5.1 RF Tuning

 

The RF tuning is performed by centering the dip of the wobble curve on the screen through turning the tuning and matching rods at the bottom of the probe. The rods for the 1 H channel are labeled yellow, the rods for the 13 C channel are labeled blue. The tuning bandwidth of the 13 C channel is equal to a few MHz. The 2 H lock channel is fixed, i.e., no external matching and tuning adjustment is necessary.

 

Always tune the probe while the sample is spinning. When tuning the probe pay attention to the wobble curve. If modulations are superimposed on the wobble curve, this is usually a sign that the sample spinning is not stable. Adjusting the drive and bearing pressures or restarting the spinner can stabilize the spinning. If problems persist, repack the sample.