To confirm your settings, you need to check the read height by using one of your transponders. Therefore proceed as follows:

1. Stand in the middle of your loop, holding a transponder high above the loop.
2. Slowly bring the transponder down, until the USB Timing Box blinks, indicating a read.

Make sure that you start detecting transponders slightly higher than required. For example, on a cycling event with transponders at the fork, you need to detect at least at knee height, so you should setup your loop power to start detecting mid-thigh.

If you do not get the expected read height, increase or decrease the loop power.