The Radphi commissioning run of 1999 was presented several new conditions over what had been available during previous parasitic run periods. The first was the upgraded barrel detector that replaces the former recoil proton annulus with a full barrel calorimeter/veto. The second is a new level-2 trigger that enables running without an online charged-particle veto that was formerly limiting our rate capability. The third is the availability of photons up to 5.5GeV in energy. After setup and debugging for a period in parasitic mode with CLAS, we were granted control of the beam and were able during this period to raise the photon beam intensity to the level at which we expect to run. The measurements that were taken at that time are the subject of the following report. The expected and measured rates are in good agreement, showing that the detector is well reproduced in the Monte Carlo. Based upon the new measurements, the parameters that describe the trigger have been refined and improved estimates of the signal yield are presented as a function of beam intensity.