  The tentative Gravitational Wave Echo (GWE) at a frequency of about $72\,Hz$
has been recently claimed at $4.2\sigma$ significance level in the GW170817
event. GWEs can be used as a tool to study the characteristics of ultra-compact
stellar objects. Considering the final ultra-compact, post-merger object as a
strange star, the GWE frequency can be calculated. However, GWEs are observed
for only those compact stellar structures whose compactness lies in between
0.33 and 0.44. Alternatively, GWE can be obtained for those compact stars which
feature a photon sphere and compactness not crossing the Buchdahl's limit
radius $R_{B}=9/4M$. A photon sphere is a surface located at $R=3M$, $R$ being
the radius and $M$ is the total mass of the ultra-compact object. Recently
using the simplest MIT Bag model Equation of State (EoS) it has been reported
that strange stars can produce GWEs with frequencies of tens of kilohertz. In
view of this, for a comparative study, we have calculated the respective echo
frequencies associated with strange stars by considering three models of
strange star EoSs, viz., MIT bag model, linear and polytropic EoSs \cite{JB}.
We found that, not being too stiff the polytropic EoS can not emit GWE, whereas
the MIT Bag model and the linear EoSs can emit GWEs at a frequency range of
about tens of kilohertz. Also, GWE frequency increases with the increase in
values of bag constant $B$ and decreases with the increasing values of linear
constant $b$. So a model-dependent nature of GWE frequencies is observed.
