By applying a spin-echo double-resonance technique to 31P and 27Al in AlPO4-5, one can detect that 31P is coupled to 27Al. Although the pulse sequence used resembles that of the SEDOR expt., it actually differs and the mechanism of the phenomena seems to differ from the mechanism of the original SEDOR expt. The expt. was tried on 29Si and 27Al in the zeolites NaA and NaY. For NaA, there is a small but definite effect of Al irradn. on the 29Si spin-echo intensity. For NaY, the signal-to-noise ratio is too small to observe an effect.