Losing all Ant+ signals at once

Hi, I have been searching these forums and everywhere else, trying to fix a recurring problem.

My preferred setup is to run Zwift on a Dell xps 13 notebook (Core i7) running Windows 7 pro, with ZC on my phone. I used to use BTLE connections through ZC but I was experiencing loss of connectivity, so I bought a small USB Ant+ dongle (the Dynastream micro one like they make for Garmin) and an extension cable. The dongle ends up a couple of feet off the floor, near me and the trainer.

I have no trouble establishing a connection to my Kickr Core and Tickr - everything starts out fine. But often after a few minutes, or 20 minutes, Zwift abruptly loses all signals - the devices show as being paired, but they all say “no signal” at the same time.

Most of the material I see online and from Zwift help addresses signal dropouts or problems establishing connections, not my “everything is fine and all of sudden all device signals are lost at once”. The program runs fine, the dongle works fine, the device driver is up to date, the connections start out strong and when they disappear it’s always both devices at once, suggesting it’s not the Kickr or Tickr at fault. (And indeed, if I run Zwift on my phone - small screen! - with BTLE connections everything is stable.)

Disconnecting and reconnecting the dongle doesn’t help - I get the Windows beeps on both actions, but it does not solve the issue.

Exiting Zwift and restarting it DOES generally fix the problem, but often not for long before it repeats, and it destroys the ride experience. The fact that not touching the hardware but restarting the program re-establishes signal connectivity makes me think there’s something going on that involves the program.

I have disabled power-saving options for the dongle and USB ports both in the Device Manager and in the notebook’s power management options - thinking that could explain the sudden loss of signal. But it has not solved it.

I very much like Zwift, and it’s been a godsend with the Covid gym closures this winter, but this problem is super discouraging. I’m posting this here is the hopes that someone else has had a similar problem and can suggest a course of action. THANKS!

Could be a faulty dongle, cable or USB port. It’s possible for a component to be marginal and then as it heats up through use it drops out and then starts working again soon after.

You’ll need to go through a process of elimination to work out what’s going wrong. It’s easy to try another USB port. Extension cables aren’t expensive, to try another one of those.

Thanks for the suggestions.
The cable is new.Switching ports doesn’t help.
I’ll acquire the Simulant+ software and see what the computer sees from the dongle when Zwift has problems - I just hoped that someone had a bright idea that would help me jump to a solution.

Did you try to check the log file @ zwiftalizer.com?

Well the forum is littered with similar posts but it is interesting that they do normally center around drop outs rather than these competely disconnect issue that is I agree subtly different .

Here is another example of someone experiencing same

Worth following that as a lot of the normal pointers to what causes ANT dongle issues are covered . But also to raise the ante a little that there MIGHT be something going on here causing this issue to be reported more than once . It is possible a bug has been introduced , but I have to admit if it is then you are going to have to work hard to get them to acknowledge let alone fix it as Zwift are not going to be that interested in picking it up without a lot of evidence and/or reports of same issue . Now it is possible this is happening outside of the forum and that would helpe cause , so first advise is

report it to support email ( but expect a canned response with things to try rather than real engagement . Follow up on it , you might get lucky …

You are going to have to invest some time however IMO to self diagnose it , using Zwiftaliser and if possible first alternative components to rule out things like OS/Hardware issues.

Mark, this smells suspiciously like a USB dropout as folks have mentioned. Take a look at your log file in Zwiftalizer.com. It would be interesting to see if this is the only dropout or if you are riddled with dropouts and finally you have one that is extensive enough to not recover from. With a good picture of what the ANT+ signal looks like in Zwiftalizer, then do a test without the extension cable. One would expect the dropouts and signal quality to get poorer, but see if that is the case.

Is there any metal near the dongle? For example, my laptop is on a metal music stand (thus extension cable is necessary as dongle in the laptop gets too much signal blocked by the metal stand) but when the extension cable is within a few inches of the vertical post of the stand, even when on the Kickr Core side of the post, it still has problems I presume due to reflections. I have to hang the dongle a little further away from the stand’s post then it works great.

Next thing to suspect is the dongle itself. One would suspect the Garmin dongle should be good quality, but you never know. Where are you located? I’m going to guess Canada as the Dynastream appears to be common for Garmin Canada. If so, I’d suggest getting an ANSELF dongle from Amazon. The ANSELF is inexpensive yet seems to be one of the most stable devices out there. I had lots of problems until I switched to it and things immediately became stable. I mention Amazon because it has free returns so it is a no-risk test.

