Unfortunately I can not recommend, had sent him to pesky three weeks back these absolutely chest. The Reasons: - A total of 12 trainings, I wanted to do with the chest strap, this has provided only 3 times throughout the training period (70 minutes) reliable RF data. He quit during training at other times or was not recognized by the device despite several attempts to connect. Software reset, reset Bluetooth, even deleting and reinstalling the app Runtastic who can not change that. - The track record of runtastic without chest strap is in particular wooded trails with a measuring error of about 10% only moderately, but still better than the track record of other smartphone apps. With chest strap increases the measurement error to an estimated 20% and - worse noch- the app rises again completely from the track record, because supposedly no satellite channels available. This way, not only in the forest, but also in the open field. For 2 weeks I walk again without chest strap and my Runtastic behaves normally again.
When I think about how much time I faith- plugged into the failed connection attempts, resets and software installations I could easily fit can train twice as much! And the annoying: It changes nothing, all measures have failed!
It is fair to say that it may be due to the programming of runtastic that performance when connecting the chest strap geht- as to its knees but if you listen to the I-Phone music, surf the Internet, can make phone calls while Runtastic continue running properly in the background, can not tell me that the connection of the chest strap so had to affect the performance of the app at this point is obviously programmed poorly or incorrectly. And, moreover, makes it anyway no difference whether the app or the belt blame actual it runs just not why only one star and chest strap back.
