20.6°E SBIRS-Geo 2 (incl.) (OLD POSITION Data>Ka C)

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    This is a satellite in inclined orbit (low level under the Clark belt)


    Scan in Range C (nothing in A B D)

    Bilder

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    Thanks

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    Gilat feed on Gilat band B LNB linear polarised, 1.2m offset


    It's still there and looks like BPSK but I think that CS flips between 2 phases making it look like QPSK.

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    From McCants' TLE this appears to be moving east and is around 27.8E at the moment.
    http://www.n2yo.com/?s=39120

    1.2m Prodelin 3122 az-el with one of:
    S: Helical feed, 0.8dB NF LNA, X: 1.2dB NF LNA, conical feed,
    Ku 12-18GHz: corrugated conical feed, 1.5dB NF LNA, Ku (Standard): SMW Q-PLL type C, Prodelin feed. Ku (Extended): 11.3GHz LO SMW & Prodelin Feed Ka: Gilat ex-ODU PLLs Gilat feeds, Ka 18-26.5GHz: Patriot feed, home made 4dB NF LNA, Ka DSN: Corrugated conical feed, home made 3dB NF Down-Converter

    1.5m IRTE, Polar mount with Octagon OSLO mod. C120, IRTE feed
    40km East of London, UK

    Einmal editiert, zuletzt von s-band ()

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    Hello s-band,


    This is no so, I need to explain a little! The problem with McCants' TLE's is, they are refreshed seldomly. For many of these satellites, there are several months between observations.


    In this example with SBIRS-Geo 2, the observation date (epoch) is 29 October 2017. Whatever little drift the satellite had at that moment, will propagate further for every day since 29 October. In reality, the satellite will be manoevered every few weeks to keep it in correct position.


    So in fact, a TLE is only reliable near epoch date. In the software that I use to read TLE's, I check the longitude of a satellite for 2 Clarke-belt passes near epoch date (about 12 hours apart), and take the average of these longitudes for my Sats list. There also the epoch date is listed in the comments column (ep. '17-10-29 in this case).

    • Offizieller Beitrag

    Ah, thanks, I thought something was strange as the positions I got from WXTrack with McCants' latest were different from N2YO, but still apparently wrong. I will treat the data with more caution from now!

    1.2m Prodelin 3122 az-el with one of:
    S: Helical feed, 0.8dB NF LNA, X: 1.2dB NF LNA, conical feed,
    Ku 12-18GHz: corrugated conical feed, 1.5dB NF LNA, Ku (Standard): SMW Q-PLL type C, Prodelin feed. Ku (Extended): 11.3GHz LO SMW & Prodelin Feed Ka: Gilat ex-ODU PLLs Gilat feeds, Ka 18-26.5GHz: Patriot feed, home made 4dB NF LNA, Ka DSN: Corrugated conical feed, home made 3dB NF Down-Converter

    1.5m IRTE, Polar mount with Octagon OSLO mod. C120, IRTE feed
    40km East of London, UK

    • Offizieller Beitrag

    Indeed s-band, you noticed well, WXtrack and other softwares that use David Taylor's dll have a longitude error on several inclined satellites, including SBIRS-Geo 2.
    He acknowledged the problem when I showed him a few years ago, but was unable to fix it, unfortunately.
    GorbTrack that is so convenient for checking GEO satellites is also affected.
    Satellites that have a "!" in the remarks of my list have a longitude error in GorbTrack, then for a correct calculation I revert to the Gpredict software.

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    Tonight scan 20252 & 20460 on


    (nothing in X)

    • Offizieller Beitrag
    Zitat

    Original von Feedsat
    Tonight scan 20252 & 20460 on


    (nothing in X)


    Are you sure it is not SBIRS Geo 2?


    /edit by qwer: LINKs disappeared (01.08.2020).


    If it is, it should be getting weaker by now unless you are using inclined tracking.

    1.2m Prodelin 3122 az-el with one of:
    S: Helical feed, 0.8dB NF LNA, X: 1.2dB NF LNA, conical feed,
    Ku 12-18GHz: corrugated conical feed, 1.5dB NF LNA, Ku (Standard): SMW Q-PLL type C, Prodelin feed. Ku (Extended): 11.3GHz LO SMW & Prodelin Feed Ka: Gilat ex-ODU PLLs Gilat feeds, Ka 18-26.5GHz: Patriot feed, home made 4dB NF LNA, Ka DSN: Corrugated conical feed, home made 3dB NF Down-Converter

    1.5m IRTE, Polar mount with Octagon OSLO mod. C120, IRTE feed
    40km East of London, UK

    Einmal editiert, zuletzt von s-band ()

    • Offizieller Beitrag

    You re right. Thanks for the correction. :73:


    hvdh: moved today's messages from 21.5° SES-16 to here.

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    Just my (circular left) scan here on 1.2m.


    20462 is much weaker.

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    A bit stronger in circular right scan (20462).


    Had to test linear scan next time here.

    • Offizieller Beitrag
    Zitat

    Original von qwer


    Had to test linear scan next time here.


    Okay, just doing my lessons... :96: much weaker signal in linear vertical here - 20462 not "visible" in spectrum.

    Bilder


    • Offizieller Beitrag
    Zitat

    Original von qwer


    Okay, just doing my lessons... :96: much weaker signal in linear vertical here - 20462 not "visible" in spectrum.


    Hmm, I think that they are both circular. I am using a linear feed and they do not change when it is rotated. I suppose they may be opposite circular but I can not check. Here are today's plots. 20.4625 may be stronger than shown as I am using a band B LNB.

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    Yes, best signal in circular - than you s-band!.


    • Offizieller Beitrag
    Zitat

    Original von qwer
    Yes, best signal in circular - than you s-band!.


    I checked and they are RHCP

    1.2m Prodelin 3122 az-el with one of:
    S: Helical feed, 0.8dB NF LNA, X: 1.2dB NF LNA, conical feed,
    Ku 12-18GHz: corrugated conical feed, 1.5dB NF LNA, Ku (Standard): SMW Q-PLL type C, Prodelin feed. Ku (Extended): 11.3GHz LO SMW & Prodelin Feed Ka: Gilat ex-ODU PLLs Gilat feeds, Ka 18-26.5GHz: Patriot feed, home made 4dB NF LNA, Ka DSN: Corrugated conical feed, home made 3dB NF Down-Converter

    1.5m IRTE, Polar mount with Octagon OSLO mod. C120, IRTE feed
    40km East of London, UK

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    Just another spectrum.


    /edit: linear scan.

    Bilder


    • Offizieller Beitrag

    Just another look on 20251 in circular now. (Inclination 1,41° at scan time)

    Bilder


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    Today I´m sure about this satellite (it was 2,21°inclined at scan time) and nothing in band B.

    Bilder


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