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We present measurements of the spectroscopic coherence time, T2* of a Nb-AlOx-Nb dc SQUID phase qubit. T2* is calculated from the spectroscopic width of the |0rang to |1rang transition measured at 25 mK. We find that T2*increases at higher transition frequencies corresponding to measurements deeper in the potential well. The measured are consistent with root mean square current noise saturating at 4 nA.