. In the early stages of evolution of supernovae, the shock front expands at a significant fraction of the speed of light. Effects due to the finite speed of propagation of the radio emission may therefore be important. We discuss the inclusion of travel-time delays in one particular model for the radio emission from SNR 1987A. we consider a spherically symmetric geometry and a time-dependent treatment of diffusive electron acceleration at the expanding shock. Analytic expressions for the flux density are presented, and we show that propagation delays are important at the initial switch-on of the emission, but not for its long-term evolution.