Ahoy @msknight
some time ago I asked similar thing here
I would suggest Kuri but indeed as I read in the forum it seems the bluetooth part of it doesn’t work. Also in the app description it mentions that developer didn’t have bluetooth ΗΡΜ so he couldn’t test it.
If you already have any chest strap or have access to, could you try to make a test ?
I have a strap but it’s not bluetooth, it’s Ant. Well, I’m seeing straps saying Ant+ and bluetooth, so I’m assuming they’re both different.
Hi msknight. When it is ANT + you can use any bicycle gps tachometer that supports ANT + like sigma devices (e.g. https://amzn.eu/d/iIsVBgT) or another ANT + receiver device.
Here you have a working example which I use with lastest SFOS and my Xperia 10 III:
I use this HRM mainly with cycling: Kuri 4.5 + Polar iWL hearth rate monitor. I know that it is old device (no support for Bluetooth Low Energy but only Bluetooth 2.0 standard) but works as expected. 
Thanks. I tried briefly getting hold of Kuri but it didn’t want to install, can’t find RPM installation or something. It’s late here so there’s probably something I’m missing in the instructions. I’ll sit down and have a proper look tomorrow.
I have it installed. Obviously, it won’t talk with the CSX chest band so I’ll have to shop around now for a bluetooth one. We’ll see what happens. I’ve e-mailed Polar for their recommendation.
I 'm using a Wahoo tickr with BLE and it works well with Kuri on my XA2 plus latest Sailfish.
Installed and tested working… ish. My phone and Kuri have concluded that I drink a bottle of Vodka before going on my morning walk. I also can’t find the setting for miles instead of killometers, but I wouldn’t be surprised if that’s not on the developers radar. I consider myself lucky to have this and I’ll probably send the developer a note of thanks in due course.
With regards bands, I ended up settling on a Garmin HRM-Dual, after watching various comparison and testing videos. We’ll see if this works, but with GPS data on a walk out by this much, I’ll have to test against other devices with my friends, to determine whether it’s reasonably accurate or whether I should just get a watch. (so far it’s also stuck trying to upload the short walk to Strava. Not a good sign)
Concerning Strava upload - see the latest discussion in the other post [4.5.0.16] Kuri doesn't start - #43 by Ahtisilli
Thanks. Mine turned out to be, although I put a name for the walk, I didn’t put anything in the box below. Once I put some text in there, it went up in a flash.
Interesting. I’ll try it next time I encounter the problem. It’s still easier than logging in again or refreshing.
@msknight Check with another gps app to see the paths and check your Settings → System → Location gps settings. Usualy GPS antenna is located on the top of the phones, did you have the phone in your pocket facing down or something?
About miles, I had a look at the source code and it seems it supports only km/h. Try contact the maintainer / developer to add a setting for miles.
Also, how was the experience with the Garmin HRM ? Did kuri mention calories / heart rate diagram in relation with the activity?
I’ll have the phone on my upper arm tomorrow, hopefully. I have an arm strap so next time I go for a walk, I’ll try that.
Once it’s in Strava, they convert to miles so I’m not going to trouble the developer; they’ve already done a lot to fork the app.
The Garmin HRM only came this evening. I’ve paired it and Kuri sees it and can talk with it on BLT so next time I do a walk I’ll see what comes out of it. Unfortunately I’ve got to go shopping tomorrow morning before work, so it’ll be a few days before I get the chance to try it out.
Thanks all for the help.
Kuri installed on the latest Sailfish running on the Sony Xperia 10 III and the map works well. GPS is just, what it is. I was walking through woods, etc. and it’s accurate enough for my needs. The figures are more important to me.
The developer of Kuri said that imperial is on their radar but life is busy so development is stalled for the moment. However, the upload to Strava works well and that converts so that’s good enough for me.
After viewing tests of chest straps I settled on the Garmin HRM Dual which transmits BLE and pairs with Kuri which can see it fine.
Looks like I’m set to go. Thanks all for the help and advice.
I have developed software myself in the past, but I started in Cobol and 6502 assembly, worked through Pascal and ended with PHP and MySQL. Re-training to Java is one of those things on my radar, but life and work is getting in the way. Maybe I’ll find the time next year to re-train and start writing myself. Cross fingers.
Good to hear you had a solution in the end for this quest!
As for SFOS development, Javascript is needed for QML apps and maybe sone C++ here and there. Nothing as fancy as 6502 I guess;)
You can do a lot with python, too I enjoyed 6502 assembly, though I did more Z80, 8080A stuff and I’m too young (cough) to have learned Cobol. One of my great aunts was a Cobol programmer of the first generation. This summer she was reminiscing how she loved debugging. Of course, she also enjoyed writing SQL when that came along!
Are you serious? Do you know how much time I wasted to try to fix the low accuracy when the screen is off and now you are telling me it was not the screen but I was just holding it wrong™ 
Joke aside. I need to test this. When I did not put the phone on the arm it was in the jacket with the screen off aaaaaand facing down 
@elBoberido let us know the rest results! Did it help the up-side up? You could also try with connected powerbank and Display setting “screen always on on charge” to have reliable results 
Also, GPSInfo might give you some info about GPS signal reception.
@nas I don’t have conclusive results but it looks like it is related to whether the screen is pointing at the body. It does not always have an effect though. Maybe this only happens when additionally not many GPS satellites are available or the connection to one is lost. I need to observe this for a longer period. Maybe others could also check whether the GPS accuracy remains good when the phone is in the pocket and the screen is pointing away from the body.
@msknight this might also be interesting for you
After also testing with a GPS watch, it just seems to be general inaccuracy as a result of cloud cover and trees. Although there are things that can be done with the phone to help, it seems that in poor conditions there are limits. The GPS watch can also be switched to Glosnass and other sources as well simultaneously but the rate at which it eats battery, I didn’t bother. So it looks like I’m as good as I’m going to get.
