I’m probably doing something wrong...

[BarbieW]

Hi everyone, sorry I’ve not been very active on here lately. Just been lurking, and struggling with the fact I am apparently “clinically vulnerable” at the moment

I splashed out and bought myself a reconditioned Forerunner 35 for last Christmas, but I suspect I have got something wrong and would welcome any views, please?

I have used Strava on my phone from my first runs and thought I could do with leaving my phone behind so got one of those magic watch thingys. Well it may be pretty but it doesn’t seem to know much about distance around here. I find it is telling me about 1k different to my phone, which naturally I still carry (it is my towel after all)

In those golden days before lockdown strava told me my parkrun was 5.2k, and I was comfortable with that. But my Garmin told me it was 6.3k. How can that be?

This morning I ran 10.2k on Strava but it was 11.5k on my watch. I know which I’d rather believe but bearing in mind the Parkrun difference, I just cannot believe the watch.

Have I totally wasted my money or have I failed to do something important, perhaps?

[Grannyhugs Graduate10]

Yikes that sounds odd. I have a garmin 35 and am pretty confident of its accuracy. However, there have been a few occasions when I’ve been in the mountains where it is unable to get accurate gps signals and on those occasions only gives spurious readings, always adding extra Km’s. If you are in an area that is likely to have poor gps signals this will be your problem, but seems unlikely if the problem is happening on a number of routes. Is there anything on the Garmin FAQs

[UnfitNoMore Graduate10]

My Garmin measures under usually 🤣

I spoke to Garmin about the issue and they pointed out that my smartphone had a similar GPs accuracy to the watch, possibly slightly better, and this is compounded when the phone is receiving a mobile signal as it uses this to assist the GPS accuracy... and there’s no way the watch will compete with it then.

One tip they did give me was not to press start when it declares itself ready... the GPSr is at this point locked onto 3/4 satellites out of a choice or about 8 if you’re out in the open. If you wait for a few minutes after the watch says “ready” it’ll check all the others it can see and take the 4 signals that it trusts the most (there’s some very complicated stuff going on with pseudorandom codes, which is boring, but the receiver can tell which signals are most accurate because of it). After that conversation I have my watch locking on as soon as I am outside, and just have to stop it turning GPS off a couple of times while I warm up. Since I’ve been doing that, the difference between watch and phone is about half what it was before.

[grumpyoldgirl]

Mine is never that far out! Does the run map look accurate? The only time my watch has failed is when I've started the run before my watch was ready. In that case, I can see from the run map that it's started calculating from when it picked up the signal.

[BarbieW Graduate10]

Thanks GOG, I hadn’t actually looked too much at the run maps and yes they seem way out if not non-existent. Some look pretty weird - did I really go there?

And thanks UNM - I need to be more careful about setting it up before I go. I will try to set it going way before I actually start running and see how that goes.