( catalog RV UMa ) is one of the RRab stars showing regular large amplitude light curve modulation .
Extended photoelectric observations of ( catalog RV UMa ) obtained at the Konkoly Observatory were published by Kanyó ( 9 ) .
The analysis of the data was published by Kovács ( 11 ) .
After detecting an error in the reduction procedure of the published Konkoly data , corrected photometric data are presented with additional , previously unpublished measurements .

The reanalysis of the combination of the corrected Konkoly data supplemented with Preston & Spinrad ’ s ( 1967 ) observations has led to the discovery that the adequate mathematical model of the light curve is , in fact , a quintuplet , instead of a triplet frequency solution .
This finding has crucial importance in the interpretation of the Blazhko phenomenon , as triplet ( doublet ) is the preferred structure in the resonance models , quintuplet in the magnetic models .

Period changes of both the pulsation and the modulation light variations of ( catalog RV UMa ) have been detected based on its century long photometric observations .
An overall anticorrelation between the pulsation and the modulation period changes can be defined with dP _ { Bl } / dP _ { 0 } = -8.6 \times 10 ^ { 4 } gradient , i.e. , the modulation period is longer if the pulsation period is shorter .
Between 1946 and 1975 the pulsation and modulation periods showed , however , parallel changes , which points to that there is no strict relation between the changes in the periods of the pulsation and the modulation .