calculating the time since the stored passing and as such relies on the transponder's internal time base. 

ActivePro (+Performance) / MotorKart V3

The internal time base of every V3 transponder is calibrated during production to provide a clock accuracy of +/- 10ppm. 

Additionally the stored passing times are also calculated using a temperature compensation, as particularly at low temperatures there can be greater drift. The optimum working temperature is 25°C.

The result is a time with a maximum drift of just 0.036s per hour, across the transponder's working temperature range.

ActivePro / MotorKart V2

The internal time base of the transponder is dependent on the calibration at the time of manufacturing the internal oscillator. No temperature compensation is applied to the calculated times. 

Continuous / Exit Passing

When held over a loop for a prolonged period of time V3 transponders generate additional continuous passings and an exit passing with greater precision than previous versions. 

Continuous passings will be sent every 5s after the initial passing is generated by a transponder. These can be identified by a hit count of 254. 

Exit passings are sent when the transponder leaves the field of a loop after being within the field for a minimum of 3 seconds. The Exit passing is identified by a hit count of 255. 

Exit passings are generated with accuracy according to the type of transponder.

ActivePro V3 Performance: 0.02s
ActivePro V3: 0.1s
ActiveBasic / MotorKart V3: 0.2s

Sensitivity

V3

To ensure maximum accuracy of passings the sensitivity of transponders is adapted during a passing. 

Whilst awaiting activation from a loop the sensitivity of transponders is equal to Active V2 transponders. After the first loop packet is received the sensitivity will be increased, this effectively increases the detection range  / height of the transponder, which will then continue to observe the loop packets as normal.

Once the transponder leaves the field of the loop the sensitivity will again drop to normal levels.  

This increase in sensitivity helps eliminate a passing being generated too early, particularly when worn on the ankle as the transponder move through the field of the loop. 

The impact of this can be seen when testing loop detection height - once a transponder is activated by a loop it must be moved much further away to leave the field of the loop. The additional range can be as much as 50cm. 

Overlapping Loops

It is always advised to maintain a minimum distance between 2 loops equivalent to maximum speed in km/h divided by 10, in meters. e.g. 60km/h = 6m

V3

Active V3 transponders can internally handle loop data from 2 separate overlapping loops. Whilst observing 2 loops the transponder will choose when to switch from the first to second loop and a passing will be generated for both loops, the accuracy however may be impacted when loop fields are overlapping. 

V2

Active V2 transponders cannot handle overlapping loops and such instances can result in loss of data from one or both loops.