Hi to everyone!

I'm evaluating to buy an ultrasound instrument.
I'm not able to choice between SDT or UE.

Some one can help me to take the right way?
I work in a service company so our business is perform analysis and sell instrument.

Thank you
Andrea

You want an ultrasound instrument whose sound is related to the nature of the fault you are observing. Many instruments cannot do this. Even within a particular manufacturer, some instruments can and some can't. Here is how you can tell--obtain a spectrum using the headphone output and compare with the forcing frequency. For example, using an airborne module, point it at a transformer and see if you obtain 60 hz harmonics. Using a surface probe, obtain a reading on a machine with a well worn coupling or mechanical looseness. See if you get harmonics of shaft speed. If you have a bearing fault, you should obtain a clear display of the fault frequencies in the spectrum. If your spectra do not accurately reflect forcing frequencies, than the instrument sound quality will be poor and you will be unable to distinguish faults from properly functioning machines that simply produce elevated ultrasound.

What are your applications? Many of todays airborne ultrasound instruments can in fact perform most if not all applications. That is, bearing analysis, leak detection, electrical scanning of substations & switchgear for corona, tracking & arcing. However, as Testtech mentioned, some can do it better than others. For me, I would like to know what tasks you are wanting to accomplish and today of course the $24K question is "how much are you willing to spend"?
I would advise you to ask both of these companies to your site to demonstrate their products. The BLOGISPHERE is full of manufacturers reps disquised as technicians or neutral on-lookers suggesting one instrument over the other. You can contact me directly and I can advise you. In my training classes I have the several ultrasound instruments on-hand (UE, SDT, CSI, CTRl, DST).
You said that you are a service company and you sell instruments. First of all if your a pdm service company you need your instrument to talk to your database or integrate with your other support software. Both UE & SDT for instance are driver supported by companies such as DMSI to drive information to the Maintellegence System. Second, if you sell instruments then you should go after one of these companies to possibly represent them in your area.
One last thing is "ACCURACY & REPEATABILITY"!
If you can take your instrument and hold an alike instrument (make & model to the same make & model) touch a bearing or the face of the tone generator (signal generator) and get the same reading within a db or two, then they are repeatable and accurate enough. Unfortunately, ultrasound instruments today have a real problem with both accuracy & repeatability.
Jim Hall, President
Ultra-Sound Technologies
"Vendor-Neutral"
U.S. Disabled Vet Owned Business
www.ultra-soundtech.com

Guys, this site is not a site to evaluate a piece of equipment, sales are left up to you the end-user to observe and evaluate at your site. This forum is a site to discuss applications, methodology, and general discussions. Call the manufacturers of the equipment you are interested in and have that company send a representative or rent or borrow a piece of equipment to determine the usefulness for your applications.
As I mentioned before if you email me (I am vendor-neutral) I will help you after I know the applications, industry, your other pdm equipment and what you want to accomplish.
Jim Hall (co-editor UPTIME Magazine "Ultrasound")
and President of Ultra-Sound Technologies (training company)
jim.hall@ultra-soundtech.com