Dave

I don't know, because I've never used a Geko, but I think it has the more sophisticated, helical, antenna, and the way it's held matters less.

John

Geko is best held horizontally. I usually have mine clipped onto the shoulder strap of my ruacksack - right up on top of the shoulder.

I have a Geko 101 and I try to carry it horizontally but no matter how I try I always forget. It doesn't seem to matter as I've only ever had a problem with it once and that was definitely due to operator error.

I have a Geko 201, carried on a rucksack strap but it tends to be vertical or horizontal on its side (if that makes sense) depending which sac. Never noticed any problem either way in general use. The only times I've ever struggles with signal are places like dense woodland or close in under a cliff/gully where you'd expect that with most GPS units anyway.