I have nothing but problems wearing and recording rides using my Garmin Edge 820. I get so many drops and low readings and high spikes that the data is useless. I have three different Garmin straps and three different Garmin transmitters and have the same issues. I use to wear a Polar HRM and it worked flawlessly, but it didn't connect to my Garmin (too old).
Garmin recommended I try putting the transmitter on my back, and/or putting it on my side. I have seen various comparisons of datasets recorded by some reviewers who wear two or three different HRMs and see how accurate they are.
Has anyone here done this, and if so, does my Garmin upload to connect.garmin.com show all three datasets?