Very poor ANT+ signal performance, but everything works great?

Hi everyone!

I’m using the following equipment:

Tacx Flow Smart

Bryton Ant+ HRM

Garmin Vector 2 powermeter pedals

Generic top-grade Chinesium Speed/Cadence sensor (only cadence paired)

The Gamin USB stick that came with the Vector 2 pedals.


The thing is, I had the stick just dangling from a 90cm USB extender in front of the bike and I was getting quite a few dropped RXs in all ANT+ channels according to zwiftalizer, around 6-8%, and apparently this was enough for my signal to qualify as “very poor”. I didn’t get any dropouts and the only thing I noticed was that my trainer was slow to respond to gradient changes. It would take it about 5 seconds to react to the gradient changes on the screen.

I found another USB extender lead and chained them together. The ANT+ stick is now hanging LITERALLY 10 inches from the side of the trainer where the ANT+ antenna is. Now the trainer reacts VERY quickly to gradient changes but my RXfails in zwiftalizer have gone THROUGH THE ROOF for all the devices, often exceeding 15%. The thing is, altough I seem to be dropping almost a sixth of the ANT+ packets, everything seems to be working smoothly… Packets are being lost at that rate for EVERY device and not one of them is further than 2 feet from the ANT+ stick. Powermeter, cadence and trainer are within a foot. I also set up my WiFi to stick to channel 1.

Given that things seem to work just fine and I probably would never have found out if I wasn’t obsessively checking Zwiftalizer after every ride should I just ignore this and just ride? I’m somewhat worried that the pedals or the trainer might lose signal in the middle of a race or long group ride and I’ll get screwed.


Quality ANT+ dongle, device distances, and possible interference boxes are all checked… Is there anything else I might be missing? Or is it just that ANT+ dongles and/or zwift start losing it if you pair 4 different devices simultaneously?

Here is a helpful link for you: