The results of a survey of planetary nebulae for radio emission at 430 MHz are reported. The observations covered a declination range from - 2" to +38" and were made with the 1000-foot radio telescope at the Arecibo Ionospheric Observatory. A few observations at 611 and 195 MHz are also reported. Twenty-six per cent of the observed nebulae gave measurable radio signals. The spectra of some individual nebulae are discussed. NGC 6781 and A48 seem to have non-thermal spectra. An attempt was made to derive the interstellar extinction at H for some nebulae, by comparing the measured H fluxes (uncorrected for interstellar extinction) with the H fluxes predicted from the radio observations. The results seem to be satisfactory. Electron temperatures for NGC 6572, NGC 6720, and NGC 6853 are derived using the optically thick part of their radio spectra.