  We analyze the response of the gravitational wave detector to a scalar
massive plane gravitational wave. We give the compact form of the response and
discuss its angular and frequency characteristics. The derivations is carried
out in the conformal and the synchronous gauges and the equivalence of the two
approaches is shown. In the case of the massive Brans-Dicke theory we solve the
linearized vacuum field equations in the two gauges as well.
