Results are reported from a search for fluctuations in the cosmic microwave background radiation (CMBR) on angular scales of 2 deg or greater at 10.4 GHz. Data obtained over a 2-yr period at Teide Observatory at Tenerife are presented in a map and briefly characterized. At high Galactic latitudes, signals with rms Delta-T/T of about 0.000037 are detected in beams of 5-8 deg when the system sensitivity is of order 0.00001. Assuming the signals are from intrinsic CMBR fluctuations (z = about 1000), these observations appear to rule out ordinary adiabatic cosmological scenarios comprising baryonic matter at density less than the closure density of the universe.