Ask Slashdot: 4G Networking Advice For Large Outdoor Festival?

New submitter xanadu113 writes "I help out with a large outdoor festival each year (Seattle Hempfest), and we use 4G hotspots on-site for our internet needs. Due to being at the bottom of the hill (in Myrtle Edwards park in downtown Seattle, WA right on the sound), we have problems with loss of signal, bandwidth switching (going between 4G/3G/2G, etc.). As wireless internet is our only option on site, we need to do something about improving the signals. What would be the best way to do a site survey of the 4G signals to select the best locations for hotspots, as well as the best carrier to use? We need potentially up to 10 devices per hotspot, and up to 10 hotspots or so. Also, would putting up a 4G repeater be a good option to solve this problem?"