Fenix 6 military use for navigation.

tmk2 said:

things like basic navigation to waypoints, navigation along a preloaded route, back-to-start, etc. all work without any maps,

Absolutely, but those are just bread crumb trails and arrows.  For military use you'll need to know terrain, vegetation, contour, etc.

Absolutely, but those are just bread crumb trails and arrows.

And that is all that is needed in many cases. Speaking here as a person with vast experience using non-mapping gps receivers in navigation in unknown terrain.

For military use you'll need to know terrain, vegetation, contour, etc.

You'd be surprised how many non-mapping GPS devices are used today in the army, both handheld and vehicle-mounted. A skilled soldier can make very good use of a non-mapping gps. In fact, commercially available maps have often very little military value.

So while in some scenarios on-device maps can be useful, I strongly disagree that they are required for military use.

Would there be any other models cheaper than the fenix 6 for this? As long as I can plot from A to B on the watch, find my current grid for a check nav thats all I need. Can use an actual map for figuring out the terrian ie contours, relief etc. 

The Fenix 5 series has the long battery life that you may want for military use, without the maps. The 935 and 945 are almost identical to the f5 and F6 series respectively as well. There are other newer watches (eg. 245, vivoactive) that offer other newer features, but without the long battery life.

You would just need to change the positional format settings to MGRS to get navigational datapoints as grid references, rather than in dms.

It's been a long time since I served, but in my mind a GR from GPS and a paper map offer a lot better understanding of the terrain around you than a 1.4" digital screen ever could.

Greetings from Russia. We are killing these Fenixes form  a DEW cannon. Do not upset us, boring without worthy enemies. 

Use only mechanical watch and compass 

Who said anything about "required"?

You did. Maybe I misunderstood something, but here's a quote from your post:

"For military use you'll need to know terrain, vegetation, contour, etc."

And here's OP's question:

" will I need to download maps onto it or is that not necessary?"

and your answer:

"You'll have to download maps only if you deploy outside of the region from where the watch is purchased. "

This suggests that what OP wants cannot be done without maps, and that is not correct....

Ask any military service member which is preferred.  A detailed map or a bread crumb trail?

This is totally irrelevant. OP asked a very precise question, and I just didn't want him to get an impression, that without onboard maps he would not be able to do what he asked. Because some answers suggested that maps are required.

I'm fully aware what can be done without the assistance of GPS.

And I'm not talking about going without GPS, because that's not what OP asked about. I'm talking about using GPS without mapping capability.

I don't know which "army" you're referring too.  As stated earlier, I served 20 years in the US military and I have been a government contractor on Joint Base Lewis-McChord for the last 22 years.  So, I would be very surprised if you're suggesting this is the case in the US.

I'm not suggesting. I know for sure. Look at this:

https://en.wikipedia.org/wiki/Defense_Advanced_GPS_Receiver

Still widely used by American military, and adopted in many NATO countries. And this is just one example. Non-mapping GPS devices are very common.

Name one scenario where detailed maps would be detrimental

I didn't say detrimental. I said of little use. Especially civilian maps on a wrist-worn device. Sure, it won't hurt to have them, no matter how useless. I was merely pointing out that what OP wants does not require any mapping capability on the device.

another suggestion for map downloads. https://www.dcrainmaker.com/2019/08/how-to-installing-free-maps-on-your-garmin-fenix-5-plus-forerunner-945-or-marq-series-watch.html 

and don't forget to compare the navy exchange to the PX prices, they do different sales at different times- and will price match each other in addition to the civilian stores

You sure about that? I've found if the phone doesn't have a wifi or data connection, I can't make communicate via bluetooth with the watch. Initially I thought there was something wrong, but later read somewhere it was the case.

I’ve just double checked the Explore app on my iPhone and it works perfectly with my Fenix 6X Pro Solar when the phone is in airplane mode with WiFi off but Bluetooth still on. To be clear, this is the Explore app https://buy.garmin.com/en-GB/GB/p/614327 and not Garmin Connect Mobile (you do need to be online when you first add the watch to Explore, but after that no internet is required for Explore to sync with the watch).