I've found good advices to get started just on the project site (I'm no expert but I got it working without spending a lot)
Discussion
What hardware did you get?
I got a pair of these (heltec V3) and an antenna (a cheap one from Amazon)
they're provided with their own antennas, I got a bigger one for the "home station"
and this is the case I made with a spare box I had (very lucky because it can hook it to my backpack!)
I also included a spare GPS unit I had lying in a drawer
Which supplemental antenna?
This one! Perfect for my experiments