ANT+ Connection Issues

Did the Half Monty this morning (8 weeks into a 12 week training plan). I’m fairly pleased with the result, EXCEPT my HR sensor (Garmin Forerunner 35 watch) kept losing connection to SYSTM, and even when the connection was showing as ok, the HR shown / recorded on STSTM was sometimes significantly lower than what the watch itself was showing.

Any thoughts on how to reduce or eliminate the dropouts and data mismatch?

Were any of your other ANT+ devices affected in the same way? It might be a failure of the watch to properly broadcast ANT+ data and not a failure of the watch. This is why I use a dedicated device for HR, namely a Garmin HR-Dual.

My trainer was also connected via ANT+ (Tacx Flux) and had no issues that I noticed. I work in a bike shop, so I may pick up a hr strap at work today.

What platform were you running SYSTM on? We’re you using an ANT+ dongle? I use a notebook PC, put the dongle on a 1/2 m usb extension cord, and let the dongle dangle in free space in front of the bike. I get solid ANT+ to the trainer, cadence, HRM. That said, I switch the trainer to BT when using SYSTM as I get latency wtih ANT+ that I don’t get on ZWIFT or Trainerroad.

Windows 10, custom built desktop PC (ASUS MB, Ryzen 5 CPU), Bluetooth and ANT+ USB adapters on USB extensions to put them within 1 meter of the trainer (right around the bottom bracket). Since I have the option to connect via Bluetooth, I may connect the trainer that way to see if that helps.

Sounds like you got your dongle dangle dialed. My setup worked even when I was within a couple of meters of my wifi router, which are sometimes blamed for interfering with ANT+. Since you have BT capability, might connecting the watch HR via BT be worth a try?


Unfortunately, SYSTM doesn’t find the watch via Bluetooth.

BTW: My PC is hardwired into our network, since the Wi-Fi doesn’t do well in our basement.