The following information obtained from UNAVCO's online DOI system:
(https://www.unavco.org/data/doi/search/search.html)

PBO GPS Network - P778-MonteagleTN_2008 P.S.
Start: 18-Apr-2008
End: 18-Dec-2019
UNAVCO Community, 2008, PBO GPS Network - P778-MonteagleTN_2008 P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5VQ30PX