Hi Sameer,
We see this behaviour on the X channel on our filterless iProbe if you don’t
use the 2H stop-filter on the X channel (we specified this option at
purchase time so we could do 6Li experiments).
You can make it go away by using the RF filter, or by reducing the lock power
to lower than -15 dB or so. It doesn’t seem to matter too much what
frequency the X channel is tuned to.
If reducing the lock power isn’t enough to make it go away, then the
brute force option is turn the lock off and unplug the 2H channel e.g. on
the back of the preamp.
Thanks
Geoff
> From: main_at_ammrl.groups.io <main_at_ammrl.groups.io> On Behalf Of Spin-Doc
> Sent: Thursday, May 30, 2024 8:03 AM
> To: main_at_ammrl.groups.io
> Subject: [External] Re: [AMMRL] Frequency ocillation in wobb curve on Prodigy TCI probe
You could try to swap the SGUs to see whether that is the culprit.
Cheers
Bert
-> Sent via mobile <-
Spin-Doc
Magnetic resonance equipment, service, training & more
Dr. rer. nat. Bert Heise
Owner, applications scientist
Kiefernweg 13
58239 Schwerte
Germany
Web: http://www.spin-doc.net
Mail: bert.heise_at_spin-doc.net<mailto:bert.heise_at_spin-doc.net>
Phone: +49-171-5135315
Representing MestreLab, Stelar & Barthel HF
Am 30.05.2024 um 03:00 schrieb Bob Berno
Hi Ken,
I think Sameer may be on to something.
When I saw your WOBB curve, it reminded me of the WOBB I saw on a BBO probe
when we did not have the 2H-stop filter on the broadband preamp. So, in my
case I was seeing the lock signal making its way through to the broadband
preamp.
However, you have a TCI Prodigy cryoprobe. So you should have a dedicated
cold 13C preamp with a narrow bandpass filter. You should not be seeing any
2H signal on the 13C channel.
What happens if you turn the lock off? Using the “lock off”
command might not be enough, you may need to turn the lock power all the way
down too.
If the oscillation goes away, that you are getting interference from the 2H-channel.
Good luck,
Bob.
> From: main_at_ammrl.groups.io On Behalf Of Sameer Al-Abdul-Wahid via groups.io
> Sent: May 29, 2024 5:54 PM
> To: main_at_ammrl.groups.io<mailto:main_at_ammrl.groups.io>
> Subject: Re: [AMMRL] Frequency ocillation in wobb curve on Prodigy TCI probe
Hi Ken and AMMRL,
We recently observed oscillations in the WOBB curve of all channels on a solids
AV II instrument, which we ultimately traced back to a failed LT1083CP
regulator on the 12V rail of the PSM3. The rail was outputting ~20V instead of
12V. Frustratingly, the PSM3 LEDs were all lit even though the regulator was
faulty. Replacing the regulator fixed the problem.
However, since your issue is only on the 13C channel, I suspect our similar
symptoms have different causes. This may be a long shot, but if the calibrated
13C pulse width is longer, perhaps there’s an issue in the HPPR slice?
Best,
Sameer
--
Sameer Al-Abdul-Wahid, Ph.D. | Manager
Nuclear Magnetic Resonance Centre | University of Guelph
519-824-4120 Ext. 58914 | s.wahid_at_uoguelph.ca
http://nmr.uoguelph.ca/
________________________________
> From: main_at_ammrl.groups.io on behalf of Kenneth Sharp-Knott via groups.io
> Sent: Wednesday, May 29, 2024 3:19 PM
> To: ammrl_at_groups.io
> Subject: [AMMRL] Frequency ocillation in wobb curve on Prodigy TCI probe
I'm experiencing what looks like a frequency oscillation through the C13 wobb
dip. I don't see evidence of it in 1H or 2H wobb curves.
I was it was worse yesterday to the point that 13C sensitivity was significantly
reduced, which is what brought it to my attention. After a console reboot,
computer restart, cf, etc... Sensitivity seems to be about normal, but I'm
still seeing this oscillation.
Has anyone seen anything like this?
Ken Sharp-Knott
Manager of Analytical Services and the NMR Facility
Department of Chemistry
Virginia Tech
(540)267-6502 (Cell)
(540)231-0885 (Office)
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#1297): https://urldefense.com/v3/__https://ammrl.groups=
.io/g/main/message/1297__;!!PvDODwlR4mBZyAb0!U05yub5pvbtGfbXq_6EO3-RduT8Aga=
QFoEAVNcjy7KcT6u6KcFET4bR2WXRXvfYnO03zDFhGIcbBfxnC6X3aww$
Mute This Topic: https://urldefense.com/v3/__https://groups.io/mt/106375463=
/7559972__;!!PvDODwlR4mBZyAb0!U05yub5pvbtGfbXq_6EO3-RduT8AgaQFoEAVNcjy7KcT6=
u6KcFET4bR2WXRXvfYnO03zDFhGIcbBfxk4dXAsAA$
Group Owner: main+owner_at_ammrl.groups.io
-=-=-=-=-=-=-=-=-=-=-=-
Received on Thu May 30 2024 - 02:47:33 MST