  The search of secondary pulsations is carried out to understand the possible
relations among the known parameters of variables of the cluster, NGC 6866.
These pulsations arise due to the various ongoing physical phenomena of the
variables. Moreover, pulsations of the variables are identified through the
visual inspection of their frequency-amplitude distributions. A total of 18
variables among the 28 known variables are showing the secondary pulsation
modes. Furthermore, these pulsation modes do not occur for PV, EA, EB,
Elliptical and semi-regular. In addition, the field variables seem to be the
red-component-stars (RCS) for the studied cluster. The smoothness of the
frequency-amplitude curves, signal to noise ratio and the significant limits
are play major role for deciding the real peak or frequency values. We are not
rejected those amplitude peak of parabolic patterns, for which, the amplitude
is greater than then significant limit of variables. The weight of pulsation
frequencies is given to be 0.5 for non full cyclic variation but the amplitude
is greater than significant limit. Similarly, our present analysis does not
support the HADS characteristics of previous known HADS stars within stellar
cluster NGC 6866. We are also proposed to new correlation between the secondary
pulsation modes (depending frequencies) and the absolute magnitude of known
variables.
