Shapiro time delay is caused by refraction. Gravitational time dilation does not exist.
' The Shapiro time delay effect, or gravitational time delay effect, is one of the four classic Solar System tests of general relativity . Radar signals passing near a massive object take slightly longer to travel to a target and longer to return than they would if the mass of the object were not present. The time delay is caused by time dilation , which increases the time it takes light to travel a given distance from the perspective of an outside observer. [...] ' Throughout this article discussing the time delay, Shapiro uses c as the speed of light and calculates the time delay of the passage of light waves or rays over finite coordinate distance according to a Schwarzschild solution to the Einstein field equations .'- Wikipedia And, just like Pound and Rebka, completely ignores refraction. Which makes his whole calculation wrong, because he does not understand basic physics, ...