  We report the first attempt to observe the secondary eclipse of a transiting
extra-solar planet at radio wavelengths. We observed HD 189733 b with the
Robert C. Byrd Green Bank Telescope of the NRAO over about 5.5 hours before,
during and after secondary eclipse, at frequencies of 307 - 347 MHz. In this
frequency range, we determine the 3-sigma upper limit to the flux density to be
81 mJy. The data are consistent with no eclipse or a marginal reduction in flux
at the time of secondary eclipse in all subsets of our bandwidth; the strongest
signal is an apparent eclipse at the 2-sigma level in the 335.2 - 339.3 MHz
region. Our observed upper limit is close to theoretical predictions of the
flux density of cyclotron-maser radiation from the planet.
