GPSrChive Discussion Forum

I am unable to get my GPSMAP 66 units running both firmware v2.50 and v2.80 to connect to my HRM-Dual - anyone else have any better luck with any HRM?

The HRM battery was flat because I hadn't used it for a few years. Replaced the battery and it connected via Ant+ with v2.50 with no problem. I just updated to v2.80 and haven't tried it yet.

Just tried it with v2.80 - connected immediately. Do you know that it disconnects when the screen is blank in Expedition mode, but reconnects when the screen is displaying stuff.

feraltek wrote: ↑Mon Apr 01, 2019 12:10 am The HRM battery was flat because I hadn't used it for a few years. Replaced the battery and it connected via Ant+ with v2.50 with no problem. I just updated to v2.80 and haven't tried it yet.

feraltek wrote: ↑Mon Apr 01, 2019 1:22 am Just tried it with v2.80 - connected immediately.

Which HRM are you using?

feraltek wrote: ↑Mon Apr 01, 2019 1:22 am Do you know that it disconnects when the screen is blank in Expedition mode, but reconnects when the screen is displaying stuff.

I suspect this is normal behavior for Expedition Mode.

This type, but with a plain stretchy belt, purchase via eBay about mid 2012.
https://buy.garmin.com/en-AU/AU/p/15490

The GPS 66S keeps recording when the screen is blank by using it with battery save mode instead of expedition mode.

It’s a lot more than that. Expedition mode will turn the GPS receiver off as well,
and most modern controllers have a low power sleep mode that can be set to wake up at intervals.
It will wake up, turn everything on to get a position, record a point, and turn everything off again.
I made a home-brew GPS that can do that.

In expedition mode it recorded every point of the whole track in both the GPX and the FIT files, while the screen was blank and while it was displaying maps and data, but nothing else. It's a pity we can't select other functions as well. I advised about the HRM in expedition mode and also he battery to help with troubshooting.

Not a GPS, but years back I programmed 6502 microcontrollers in Forth and Assembly to go into quiescent state to save battery, waking up at a set interval for a few milliseconds to sense and record data. This is just to let you know that I understand what you wrote.

feraltek wrote: ↑Mon Apr 01, 2019 3:18 am This type, but with a plain stretchy belt, purchase via eBay about mid 2012.
https://buy.garmin.com/en-AU/AU/p/15490

Thank you!

I thought maybe it was the sensor, but then I tried with an eTrex, and it connects without issue, so I am certain it is the GPSMAP 66...

Have you tried other connectivity features - WiFi, Bluetooth, cadence sensors, etc. I don't know if there's anything in common with them all - it's just a stab in the dark idea in case it shows up anything.