Should be the one at 1st/Glenn (seems most likely considering LTE at Amphi and 1st/Speedway, but not Grant/I-10, when referenced against https://network.sprint.com/AZ/Tucson/). Additional details in sponsor thread here http://s4gru.com/index.php?/topic/590-network-vision-site-map-phoenix-albuquerque-and-tucsonyuma-markets/?view=findpost&p=233305