  We present first results from a dark photon dark matter search in the mass
range from 44 to 52 $\mu{\rm eV}$ ($10.7 - 12.5\,{\rm GHz}$) using a
room-temperature dish antenna setup called GigaBREAD. Dark photon dark matter
converts to ordinary photons on a cylindrical metallic emission surface with
area $0.5\,{\rm m}^2$ and is focused by a novel parabolic reflector onto a horn
antenna. Signals are read out with a low-noise receiver system. A first data
taking run with 24 days of data does not show evidence for dark photon dark
matter in this mass range, excluding dark photon - photon mixing parameters
$\chi \gtrsim 10^{-12}$ in this range at 90% confidence level. This surpasses
existing constraints by about two orders of magnitude and is the most stringent
bound on dark photons in this range below 49 $\mu$eV.
