The proof that property owners are underpaid for their cell tower leases is reflected in revenue derived from cell-tower companies. In 2012, the largest cell-tower companies generated over $2 billion in yearly revenue on average, from simply subletting properties like yours.
Property owners have a choice to be underpaid for their land or, arm themselves with information that allows them to get fair value for the use of your land. Not only do you have options, you have bargaining power. For property owners, an increase of a few hundred dollars in cell tower rent per month can mean hundreds of thousands of dollars in additional revenue over the life of your lease.
Remember the telecom companies have experts working for them, shouldn’t you?