We have a AC250 with a Tecmag interface (MacSpect3). We need
to use the decoupler instead of the transmitter for a certain experiment
because of a significant droop in transmitter power. It seems that the
decoupler power output is much more stable. However, we found that the
phase of the spectrum is non-reproducible when the decoupler is used.
(I.e.: we acquire a 1D spectrum, phase it to absorption, repeat the acquisition
with the same set of parameters 30 seconds to 5 minutes later, phase the
spectrum again, and the phase of the last spectrum would be random).
That, of course, completely screws up acquisition of more than one
transient and 2D experiments.
The two scenarios we are looking into are: 1) The original Bruker
decoupler delivers random phase; 2) there is something about the Tecmag
interface that makes the decoupler and the receiver work in a
non-synchronized way. However, at the time we cannot point out the
problem or even localize it.
Has anyone ever come accross a similar problem while doing inverse mode
experiments on similar instrumentation ? Any suggestions will be very
much appreciated.
--Konstantin Momot Group of C. S. Johnson, Jr., UNC Chapel Hill
Ph.: (919)-962-7576 momot@indy95.chem.unc.edu http://www.u.arizona.edu/~momot/research.html