Sorry Chris. I respectfully have to disagree here.
Farmtalk, here is what you need to do. (Info obtained from the TRIAL SUPPORT FORUM):
1) Download the L3 data files from the NCDC website:http://hurricane.ncdc.noaa.gov/pls/plha
Don't select the "Click here to Order UNTARRED contents...". You'll eventually get a notification email with a link to the archived data file(s). Download the file to your local machine.
2) Download the command line utility program named NCDCtoRV3: Please go to the Owner's board to get more information on the NCDCtoRV3 utility app: http://www.grlevelx.com/owners/index.php
Place it on your Windows path or in the directory that you'll use for keeping your archived data.
3) Start a Windows command line session. Select Start->Run, type in "cmd", hit enter. Change to the directory containing the NCDC archive file.
4) Run the program and give it the name of the NCDC archive file, eg. "ncdctorv3 7000KFFC20080104.tar.z".
You'll end up with over one hundred individual .rv3 files, one for each radar volume in the archive. Simply drag and drop those rv3 files on GRLevel3 to view them.
Hope this helps!