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

Northern Basin and Range GPS Network - EGAN-Egan P.S.
Start: 25-Mar-1997
End: 14-Nov-2022
UNAVCO Community, Davis, James, 1998, Northern Basin and Range GPS Network - EGAN-Egan P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5PK0DHK

Northern Basin and Range GPS Network - EGAN-Egan P.S.
Start: 15-Jun-2005
End: 14-Nov-2022
UNAVCO Community, 1998, Northern Basin and Range GPS Network - EGAN-Egan P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5F47MH2

Northern Basin and Range GPS Network - EGAN-Egan P.S.
Start: 25-Mar-1997
End: 15-Jun-2005
Davis, James, 1998, Northern Basin and Range GPS Network - EGAN-Egan P.S., UNAVCO, GPS/GNSS Observations Dataset, 
https://doi.org/10.7283/T5JW8C7G