Stationary receiver: http://www.einstein-online.info/imag...ler_static.gif

Moving receiver: http://www.einstein-online.info/imag...ector_blue.gif

"...the distances between subsequent pulses are not affected, but still there is a frequency shift: As the receiver moves towards each pulse, the time until pulse and receiver meet up is shortened. In this particular animation, which has the receiver moving towards the source at one third the speed of the pulses themselves, four pulses are received in the time it takes the source to emit three pulses." http://www.einstein-online.info/spotlights/doppler.html

The speed of the light pulses relative to both the source and the stationary receiver is c; their speed relative to the moving receiver is (4/3)c, in violation of Einstein's relativity.

Pentcho Valev