GOES 16 GRB downlink vs GVAR

Discussion in 'Free To Air (FTA) Discussion' started by GOES 12 GVAR user, Sep 17, 2017.

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  1. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    GOES instruments are designed to sense things just like those in Oklahoma. That's one of the missions of GOES.
    There are specific divisions of NOAA that do monitor the fire conditions. It was one reason that the satellite is designed the way it is.

    A link to other products the GOES can produce.
     
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  2. KWX

    KWX SatelliteGuys Family

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    That's some great news!!!
     
  3. KWX

    KWX SatelliteGuys Family

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    Hopefully I'll get some additional time this week to work some more on the LINUX app that I used to get the signal status and add streaming capabilities to send BB Frames to CSPP. Likely ensuring the BBF are synced before re-transmission will be the challenge for me. lol
     
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  4. N6BY

    N6BY Geek
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    weather01089 received a reply from Digital Devices last week. They told us that the DD card switches AGC (automatic gain) modes after a cable pull.

    There are 2 gain modes, NF and IIP3. After pulling the cable and reconnecting, the card goes into NF mode which is when streaming starts.

    They added a Windows registry key which is supposed to allow us to force the card into NF mode. But weather01089 tried it and it didn't help.

    My best guess is that streamreader.dll is somehow overriding the Windows registry setting. CrazyCat (author of streamreader) claims it doesn't, but I have doubts. So I am currently in the process of writing my own code to eliminate the need for streamreader.
     
  5. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    Question,
    Any recommendations for stream recording software?
    TBS recorder/IP tool don't work with the omnicom card. Got the driver installed but have no type of software to analyze it with, need some ideas.
    Has to work on Win XP.
    Otherwise have to go to option 2...
     
  6. N6BY

    N6BY Geek
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    EBS Pro can record from most DVB cards (and it is currently 'freeware'). Since it uses streamreader.dll you need to edit the streamreader.ini file and uncomment the line "NoPidFilter=1". Another possibility is TSReader, but the free version doesn't allow recording.

    And there are other programs you might want to try, like 'ProgDVB', 'SmartDVB' and 'DVB Dream'.

    Anyway, if you can get a recording from the card I can analyze it and see if it looks like it has valid BB Frames.
     
  7. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    Thanks again Brett,
    I installed EBS pro, installed fine.
    Got it set up and now I need to set up again and see what I've got.
    EBS Pro directly supports the omnicom card so I should have the best results I can get with it.
    I assume that when it records, it records it as it sees it. As I don't see a method of selecting TS or GS as in the TBS software.
     
  8. N6BY

    N6BY Geek
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    That is a good question. I don't know what will happen with the Omicom card. My TBS6983 card with GRBStreamer automatically selects TS or GS depending on the MAType-1 byte (the first byte of the BB Header). The Digital Devices Cine V7A also looks at the MAType-1 byte, but if it detects BB Frames it encloses them in a series of 188 byte TS packets.

    But I have never tried an Omicom card. Be sure to uncomment the line "NoPidFilter=1" in the streamreader.ini file. And then reboot your system to ensure that the change takes effect.

    If EBSPro gets confused by the GS stream then let me know and I will send you a version of GRBStreamer that records to a file.
     
  9. Micanopy Mike

    Micanopy Mike New Member

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    I have been following the GOES GRB thread with great interest as I am interested in downlinking and displaying the near real-time animated GRB imagery. I noted the comment about being interested in downlinking the GOES West GVAR imagery. I happen to
    have a GVAR modem and a companion bit-stream synchronizer that was used for downlinking GOES-East GVAR a few years ago.
    I am guessing that they are suitable for the current GOES-West GVAR signal. Both of these items and their manuals are available
    if there is any interest in them. They have been sitting on a shelf in my workshop building for some years but were both functional when they were taken out of service. I am located in Micanopy, FL just 8 miles south of Gainesville, FL.

    As a side note, I am a rank-newbie at using forums like this one and totally unfamiliar with how to make them work. It took me a while to find out where to click to post a response to this long-running GRB / GVAR thread. I am currently working on RX and display of the GOES-East EMWIN imagery and have what I think is a pretty good signal level from my dish. The GRB signal also looks pretty strong as well but this photo is from a linear polarity feed and the CP GRB signal is reduced by several dB. I am not sure if it is good enough to actually use at this low signal level. I'll try to post a photo from my spectrum analyzer of the signals but am not sure how to do that. I see a place to click on to "Upload a File". Is this where/how I post a photo to this thread? What are the file size requirements for posting my .jpg photos? I will take a chance and try to post something that is pretty low-res. The LHCP feed is a homebrew version. I used a CP patch feed and attached a 0.4 dB NF / 20 dB gain LNA followed by a 2 dB NF / 30 dB gain amp to send the signal thru the 100-ft of 1/2" Andrews Heliax hardline coax into my workshop. The GOES signal photo is from a Tektronix spectrum analyzer inside my shop building. I hope these photos are a suitable file size for uploading onto this forum!
     

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    #469 Micanopy Mike, Apr 18, 2018 at 9:45 AM
    Last edited by a moderator: Apr 18, 2018 at 9:31 PM
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  10. N6BY

    N6BY Geek
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    Welcome to the discussion.

