When setting up multiple timing lines using ground antennas, there is some key information to understand. 

• The most common reason for missed detections is participants directly blocking the transponder with their arm when stopping a GPS watch or device. Spacing lines apart increases the chance that the chip will not be blocked.
• Transponders cannot communicate with 2 different readers at the same time, so a minimum distance of 3 m (recommended 5 m) should be kept between detection lines placed one after the other (e.g. a main line and a backup line). When setting up two systems next to one another to cover a wider detection line, it is better to have a dummy element in the middle, not sending any signal. For this, you can either add one dummy element from an extension, or simply not connect the last element of one of the antennas.
• A decoder will switch through all the connected antennas approximately 25 times per second, at any given time only one antenna is active, using a single decoder is therefore technically reducing the read time on each line.
• If using EU frequency decoders, it is necessary to set the Channel for each decoder accordingly, by default this is set to Auto. There are 2 options "A" and "B", these should alternate between decoders to maximize read rates. This should be set back to Auto when the decoder is used alone.

Use cases:

Two decoders, main and backup:

• Set up the antennas at least 3 meters (recommended 5 meters) apart
• If operating on EU frequencies, make sure to set one decoder to frequency A, the other to frequency B.

Two decoders side-by-side to cover a wider detection line:

• Use hinges to join antennas in the middle
• Make sure to have one element in the middle not sending any signal. For this, you can either insert one dummy element from an extension, or simply not connect the last antenna on one of the two decoders (connect cables 1-7 of the antenna, leave cable number 8 not connected).
• If operating on EU frequencies, make sure to set one decoder to frequency A, the other to frequency B.

4 decoders, main and backup line, side-by-side:

• Observe the same precautions as in the examples above
• If operating on EU frequencies, alternate frequencies A and B on your decoders as shown below

4 decoders with extension, 16 m main and back up line:

• Remove one dummy element in the middle of each 16 m line, so as not to have 2 dummies side by side. On each line, one side should have 13 elements, the other 14. With 27 elements, you can cover up to 16.2 m.
• Otherwise, observe the same precautions as above.