Made a small discovery today for those that have trouble with the PT picking up a HR signal. Took just the head unit (and strap) to spin class today and just set it on top of the 'stem'. Whenever I stood up it would quit receiving. Played with it a bit and discovered that the sensor definitely works much better when the bottom of the CPU is pointed at the transmitter. If you are having trouble on the bike, tilt the CPU forward so that the bottom points more towards the strap and see if that helps. - TF