Broadcasting Questions

Broadcast as it says is just kind of transmitter. It is up to receiver which "station" it want to use and listen.

To be honest I have never tried to check what would be to have two HRM (and if that is possible at all) connected at the same time to my FR955

All your receiving devices will listen to selected by you HRM transmitters.

It could be FR955 broadcast to your smart trainer. It could be your HRM Pro too. It is your choice

Some of Garmin gizmos can broadcast using ANT+ some can use BLE and some can use both of those technologies.

And final question. At the same time several receivers can listen to the same transmitter. You could have HRM Pro data used on your Watch, your smart trainer and your Bike Computer too. All at the same time. 

I don't use HR broadcasting, but I do have a couple of devices to test with (955 and 935)

B1nny said:

Two devices show up on the PM5 unit when I set-up a broadcasting connection. One is Forerunner and the other is ANT+[id]. Why two? I would have assumed that the Forerunner option was a BT connection but I’m sure broadcasting only works over ANT+?

Recent Garmin watches support bluetooth broadcasting: https://www.dcrainmaker.com/2020/04/quick-how-to-garmin-wearable-heart-rate-broadcasting-to-apps.html

I just tried broadcasting from the 955's HR widget/glance and searching for external HR sensors on my 935. The 935 initially shows a sensor called "HR - [ANT+ ID]". If I select "Show Bluetooth Sensors", it shows "HR - Forerunner", so your assumption is correct.

(I checked the PM5 manual and it says both ANT+ and Bluetooth are supported, ofc.)

B1nny said:

If I wear a HRM Pro Plus chest trap connected to the watch, will this be broadcasted? (Source switching off)

According to this comment on the article linked above, it's at least possible in some circumstances:

Another tip you can use “Virtual Run” to broadcast the HR from an external ANT+ strap (almost all legacy Garmin straps) this will generally give much better accuracy than the built-in oHR.

I'm not 100% sure what would happen if you enable Run (or other activity) Settings > Broadcast Heart Rate. I did notice that older watches had a similar option (in a different place) which was explicitly only for the wrist HR. e.g. 935 has (General) Settings > Sensors and Accessories > Wrist Heart Rate > Broadcast During Activity

So it's possible that newer watches will broadcast either wrist or external HR when this setting is enabled.

My guess is that if broadcasting was done via the HR widget/glance, that would be wrist-only (but I'm not sure about that either).

B1nny said:

If I use a smart trainer connection (FE-C) which does work and receives the work out data, I would also need to connect HRM to the unit to display HR. Will this data also be sent to the watch - given HRM is also connected to the watch directly? I’m concerned about duplicate or competing data.

I don't have any personal experience with this, but some ppl have reported that when they connect to a trainer with Fenix 6 or 945, wrist HR no longer works on the watch itself (other than broadcasting), but external HR still works.

www.dcrainmaker.com/.../garmin-shows-off-smart-trainer-integration-on-fenix-6-forerunner-945.html

No idea if this was ever a problem with the newer watches.

Broacasting works perfectly,

I use it for my cycling indoor session.

You only need to select Virtual Run.

No need to start the activity.

Dont forger to disable heart rate alert otherwise you will get ....recuring alerts.

It looks like the 955 should support BT broadcasting within any activity. When I broadcast in the rowing activity (enable broadcasting in activity settings) there a two connections showing; one ANT+ and a BT one named Forerunner. So you shouldn’t need a workaround via virtual run.

I wonder if enabling this for every activity will not unnecessarily reduce the battery life.

And in my case with the Virtual Run, you don't need to start the activity to send data as the external application will collect them. Which does not unnecessarily reduce the battery life.

FYI, you enable the broadcasting individually in which ever activity profile setting you want, so you could do it for Indoor Cycling only. Virtual run will still use battery broadcasting over BT as it would broadcasting in the Indoor Cycling activity. I get that you don't have to start an activity for virtual run though, so there may be a small activity battery saving there, but not much compared to broadcasting itself.

If you also disable Source Switching, it will turn off the OHR on the watch whilst connected to HRM which saves a lot of battery.

My understanding of Activities is that they setup set of settings / profiles which otherwise you would need to do one by one in various places. Like Treadmill or Virtual Run would switch off GPS.

In any case BLE is Low Energy, but still energy. It HAS to decrease battery life but how much?

PJohann, have you noticed that in Virtual Run settings, you can actually switch off HR Broadcast?

I guess Virtual Run broadcast more data than just HR. 

I tried it a few weeks ago with my indoor pedal bike and I enabled broadcasting, but my app couldn't find my watch...

I'll try again this week to see if anything changes regarding energy consumption and if it's the simplest solution for me.

The less I click, the better I am.