    The GRB signal looks good as displayed in your photo. But unfortunately NOAA decided to include both polarities (LHCP and RHCP) at the same frequency. So with your linear polarity feed you're getting a mixture of both signals, and it would be impossible to process. A RHCP or LHCP circular polarity feed with good cross-polarity isolation is required for receiving GRB

    The information content is different on the two polarities. A list of the contents of each polarity is below. It's from the GOES GRB Product Users Guide.

    allocation.png
     
  11. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    Hi Micanopy Mike,
    Welcome.
    I don't need that hardware as I have a GVAR station here now. I am currently using GOES West.
    That hardware should be fine for GOES West but that satellite will be replaced by the end of the year with the "S" satellite or know known as GOES 17.
    GVAR is on the way out so that's why were here discussing this. GRB unlike GVAR uses DVB-S2 format instead of the BPSK stream.
    The nice thing about the new format is that the hardware is much more available to the user then when it was GVAR. However.. due the the bandwidth constraints NOAA packed all they could into 12 Mhz using both polarization's. This has caused a real headache for us as it requires some skill to get both streams.
    Along with what N6BY posted above it also takes an 8' dish on the east coast Min 10' if you want both streams for GRB, a waveguide feed of the septum type or the cantenna type.
    Again the feed must be circular polarized.
    A patch antenna may not work for this as it don't have the best match for a dish. You can try it, let us know.
    In my case I am only after the one stream so the setup is not as complex as the latter.
    Anyway, I will be here more over the weekend and hopefully have another dump ready. Have had little time and the weather has been relentless here.

    Also another little update, so far Novra seems to be very interested and is looking good. It got even better as CSPP Geo wanted to get in touch with them and coordinate their software with Novra's receiver.

    Also I will send you the Code for that display program I talked about Brett, see if you want to even look at it.
     
  12. Micanopy Mike

    Micanopy Mike New Member

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    Hello, N6BY--

    It is Brett, isn't it? I think that is what I saw on the FCC license listing. I have been
    WA4HFR since around 1963. Some background on me; I built a GOES-East GVAR
    station for the U of Fl Climatology Research Department in 1981. The Climatology
    Department had a NASA contract to improve the freeze forecasting algorithms
    for the cold-sensitive agricultural interests of the state of Florida. Back then
    GOES products and imagery were not available on the Internet and the only way
    to acquire them in real time required a direct down-link.

    There was a huge clamor by local hams to receive the animated CONUS and
    Florida image sector. I (illegally) installed a 70-ft tower on top of my 4-floor office
    building and put an 18-ft tall stacked co-linear 13 dB gain omni-directional
    Super Stationmaster antenna on the tower. My office was on the 4th floor
    directly under the tower and I ran a 100-ft length of 1-inch Andrews Heliax
    hard-line coax down from the antenna and connected it to an amp from a
    defunct low-power TV station. The amp used a single Eimac 8877 (3CX1500)
    tube running full-legal power NTSC video on the ham 426.25 70cm band.
    With NTSC video, maximum average power applied to the antenna system
    is 57% of the peak sync tip power, even in a black scene. In normal program
    content this ratio may be around 25% or less. The nature of the GOES GVAR
    imagery was such that with such an effective antenna system the TX met
    all power restrictions.

    Clear video was easily received out to around a 25-28 mile radius from my
    office. This system ran 24/7/365 as a "beacon" for almost 10 years. Eventually,
    the GOES imagery became available on the Internet and the transmitter
    system was shut down.

    The RX consisted of an 16-ft dish feeding a de-mod box and a bit-stream
    synchronizer followed by some TTL hardware to decode the incoming data
    and then into an Amiga 2000 desktop computer to turn the data into
    image pixels and scan lines and then convert this into NTSC video.

    I had some experience with video as I had been chief-engineer for the
    U of F TV station WUFT-TV5 for several years. Interestingly, here in Florida
    hams use the 70 cm band on a secondary basis with the military as there
    is a bombing range not far from us near the Ocala National Forest and
    hams are limited to 50 watts TX power. A friend of mine was in charge
    of communications for the military in this region and I appealed to him
    for a power waiver. After about a month I received a document permitting
    me to run full legal power if I changed my originally selected frequency to
    426.25 MHz as the military was not using anything close to that exact
    frequency. I framed that letter and hung it on the rack holding the TX.
    The Eimac 8877 tube was capable of loafing along running 1500 watts
    peak video sync-tip power. The 8877 tubes were expensive and started to
    get soft after around 8K or 9K hours. Every year or so the 40 or 50 area hams
    watching the GOES GVAR video took up a collection for a new tube.

    Eventually, the GOES GVAR downlink was shut down when the NASA
    development contract ended and the GVAR system was declared
    surplus, dismantled and declared available for salvage. Unfortunately,
    the dish was acquired by another U of F department. I saved the
    GVAR modem and bit-sync and took my tower and antenna home.
    It was a fun side-line project while it lasted!
    **************
    My current interests are: A) Downlinking the new GOES-East EMWIN
    signal and eventually; B) Downlinking the GOES East GRB signal. I am
    primarily interested in the animated Geo-Color imagery. However,
    it is not clear to me if this product is contained in just one circular
    polarity signal or if it requires processing both circular polarity
    signals to produce. Any info on this will be much appreciated!!
    *************

    One last item: You said--
    > A patch antenna may not work for this as it don't have the best match
    for a dish. You can try it, let us know.
    *******

    Hmmmm.... CP Patch feeds are commonly used on commercial
    V-sat off-set (and some prime-focus) dishes. I do get more GRB
    signal with the CP patch than with the linear polarity feed but I will
    have to take another look at it and let you know what I see.
    *********

    Yikes-- I see that I have gotten carried away with far too long of a
    text post. I tend to do that... My apologies!

    Mike Baker
    *********
     

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