  We present a BIMA image of the supernova remnant G21.5-0.9 at 94 GHz with
angular resolution 8.6" x 4.5". On scales larger than our synthesized beam, our
results do not indicate any radial or local variations in the acceleration or
synchrotron loss processes for the relativistic particles emitting at radio
wavelengths. However, the FWHM size of the radio remnant is significantly
greater than that of the X-ray remnant. Either any low-frequency spectral break
is distributed across the remnant, or more probably the break frequency is in
fact higher than ~100 GHz.
