My airport express is pretty reliable, works best when you have line of sight, sometimes I put it on top of one of the PA cabs in a busy venue with lots of bodies and I’m somewhere near the back of the room
Apple Airport Extreme, (one of the older square ones)I think one of the last generation of those, set for 5Ghz, SSID hidden, and placed up high above humans. I’ve gotten good reception at a distance of 100Ft with audience of about 400 with that unit. Only very rarely loses connection when I’m at the back of the room, and when I sit down (after lots of standing). Hope that helps!
In a field, I’ve had probably 250 – 300m from an Airport Express, mounted high up, not that I needed that distance, just seeing how far I could get.
Then again, I’ve had it drop out repeatedly at only about 3m in an over-crowded pub with lots of other wifi in use. But repositioning it a bit seemed to sort that.