It can happen that an Active Transponder will generate a passing with an invalid Channel ID / Loop ID, these are most commonly received as stored passings due to the cause for triggering them. Normally these invalid passings have just a single hit and there are 3 possible causes that we have identified:

Corrupt Data From Loop

When on the edges of the loop field the data packet received by the transponder can be corrupted, this results in the Transponder storing a passing with the incorrect Channel / Loop ID and a single hit. This was fixed in V2 transponders from November 2017, the new configuration requires 2 hits for a valid passing.

Participants Standing on Loops (Swim Starts)

The most common time this happens is during rolling swim starts when participants are stood directly on or near the loop for long periods of time. This results in similar corrupt data packets as above which would normally be ignored but due to the rapid consecutive detections the transponder may incorrectly store an invalid passing. This can happen to any ActiveTransponder

External Interference

The 125kHz channel is not unique to RACE RESULT transponders, and transponders may sometimes be activated by external electrical interference such as power cables and store a passing, which could be from the day before. This rarely happens to new V2 transponders due to the new configuration but can happen to any transponder if the interference is strong enough to cause multiple hits.

Solutions

If you have older ActivePro V1 Transponders we offer a trade-in program to upgrade to V2 transponders which eliminate most of the invalid passings. 

Your decoder has an option to discard all stored passings, if you are not working with stored passings then you could choose to discard stored passings, as these issues are always reported as stored passings then they will be discarded. Warning: You may lose valid detections which have been stored by the transponder which could not be transmitted directly to the Active Extension or Loop Box.

In firmware version 2.26 we introduced an option to discard all passings below X number of hits. We have found that nearly all invalid passings are reported with a single hit, so setting this to discard all passings below 2 hits can solve this, you can also set the value higher if you are seeing lots of invalid passings with more than 1 hit. WARNING: This will discard ALL passings with less than X hits, so if you do have valid detections with a single hit they will be lost, but if you have passings with low hits then you should check your setup as a single hit suggests there is a problem with the loop setup.