HRM-Dual does not perfom test HRV on my Forerunner 745. Connection is OK, but I get no readings or the readings are fixed at a number such as 72 or other for a long time even if i jump for a some time.
I have perform a test: link HRM-Dual to Strava. and is the same problem. Sometimes doesn´t give readings, other times gives fixed reading, and comparing with the readings of the FR745 are very diferent.