Analysis of previous experimental works concerning verification of the relativistic Doppler effect is performed. New results have been obtained in the modern Ives experiment with the canal rays. The beam of excited hydrogen atoms is produced by accelerating H+2 ions with voltages from 150 keV up to 2.000 keV. There is a systematic deviation in the results obtained from those according to the special theory of relativity. The classical approach to understand experimental data is offered. Both theories are compared.