Assuming that all of your pulses (both the hard pulses and shaped pulses) and everything are calibrated properly, it could be that at 600 MHz you are now at the cross-over point between extreme narrowing and spin-diffusion. What is the molecular weight of your compound, and what solvent are you using?

The easiest way to set up these experiemnts is with the selective panel, available from the "Spectrometer" menu. This will only work if you have a properly setup prosol table, however.

Assuming that all of your pulses (both the hard pulses and shaped pulses) and everything else are calibrated properly, it could be that at 600 MHz you are now at the cross-over point between extreme narrowing and spin-diffusion. What is the molecular weight of your compound, and what solvent are you using?

The easiest way to set up these experiemnts is with the selective panel, available from the "Spectrometer" menu. This will only work if you have a properly setup prosol table, however.

If you are at the cross-over point, a ROESY experiment may work.