Simultaneous scintillation data from the ATS-6 Radio Beacon Experiments for signals at 40, 140, and 360 MHz offer the opportunity to study the frequency dependence of the scintillation phenomenon. Using these data variations of the spectral index, correlation coefficient, and the correlation interval are investigated. It is found that for weak scintillations, the spectral indices lie between 1.5 and 1.7. When the scintillation is strong, the spectral indices vary from about 1.4 to 0.7. The correlation coefficients are found to decrease for increasing scintillation level. The interesting behavior of the correlation intervals as functions of signal frequency is also discussed. The observational results are compared with theoretical predictions.