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19990716: NOAAPORT and LDM?



>From: Chris Herbster <address@hidden>
>Organization: Embry-Riddle Aeronautical Univ.
>Keywords: 199907161239.GAA25211 NOAAPORT LDM

Chris,

>We have a C band antenna (13' dish) from an old satellite data feed here
>at Embry-Riddle Aeronautical University.  We were thinking of moving to
>a NOAAPORT data ingestion system as our campus Internet feeds are
>currently at a near saturated level and the IDD would put us over the
>limit.

Sounds like a decent plan.

>The first, and most important, question is, "Does the LDM software work
>for NOAAPORT?"  I expect this to be a "yes" but need to ask to be sure!

It depends on what you mean by this.  The way the NOAAPORT data is
currently being injected into the IDD relys on a data ingest system
that is produced by the SSEC at the University of Wisconsin-Madison.
You could purchase a data ingest system from SSEC or one of the other
converns that sell such units.

>What would be a suitable system to decode the data?

Given the above, I can tell you that a reasonable PC is enough to handle
the ingest and decoding functions.  By reasonable, I am referring to
a "current" kind of machine: 450 Mhz PC with at least 256 MB of RAM
and sufficient disk.

>Would a Linux-based Intel system be enough,

I would recommend Sun Solaris x86 instead of Linux for at least
the following reason: several sites running the LDM have noted that
Linux does not perform well with large product queues.  This has
to do with how Linux memory maps files (the LDM product queue is
memory mapped).

>or is a high-end RISC workstation needed?

Not really needed given that current PCs are quite capable.

>One
>workstation for each channel or can one workstation do more than one
>channel?

I can only give some information about the SSEC box; I don't know
enough about other commercial solutions to make any intelligent
comments.  Right now, the SSEC ingestor uses a special I/O card
to handle a single channel.  You need multiple of these cards
if you want to get multiple channels.

>Does each of the four data channels require a separate receiver?

A separate demodulator, yes.

>Can
>you suggest a vendor who might work with us to get the right hardware in
>place?

No, sorry.

>I've gotten a few price quotes for systems and most vendors seem to
>charge a lot of money for their software - since we have the dish
>already I was hoping to build the system ourselves using the Unidata
>software.

Once the ingestion system has gotten the data, the LDM can be used to
do things with it (a la IDD, and decoders run from pqact.conf files).
We have been playing with a special multiple channel card that can
be used to receive multiple NOAAPORT channels, but we do not have
a system (software, that is) that can be used at this time (the
future of this development is in uncertain at this time since we
lost our primary LDM developer that was working on it).

>As our campus network is upgraded over the next couple of years, I
>expect that we would be able to serve as a backup source for data for
>the rest of the Unidata community.

What do you have in mind?

>Any advice or general comments would be welcome!

Sorry I couldn't tell you that you can get everything you need from us...

>Thanks,
>
>Chris Herbster
>Dr. Christopher G. Herbster
>Assistant Professor
>Applied Aviation Sciences
>Embry-Riddle Aeronautical Univ. 
>600 S. Clyde Morris Blvd.
>Daytona Beach, FL 32114-3900
>
>904.226.6444 voice
>904.226.6012 fax

Tom Yoksas