We analyze observations of the Earth's nonthermal continuum emission made between 30 and 80 kHz with the radio receiver on board ISEE 3 when the spacecraft was in the distant magnetotail and crossed the magnetopause many times, and when the magnetosheath plasma density varied over a wide range. We correct for quasi-thermal noise by calculating its magntidude from measured plasma parameters and subtracting it from the data. The intensity and the anisotropy of the nonthermal continuum radiation field are always found to be larger in the lobes than in the magnetosheath; i.e., the apparent source is less bright and its size is larger when observed from the magnetosheath. These properties sometimes extend to frequencies as high as 80 kHz. We interpret the radiation as arising from a source located at or near the plasmapause, much closer to Earth than the spacecraft distance of ≂200 RE. We suggest that the observed variations across the magnetopause of the intensity and anisotropy (apparent size) can be understood by taking into account the facts that the magnetotail is a plasma waveguide whose walls are sometimes rough and leaky and that there are density fluctuations in the magnetosheath. The efficiency with which the continuum power at 30 kHz is collected in the near-Earth regions and ducted toward the distant tail is a strong, increasing function of the magnetosheath plasma frequency fp,msh. The percentage of that power which travels in the magnetosheath decreases with increasing fp,msh. There is no need for a radiation source in the deep magnetotail regions to account for the nearly isotropic radiation observed in some locations and at some frequencies. In the few cases in which we could derive an upper limit to the spectral density due to a local source, it was less than 10 to 20% of that of quasi-thermal noise at frequencies >1.7¿fp,msh. ¿ American Geophysical Union 1990