An exempt organization is not taxed on its income from an activity that is substantially related to the charitable, educational, or other purpose that is the basis for the organization's exemption. Such income is exempt even if the activity is a trade or business.
Generally, income derived from the rental of real property and incidental personal property is excluded from unrelated business income and hence, is not taxable. However, there are certain situations in which rental income may be unrelated business taxable income
¡ if a church rents out property on which there is debt outstanding (for example, a mortgage note), the rental income may constitute unrelated debt-financed income subject to UBIT. (However, if a church or convention or association of churches acquires debt-financed land for use in its exempt purposes within 15 years of the time of acquisition, then income from the rental of the land may not constitute unrelated business income.),
¡ if personal services are rendered in connection with the rental, then the income may be unrelated business taxable income, or
¡ if a church charges for the use of the parking lot, the income may be unrelated business taxable income.
You can review the link below specific to your case-
Regarding sale of rights for a lumpsum settlement-
In general, rents from real property, royalties, capital gains, and interest and dividends
are not subject to the unrelated business income tax
unless financed with borrowed money.
So the sale of rights to cell tower (being a capital asset) will not be subject to tax.
Let me know if you have any question.
Please note: This advice is provided with the understanding that all the relevant facts have been provided by you. Any change in facts might affect the advice given and hence may not be relied on in such cases.