Odd Garmin radar Varia™ RTL515 behavior
 

I've had the version 1 radar since 2015 or whenever it was they released it, and about 8 months ago, I upgraded to a RTL515 when it was on sale for $150. The light is vastly improved, and the radar appears to work as well.

Within only the last 2 months (having changed nothing apart from doing firmware updates), when I stop on the bike, and then start out again, I get a series (sometimes between 10 to 20) immediate false positive warnings in rapid succession, even if the road is deserted, or if I am on a trail with no cars. I've removed my saddle bag to test if that was the source of the false positives, but it was not. This seems to happen intermittently, rather than at every instance. It can be quite annoying, especially if starting out on a road where I would benefit from having the radar working reliably. Once the ride is underway, everything is fine.

I've done a factory reset, and as mentioned I do all of the firmware updates.

I'm using an Edge 530 as a head unit, FWIW.

Anyone else have this issue, or have any suggestions for what else to try?

when stopped almost anything seems to set it off. even walking behind it can do it. I usually only get a few. but when stopped it can be a pain for sure.

It doesn't happen until I re-start.

I've only had one experience when the radar picked up mystery ghost cars that absolutely weren't there. I was riding gravel, explored a side trail, and picked the bike up and rotated it 180 degrees when I reached the end. I think the motion of the bike confused it.

What you're describing is hard to troubleshoot because it happens in a way that seems non deterministic. I didn't see this the last time I paused and resumed a ride but that could be the random part of it.

I suspect you can get Garmin to replace it without much push back. If it was my decision to make I would want to know why it's doing this first, maybe you've found some weird edge case and a replacement would have the same issue, although I doubt it.

I've been using the radar since was 1st released by Garmin in back in 2015. I was actually a backer of Backtracker when it was a cloud sourced funding project before Garmin purchased them.

With their early version, the 500, I'd get false alerts every so often but nothing overboard. In the past 3 or 4 years I can't really say I've had any between the pervious 510 and my current 515..

I've had the 515 for about a year now and it's been rock solid. Maybe contact Garmin as something might have glitched out during firmware update or something else is amiss...

If you can describe any more of the pattern or steps you go through (like pausing a ride, using resume later, etc) I'll try to reproduce this. I'm pretty sure mine is the 515.

Well, I don't really do anything, except stop and then restart.

The latest example I have in mind is from Sunday. I rode about 5 or 6 miles, and then pulled to the side of the road to let others catch up. My Edge 530 auto-paused.

The radar worked perfectly, detecting the 1 car that would come along about every 5 min or so. If two cars appear, two blips appear on the display. The first one triggers a beep. The second (or if there are more, the remaining ones) also appear and move upward, pass me, and disappear from the screen. I don't get a second beep if there are two cars close enough together to appear on the display screen simultaneously.

I pulled to the side of the road to wait for a few others. When we had regrouped and they had rested, we continued. I suggested they go first, so at that point there was no one behind me. I gave them a couple of minutes of head start. There were also no cars behind me, and I pulled into the road and continued up a hill. (It doesn't have to be uphill to do this.) As I started off, for at least the next 30 to 60 seconds, I got a multitude (probably 20) separate sets of signals and beeps (which is distinct from the behavior of a stream of closely-spaced cars). There was no traffic at all.

That's it. No other variables that I am aware of. No wind. Minimal vegetation, thanks to it being a heavily burned zone.

Keep in mind also that it only started doing this recently, under conditions identical to ones where it behaved normally.

Unfortunately, I think you are right -- it might be a firmware glitch (or hardware defect). But it is transient, and doesn't happen mid-ride, but only after stopping and starting.

I also get it initially out the gate (literally). I can turn it on and it is fine. Roll 300 ft to my actuated gate, stop, wait for gait to open, and roll out. Only then do I get the flurry of false positive signals. In that case, my steel gate is closing as I move away, so it could be that. But agin, why didn't it do that until 2 months ago?

The only thing I can think of is that somehow this gets triggered when the Garmin Edge 530 auto-resumes.

Maybe the next step would be for me to turn off auto-pause and see what happens.

