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[Datastream #DLO-642787]: GRB feed...how do we get it?

Hi Gilbert,

First, I drove this into our inquiry tracking system.

re:
> I hope both of you are doing well!

We are both OK, thanks.  And you?

re:
> We would like to get the GRB feed on
> our own at Allisonhouse...GOES-16 only...using our own equipment. We
> have so far:
> 
> A 2.5 meter dish, Norsat 3120 LNB expected to be installed if we can do it
> Novra S300N receiver
> 
> One server with soon to be two fast processors and tons of memory
> 
> I am wondering if:
> 
> 1. Our dish is big enough to get it reliably...

I seriously doubt it.  There is a NOAA map that shows the recommended
size of receiving dishes as a function of location, and
the smallest dish shown for both GOES-16 and -17 is 3.8m
and that is for an area that is more directly under the spacecraft.

re:
> 2. Will a Novra S300N work to get the data?

No.  The only similarity between the GRB and NOAAPort is
they both use DVBS2.  After that, they are completely different.

That being said, Novra now lists a receiver (not the S300N) that they
claim can be used for GRB downlinks.

The following link may be helpful in answering some of your questions:

https://www.goes-r.gov/downloads/resources/documents/GOES-RSeriesDataBook.pdf

This page contains the following snippet that should be enlightening:

"GRB uses two digital streams, each at 15.5 Mbps, compared to the GVAR
standard of a single 2.11 Mbps stream. A dual polarization approach is 
used to accommodate the 31 Mbps data rate within  a  frequency  bandwidth 
 of  9.8  or  10.9  MHz  per  polarization,  using  a  standard  downlink 
modulation at 1686.6 MHz (L-band). GRB is able to deliver a full disk image 
in either five, ten,or fifteen minutes, depending on mode, compared to GVAR’s 
thirty minutes.

The  GRB  processed  instrument  data is  packetized  
compliant  with  Consultative  Committee  for Space Data Systems (CCSDS) 
Standard 133.0-B-l and utilizes lossless data compression to fit within  
allocated  bandwidth.  Data  blocking  and  accompanying  header  metadata  
are  used  to minimize the risk of data loss due to link errors and allow 
for user verification of data integrity."

re:
> 3. Can we run two instances of the LDM on the sane server with a third
>    NIC card on eth2 to get the feed?

This might be possible, but the overhead of the software that creates products
from the GRB uses quite a bit of a machine by itself (lots of Python processes),
so we wouldn't recommend it.

re:
> 4. What are you using to get the feed?

We are using:

4.5m Challenger dish (SSEC uses a 7.3m dish!)
Quorum GRB 200 receiver
Quorum 100 and 200 LNB (we have downlinks for both GOES-16 and -17)
CSPP-GEO software (free from SSEC/CIMSS)

Our GOES-17 installation cost on the order of $125K.  It is in
quite another league from NOAAPort ingest systems.  With the
entrance of Novra into the market, the price to put together a
reliable downlink should have dropped, but I don't know to what
level.

Asides:

The dish we are using for GOES-17 ingestion was originally
the one we were using for GOES-16, but we had to re-purpose the
dish since there was fairly strong TI being experienced when the
dish was pointed at GOES-16.  Re-pointing it at GOES-17 pretty much
eliminated the TI that plagued our GOES-16 efforts.

We are now using a 3.8m dish for our GOES-16 ingest, but the C/N
we can get with it is not what we would like.  The low C/Ns are
being caused by a) the size of the dish and b) the location of
the dish (outside of the cafeteria at FL-2) includes tree tops
in the line of sight from the dish to GOES-16, and throughout
the late spring till early fall, the leaves on the trees causes
a drop of C/N to about the minimum level needed for ingest.  We
are looking for a different site where we can relocate our GOES-16
downlink.

There are people in the community that are doing GOES-16 downlink
and ingest "on the cheap".  Ray Weber is one who comes to mind as
we have had email exchanges with him about his setup.  Mike and
I have been eager to try out setting up a downlink "on the cheap",
but the Covid-19 pandemic put that sort of activity on hold for
the foreseeable future (sigh).

Cheers,

Tom
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Ticket Details
===================
Ticket ID: DLO-642787
Department: Support Datastream
Priority: Normal
Status: Closed
===================
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