All excellent suggestions, thank you.
I did look at a failed ride in Zwiftalizer - 14% dropped packets or so.
The site said a DC fan can create problems - I’ll move that farther away.
I’ll switch both the PC and my phone to a 5G wifi connection, to get out of the way of the Ant+ frequency usage.
And thanks to your suggestion, I’ll move the dongle farther away from my music stand.
Yes, i’m in Canada. If the above don’t work, I’ll order a new dongle.
Thanks again, Mark

I had something similar recently, where everything would happily connect and I could start a ride but the everything would just spontaneously disconnect. Mine turned out to be the ANT+dongle, which had previously worked flawlessly for over 3 years.

The metal connection pins do become prone to failure after repeated use due to the heat and cooling cycle it goes through every time it is used, so just because a Garmin dongle may be good quality, it doesn’t preclude normal wear and tear on the connectors.

The fact that everything works properly when cold and then disconnects after it warms up does point to that as the potential issue.

Well, I have a little data, but too small a sample to conclude anything.
Today, I moved the DC-motor fan a few feet farther away, and I moved the dongle (at the end of the cable) away from the music stand, looping it through one of the (plastic) water bottle cages on my (carbon) bike frame. I checked my laptop and phone - both already on 5 GHz wifi.
I did a 1h30m ride, successfully. So that was encouraging, but like I say, sample of one so a little early to conclude anything (I had successful 1-2 hour rides in the past, just not lately).
Interestingly, when I compare the Zwiftalizer analyses for today’s successful ride compared to yesterday’s unsuccessful ride (all okay at first then “no signal” from all devices abruptly after 9 minutes) I see a weird thing.
Yesterday’s unsuccessful ride showed average RxFails of 11-15% between the two devices and zero searches, until all signal abruptly lost. The summary feedback was “Perfect! Your ANT+ devices were paired just once which means there were no dropouts after you started riding. Congratulations!” Yeah, congratulations, except it failed at that point.
Today’s successful ride showed average RxFails of 10% with 1 search on the Kickr and 33% with 9 searches on the Tickr, But I think the Tickr problem may have been with the strap not the receiver. In any event, the feednback was, “Yikes! Your ANT+ device signal was up and down like a fiddler’s elbow. Your environment is the most likely cause. Work through the recommendations below changing one thing at a time.”

So my “successful” ride shows lots of problems while Zwiftalizer thinks the failed ride was just great. Whatever was going on with the ride failures may not show up in Zwiftalizer . . . the abrupt loss of signal within Zwift doesn’t seem to be visible to the program.

So I’ll keep going with the current setup and gather some more data points. I’m not sure what evidence I’m gathering but as long as I can ride successfully it may not matter. Fingers crossed.

Mark, I am having exactly the same problem always drops after 17-20mins 3 times in a row driving me insane. Have tried new computer, new cable, new connectors etc. My son happened to connect into his school zoom (bluetooth off) at the same time it dropped today so will have to try with no other laptops on but thats just not going to work on a daily basis. This time last year everything works with no issues.

Yikes, “insane” is a good word for the feeling, isn’t it?
It sounds like you have tried all reasonable things and have moved on (like I did) to superstitious behaviors. :grin: You mention “cable” - does that mean you are using a USB ant+ dongle?
My problems went away when I finally upgraded from windows 7 to a laptop that managed Bluetooth properly. Things have been very stable for me since then - but given all you have tried, that doesn’t sounds like your answer.
It’s a black art!
If you are using ant+, there’s a program that let’s you log the signals and dropouts, and see some of what’s going on. It doesn’t provide answers but does help diagnose ant+ connectivity.
Sorry not to be more helpful!

As a general reminder to anyone using BT or ANT+:
2.4ghz wifi signals cause interference.
Other bluetooth devices causes interference.
Long USB cables causes signal degredation, even a 3m cable can be too long if it’s a poor cable.
Mirrors, metals, stone tiles and brick walls esentially blocks signals of any kind.

If you’re experiencing issues with BT or ANT+ it’s worth checking these things out by placing your trainer really close to your computer with no dongle.

You can also have the wrong drivers, this is a common issue.
Resolve this by going to the product page of the manufacturer of your device and downloading the correct driver and installing this.
Windows uses generic drivers and in my experience, these drivers can even cause a computer to crash to bios.
I trouble-shooted this issue for a year before i found this out, after upgrading the entire computer part by part… $$$$ :frowning:

If you’re going to use a long USB extension, try to get an active one (it has a built in amplifier in the end where you plug your dongle)

Hope this helps.

For those of you having connection dropouts when pairing with ANT+, I’ve been using this site for years.

Just drag and drop your Zwift log.txt files into the site, and it will provide you with a wealth of information about your connection. You should be able to identify issues consistent with signal interference, or even tell if the USB ANT+ dongle is faulty. Check it out!

Hint: After you load the log file into the site, the paragraphs of descriptions underneath the graph of your log file really explain what’s going on.