Hi all,
We use ampmode='dddp' on all our instruments without problem.
Not having 'dddp' however does cause serious problems as the deterium
amplifier (channel 4) noise leaks into the receiver channel reducing
spectral quality. "p" allows programmable performance on the 4th
channel. We either have to turn off the 4th channel amp when not in
use or have ampmode properly set.
ampmode (as per the command parameter manual) sets the "default" mode
for the amp allowing control and gating. Destroying this parameter
should result in the same default function of the amp and presumably
no change in performance.
Another method would be to swap the function of channels 2 and 3 and
see if you get 15N decoupling properly when using the channel 2 (i.e.
biopack 13C amp) instead of the channel 3 amp.
This can be done easily using the "channel" command, e.g. channel=
1,3,2,4 and setting the dn='N15', dof, dpwr, etc. pararmeters to
proper nitrogen settings on e.g. gChsqc.
If you only get consistent dependable decoupling on channel 3 you know
where the problem is.
** This sounds like the problems we were having one time. Turned out
it was a flaky/intermittent waveform board.
If dmm2='ccp' and we used shaped decoupling (like biopacks default
wurst15N.DEC) we'd sometimes get decoupling and sometimes not.
If we switched to hardwired decoupling (e.g. dmm2='ccg' and set to
garp parameters) we'd be fine consistently.
Best wishes,
Ryan
------------------------------------------------------------------------------------
Ryan T. McKay, Ph.D. - Scientific Director
NANUC - Canada's National High Field NMR Centre
Room 105 Email: ryan_at_nanuc.ca
NANUC Bld. Phone: (780) 492-2700
University of Alberta Fax: (780) 492-9174
Edmonton, Alberta Cell: (780) 920-8871
Canada T6G 2E1 AIM: ryanmckaynmr
http://www.nanuc.ca
------------------------------------------------------------------------------------
Deryck Webb - NMR Technologist
NANUC - Canada's National High Field NMR Centre
Room 103 Email: deryck_at_nanuc.ca
NANUC Bldg. Phone: (780) 707-0857
University of Alberta Fax: (780) 492-9174
Edmonton, Alberta Cell: (780) 707-0857
Canada T6G 2E1 AIM: derycknmr
http://www.nanuc.ca
Received on Fri Feb 13 2009 - 12:06:59 MST