Most of my rides are in the city so my Edge 1040 auto pauses a lot for relights, stop signs and I usually take a 5 minute break at my halfway point... I've not had any issues with mine at all.

I'd just contact Garmin, I bet they'll take care of you..

Thanks. I am going to mess with it first.

It isn't quite annoying enough to send it back, but if it gets any worse or I get any more intolerant, I will take your advice.

i've "reset" a garmin computer before multiple times (with varied success). possible to "reset" the radar unit via the app/website?

You're not the only one. I purchased an RVR-315 during the sale earlier this year and it is paired with an Edge 830 that was also purchased at the same time. After turning it on and before starting a ride, it will operate normally while parked by the street. However, once I start pedaling, it will give me a series of false positives as I get rolling. At first, I thought it might be all the mailboxes or something but it's not and it does the same if I'm starting a ride in a more remote location. After the first 15-20 seconds or so, it goes back to normal.

When stopping to take a break, it will continue to operate normally and will pick up cars passing by or even fellow riders walking or riding behind the bike. Then, just like you, when I get back on the road, it gives me the false positives for several seconds before returning to normal operation.

I don't recall it exhibiting this behavior when I first purchased it but it definitely has been happening the last 2-3 months. Like you, I'm wondering if the auto-pause has anything do with it or maybe there was a glitch in a Garmin update.

could be detecting the pedal stroke, or chain links.

I am not alone in the world after all!

It sounds like the identical problem.

I haven't had a chance to mess with auto-pause yet, but thanks for the reminder. I have the sensitivity turned up (lower MPH to trigger auto-pause) because I am so slow on 20% grades, and having it auto-pause while grinding up a hill is demoralizing. I think it might be simplest to just turn it off for purposes of this test.

I rode with mine today and went 28 miles all City.. I was paying close attention to auto-pause because of this thread.

I auto-paused A LOT for relights etc and had no issues at all..

I think it could be the top of your tire. Is the light in front of your rear tire? How high above? What kind of tires do you have (deep tread/lugs)?

I have auto pause turned off and have never seen the behavior you described.

I just turned it off, but haven't gone for a ride with it turned off yet. I'll update as soon as I have a result, but absence of the problem of course isn't definitive. If it persists, at least we will know it isn't auto-pause. I had it set to 1 mph, and have noticed it tended to go on and off while I idle and twitch and fidget while standing with the bike, so I am hoping it has something to do with that.

Mine is quite low, lower that officially recommended (short legs and a saddle bag). I use both slick 700C and lugged 650b.

But I also get it on a different bike that has it mounted on the saddle rails.

Yeah, I think you just hold the button down for 8 seconds or something like that. I don't think there is an app/website way to do it.

So I did a short ride as an experiment, with auto-pause turned off. The results were slightly ambiguous.

1. I didn't get the usual 10 to 20 false positives when I stopped the bike, and then resumed, without touching the Garmin.

2. I didn't get the usual 10 to 20 false positives when I stopped the bike, paused the Garmin manually, waited, and then unpaused the Garmin manually, and then resumed.

3. I saw a friend walking. I stopped to talk to him. A few minutes later I realized I had not manually paused the Garmin, so I did. I unpaused it and tried to ride off, but got sucked back into conversation, and paused and unpaused probably 2 more times. Then when I unpaused and finally resumed the ride, I got about 3 of the false positive alerts in rapid succession, but then all was fine again.

So, based on this, I think it is the auto pause/unpause repeating that somehow induces the later false positives on the Garmin.

However, when I tried to simulate that by pulling to the side of the road and pausing/unpausing several times before resuming, I was unable to reproduce the false positive alert.

I'm going to leave it in manual pause mode (auto-pause turned off) for at least the next week and see what happens.

Polaris, I've been paying extra attention to my RTL515 since you posted this -- and have seen no false positives after stopping. I'm going to agree that you should contact Garmin -- in my experience, it's pretty easy to get a human on the line.

On the plus side, at least a false positive is better than a false negative with this sort of thing. :)

I've refuted my hypothesis that this has anything to do with the autostart setting. (Yesterday, with autostart turned off, I started my ride and it immediately started doing this, again.)

I guess I will have to contact Garmin.