Zwift (Windows) loses the Ant+ connection with all devices after a few minutes of driving (trainer, heart rate monitor, cadence sensor)

Zwift (Windows) loses the Ant+ connection with all devices after a few minutes of driving (trainer, heart rate monitor, cadence sensor).

Hello everyone,

It has happened to me several times. Zwift abandoned connection with all devices. Usually after 10-30 minutes of driving.
Today I wanted to do an FTP test but the connection was broken after 24 minutes. So what did I do:

  • I unplugged the Ant+ antenna and plugged it in again. - result, nothing. does not detect any devices.
  • I switched the antenna to another USB port. - result, something moved, zwift found devices, connected and suddenly abandoned. And so he went through each device in turn over and over again. trainer - power - cadence - controla - heart, over and over again.
  • I restarted the computer, started zwift, turned on the ride, drove 18 minutes and flap, lost connection. Finally irritated, I turned off zwift and started writing this post.

A few weeks earlier it was the same, but the connection was abandoned after 10 minutes - only then I thought maybe the fault of the motherboard and USB controller, or maybe the fault lies on the Ant+ antenna side. I borrowed a laptop from my father, installed Zwift on it and connected the antenna and went through the whole training antenna works.
How to check if it’s the USB controller fault - I don’t know. : /
The keyboard works, the mouse works, the sound card works - is it the USB controller’s fault - the south bridge - I don’t know, the other devices work. : /

Does anyone know the solution to the problem? Please help.

I attach the log: 2nd log , 1st log

My devices:
Trainer: Tacx Flow Smart
Antenna: Tacx T2028
Heart rate sensor: Tacx T1994
Speed ​​/ Cadence sensor: Tacx T2015

Have a read through this.

I bought an Acer gaming laptop at the new year and I had similar experiences to what you are describing. Upgrading from a 2011 Dell Dimension, which Zwift ran on, but took forever to load up.

Ended up returning the Acer and getting a Dell G7 laptop and I’ve saw no Ant+ issues.

You can try checking in the device manager to see what the current is to your USB ports. But the link above gives some pointers, like checking wifi channel.

I’m sure there will be others maybe with a better insight than myself.

If you have a PC, you could try somethis like that

If you have a Notebook, you could try an active USB-Hub.

Or in both cases try another ANT+ Stick.

I also have a Tacx Flow Smart and had very similar issues with a new PC I was setting up last month as an upgrade to the laptop I’d been using for five years. Everything paired , all good, start riding, dropped out within a couple of minutes. Investigated all the settings I could find, turned off all power saving, nothing wrong, tried both BTLE and ANT connections with and without the companion app, bought a separate BT dongle, still getting dropouts. I was about ready to smash it all up.

As a last resort I tried a USB extension cable for the ANT stick. Perfect connection that stayed stable. Tried the bluetooth dongle, same. Has now worked perfectly for a month. Can only conclude that some PCs generate interference and putting the aerial a couple of feet away solves it.

I don’t know why trainers don’t come with USB sockets for the power/cadence/controllable part, to be honest.

I use a desktop computer. The funniest thing is that it happens every now and then, not every day. Once it works properly and once it doesn’t. Sometimes there will be a few seconds break (5 sec) in the first 10 minutes of driving, and then everything works normally.
My Tacx antenna has a 1.4m long cable. and this is the model.
I usually put it at a distance of 1m from the computer. Under the front wheel.
I will try the extension in the form of an additional usb cable. It will also lean toward the above proposal for an additional adapter for the USB port on the PCIE. The card will be cheaper like a new antenna. We’ll see if it helps.

Have you dropped the log file into to see if you are getting any signal interference with your ANT+ setup? I would start there before buying anything new.

What have you changed or moved around in your environment that could have caused this to start? For instance, I moved my fan and it started to cause signal interference so I had to move it to the other side of my setup, away from the ANT+ extension cable.

Good advice. I did not realize that something like this is available to the public as a “zwiftalizer”. I will try to grasp what came out.
The fact I did a slight modification in the organization, I moved the subwoofer speaker from left to right and was closer to the antenna cable. But shouldn’t such distortions be permanent as every ride on zwift? April 12 (break), April 14 and 17 (normal) April 19 (break).
I’ll check it, that’s a good point. The first will turn off the speaker completely, the second time I will move it to the left - further from the antenna cable. I’ll compare the logs.

Did you ever resolve this? I have almost exactly the same issue. Some days everything is fine, and others, after about 15 mins all connections seem to drop - the paring screen shows all devices connected, but it says no signal. The only way to get everything back is by restarting Zwift. It’s very frustrating.

Zwiftalizer says there were no ant+ dropouts despite the signal going blank after 15 mins on the graphs.

Hi @Andrew_Lord2, welcome to the forums!

A few things to try:

  • different USB port on your PC
  • USB extension cable to get the ant dongle right under your trainer
  • make sure no one is using the microwave
  • move your fan to the opposite side, away from the PC

Hi Mike, thanks for the welcome.

I have tried all of those things - If something was interferring with the signal, wouldn’t it just cause drop outs rather than the issue I’ve described? It feels more like a hardware and app issue - something causes the app to stop talking to the ant+ dongle without a restart.

Hi Andrew and Mike,

I haven’t been able to fix this problem lately.
But I recently purchased a bluettooh receiver:
ASUS USB-BT400 Bluetooth 4.0 USB Nano Class II
I hooked it up to check if it connects, but I haven’t tested it while driving. You know, the crown and these things have resulted in all race dates being messed up or canceled, so I didn’t get into training for the trainer. But give me a week or two, I’ll finally test this Bluetooth and I’ll give you the answer to see if it works better like an antenna.

Hi, I done a 45min ride. So i connect Via Bluetooth:

  • smart trainer (power) - showing watts
  • smart traner (candece) - showing cadence
  • heartbelt - is conneted but no data :confused:
    So i tryed switch battery in heart sensor for the new one. Zwift showed connection and full signal. And no results - no data from heart.

So tryed again with old Antena Ant+ and it recived data from heart.

I started a ride, conection via bluetooth is stable with no data loss, but old antena Ant+ losing data more than few times from heart sensor.

So i have a questions, meybe you know?
Did bluetooth 4.0 can conncect to only one device.
Or he can’t recive more than two strings data from multiple devices (or one).

PS: I had my antenna connected last year, for a period of several months it could probably be damaged by it.

I am having this exact same problem…I have my usb stick on an USB M-F extension cable & positioned below my rear brake caliper - works perfectly with no drops. Lately though I have a complete ant+ signal loss after a period of time (trainer, Hr, cadence all lose signal simultaneously) & the only way to restore it is to restart Zwift. I purchased a new usb dongle thinking this was the issue, but am having exactly the same problem with this new stick.
Extremely frustrating when trying to rack up some longer rides, and I am at my wits end on what to do next. Can anyone offer some advice?

Have you all made sure your USB devices power managements settings are set to not put the devices to sleep ?


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Hi Graham,

That’s an interesting point.

I see the usb’s are set up to allow the laptop to turn them off.

Thank you – let me modify and try again tomorrow and see if it helps!

Best regards


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Hi, after change to bluetooth. I had one drop signal, but disconnecting and connecting in menu zwift do not give result. After that i tired on/off bluetooth service without closing zwift and that solution worked (in windows 10 right sidebar on screen).

BTW: I buyed new strap for HR , and works. I have signal and data on Bluetooth connection. Update my Tacx Flow frimevire.
So now everything works fine. For now.

Hi Graham,

Just to advise you that my setup now runs flawlessly - thanks again for the advice!

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