Is it possible that the ANT+ receiver in my watch is degrading over time?

I have a Garmin 920XT that has been logging my miles for almost four years now (bought new in January 2016, many many miles on it, swim, bike, and run). It has generally worked flawlessly in that time, but recently I have started getting significant data drops when connected to my P1 pedals (riding indoors). I’ve been trouble shooting (between the watch, the pedals, and my Kickr) and am starting to come around to the idea that the issues lie in the watch. Is it possible that the ANT+ receiver in the watch is somehow getting weaker? I dunno, like it’s getting old and needs more sleep or something? Is that a thing?

I don’t really feel like dropping the coin on a new one right now, but on the other hand I want a device that works and if I look at the cost per mile of this one I have more than gotten my money’s worth.


Probably some kind of interference would be my guess. I would test just one device as a process of elimination. Maybe it is the ant+ stick.

Yep, that’s what I’ve been doing. That process has led me to the watch. Thanks.

That sucks. Maybe garmin will help you with a refurb.

Thinking logically for a minute, as the receiver and display, a problem anywhere in the system is going to show up on the watch, even if the cause is actually elsewhere.

Decreasing battery life shouldn’t show up in the receiver, although it is possible that the antenna connection in the watch has come loose over time.

But my chief suspects would be interference between the trainer and the PM’s. Or possibly EMF interference from your home wifi, or even microwave.

Do you see the problem riding outside?

Yeah, interference was my first thought as well. Honestly I’ve had such strange technical difficulties over the past month that I’m just about at my wits end.

In the past I’ve had some issues with TR losing the ANT+ signal from my pedals, but it was always recorded perfectly on the watch (I always use both for indoor rides because I’m nervous that one will drop). But about a month ago I started getting wild drops, like almost constant, on the watch. Most of the time the ANT+ signal to TR (via my android phone) was still good. So it did that for a week or so, and then I had a week of the watch working perfectly, then it starting going crazy again, repeat, repeat. For example, here are my last two rides, both Petit, both done under exactly the same conditions (in terms of what’s going on around me that could possibly cause interference).

I can honestly say that nothing has changed in my ‘training environment’ recently. Same devices, same fans, same kitchen appliances.

Another data point here is that I’ve never had any issues using the pedals with TR via BLE. it’s just that I would rather use ANT+. My Garmin is only ANT+, so I can’t compare signal drops there.

Riding outside is a good question, honestly these pedals haven’t been out for months. All my outdoor riding is CX right now, and I have a quarq on my cross bike. Looking at the files it’s pretty hard to tell if the signal dropped or I was just coasting around a corner.

Any ideas are welcome.

Does the quarq get data drops with the watch?

Can you open up the watch to see if there’s any corrosion on the circuit board?

Honestly it’s really hard to say. My quarq is on the CX bike and I rarely have more than 10 seconds of steady pedaling in a CX race. Looking at the file I can’t tell if I see a dropout or just me coasting.

That’s a great idea, but given my track record with such things, I just know I’d fu*& it up.

Things have been working for the past week now. I made two changes:

  1. I bought a long (15 ft) USB cable, so now my ANT+ receiver is actually positioned under my trainer, about as close to both the Kickr and my pedals as you can get.
  2. I stopped using my watch and TR at the same time.

I am cautiously optimistic. Could the issues I had be caused by pairing the pedals to both my watch and TR (on the phone) at the same time? I want to stress again that this is all new. What I mean by that is that I’ve been using the watch and TR at the same time, and using the regular ANT+ receiver (plugged directly into the phone) for years, including during my IM training last winter/spring, and hardly ever had an issue. If I had been having these issues from Day one then I would totally believe that they stemmed from the ANT+ receiver or the watch+TR combo. But since it’s so new, I question what the real culprit is.

Thanks to all, any more ideas are appreciated.

ant+ is a broadcast signal so it shouldn’t make any difference how many devices it pairs to. Distance does make a difference though and I also have my ant+ usb stick right by my quarq when indoors, was having dropouts with it connected to a computer 10ft away but never dropped with my garmin computer on an out front mount.