WiFi - 5 GHz or 2.4 GHz ?
Most wifi routers or Access Points now offer a choice between the (old) 2.4 GHz or (newer) 5 GHz bands. The diference may prove to be important at specific venues so you may find the following information helpful if you have trouble using a wifi network for your diving Meet.
5 GHz
The advantages of this band are higher network speed and more channels (32) which combine to offer better performance at busy venues. So this sounds like a no-brainer! However the higher frequency comes at the cost of shorter signal range and being less able to penetrate physical obstructions. So if all your wifi devices have a direct line-of-sight to the router or AP and are not too far away, 5 GHz may be the right choice.
2.4 GHz
This band is slower and only has 11 or 13 channels (country dependent) so performance may degrade at a busy venue. However the lower frequency has the advantage of greater signal range and it is better able to penetrate physical obstructions.
Conclusions
If you cannot use wired network connections, then by all means try the 5 GHz band and if you then find you have some connection issues, particularly to 'backroom' devices, you will probably find the solution will be to use the 2.4 GHz band.