  Radio-glaciological parameters from Moore's Bay, in the Ross Ice Shelf, have
been measured. The thickness of the ice shelf in Moore's Bay was measured from
reflection times of radio-frequency pulses propagating vertically through the
shelf and reflecting from the ocean, and is found to be $576\pm8$ m.
Introducing a baseline of 543$\pm$7 m between radio transmitter and receiver
allowed the computation of the basal reflection coefficient, $R$, separately
from englacial loss. The depth-averaged attenuation length of the ice column,
$<L >$ is shown to depend linearly on frequency. The best fit (95% confidence
level) is $<L(\nu) >= (460\pm20)-(180\pm40)\nu$ m (20 dB/km), for the
frequencies $\nu=$[0.100-0.850] GHz, assuming no reflection loss. The mean
electric-field reflection coefficient is $\sqrt{R}=0.82\pm0.07$ (-1.7 dB
reflection loss) across [0.100-0.850] GHz, and is used to correct the
attenuation length. Finally, the reflected power rotated into the orthogonal
antenna polarization is less than 5% below 0.400 GHz, compatible with air
propagation. The results imply that Moore's Bay serves as an appropriate medium
for the ARIANNA high energy neutrino detector.
