I'm trying to get a handle on how to decode WSR-88D data as found on the
NWS gateway services site:
http://www.nws.noaa.gov/tg/dataprod.html

Here's a description of directories:
http://www.nws.noaa.gov/tg/radfiles.html

Here's the root:
ftp://tgftp.nws.noaa.gov/SL.us008001/DF.of/DC.radar/

I found the ICDs that describe most of the data format he
http://www.osf.noaa.gov/ssb/cm/icd_downloads.asp

Specifically, I'm looking at 2620001F/ICD for the RPG to Class 1 User.

The problem I'm running into is that the first 30 bytes of the header
are documented. There seems to be a 21-byte WMO header which I can't
find documentation on. Here's the first 21-bytes:
SDUS54 KHUN 141532

Here's the other 9 bytes:
N0RHTX


Can someone here point me to some documentation that details this data?
If you know of any resources that might be of assistance I'd appreciate
you pointing those out.