Posts by DB2OS

    There are several satellites transmitting in the 435-438 MHz amateur satellite band. Unfortunately some of them are purely commercial, which is alarming indeed.

    … good to see that at least some commercial satellite operators finally decided to be “good” and move out of the 435-438 MHz amateur satellite band ...


    This page is currently a very good resource for current status of the launched satellites:

    https://community.libre.space/…er-3-2022-01-13-15-25utc/

    The State Secretariat of Spain for Telecommunications and Digital Infrastructures has granted authorisation until 26 December 2022 to holders of amateur radio authorisations to carry out amateur service broadcasts in the 2410 MHz frequency band from 2.400,050 to 2.410 MHz, with a maximum e.i.r.p. of 1500 watts and using directional antennas with a gain of not less than 21.5 dBi, from authorised amateur radio stations located anywhere in the national territory to the QO-100 satellite located at orbital position 25.9°E of the geostationary orbit.



    https://www.ure.es/2-400-mhz-autorizacion-general-2022/

    https://www.ure.es/images/noti…/RESOLUCION-CONCESION.pdf

    The State Secretariat of Spain for Telecommunications and Digital Infrastructures has granted authorisation until 26 December 2022 to holders of amateur radio authorisations to carry out amateur service broadcasts in the 2410 MHz frequency band from 2.400,050 to 2.410 MHz, with a maximum e.i.r.p. of 1500 watts and using directional antennas with a gain of not less than 21.5 dBi, from authorised amateur radio stations located anywhere in the national territory to the QO-100 satellite located at orbital position 25.9°E of the geostationary orbit.



    https://www.ure.es/2-400-mhz-autorizacion-general-2022/

    https://www.ure.es/images/noti…/RESOLUCION-CONCESION.pdf

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    Hello OM,


    The CAMSAT XW-3 (CAS-9) amateur radio satellite will be launched at UTC 03:11:31 on 2021-12-26 , and will be deployed at 98.858° east longitude and 28.413° north latitude at UTC 03:35:58, location close to Western Australia.


    Radio amateurs will receive CW beacon and GMSK telemetry signals approximately 38 seconds after the satellite is separated from the launch vehicle, and then the linear transponder will be put into use after approximately 49 seconds.


    Preliminary TLE:


    XW-3(CAS-9)

    1 99999U 21360.14997609 .00000032 00000-0 10363-4 0 00007

    2 99999 098.5836 072.3686 0004232 307.2415 261.3002 14.38559758000156


    IARU coordination: http://www.amsatuk.me.uk/iaru/…_detail.php?serialnum=804



    Attached is the launch schedule.


    73!

    Alan Kung, BA1DU

    Hello OM,


    CAMSAT XW-3(CAS-9) satellite has been installed on the CZ-4C Y39 launch vehicle at the Taiyuan Satellite Launch Center in China, and related work is in progress as planned.


    If all goes well, the satellite will be launched on December 25, 2021,it is piggybacked on the rocket with governmental primary payload ZY-1(02E) earth resources satellite. The orbit will be a circular sun-synchronous orbit with an altitude of 770.1 kilometers and an inclination of 98.58 degrees, the running cycle is 100.14 minutes.


    Attached is the user's manual of XW-3 (CAS-9) satellite for radio amateur, precise TLE will be available later.


    73!
    Alan Kung, BA1DU

    CAMSAT

    The Beacons are actually the Satellite-to-User Downlink traffic in 250 MHz channels (see chart in my first post) at 11.075, 11.325 and 11.575 GHz. Other channels might not be in use yet.


    Christian Hahn in California made some cool observations and analysis:



    The central 1 MHz of each 250 MHz channel is occupied by ~9 tones spaced at 43.9495 kHz. 1 tone on the channel center, 4 tones on each sideband.



    Christian found out that the central 9 tones sometimes are missing.

    There is still some guess that the tones in the middle are low speed data carrying the satellite id number and orbital elements of nearby or all active satellites for tracking...


    73s Peter

    Actually it's a surprise that we even do see something from Starlink with the QO-100 dish pointing to 25.5°E.

    To avoid interference between geostationary (GSO) and non-geostationary (NGSO) satellite systems, FCC and national regulations require that the user beams are switched away to an alternative satellite when the user terminal is pointing to the geostationary belt and GSO downlinks...

    Maybe we are seeing are actually the side lobes or something else. On the other hand, these signals are probably some telemetry beacon downlinks used for initial tracking when searching and aligning the Dishy terminal for the first. They might carry some sort of satellite elements. Remember that Dishy does not have any internet connection and does not know where it is located and where to point in the sky to establish first contact and align itself..



    Anyway.. fascinating technology behind this and fun to play with..

    Next thing would be to use a bare LNB pointing straight up..


    73s Peter

    You only need to wait a few minutes and you will see something like this, as seen on my QO-100 dish (SDR console tuned to 11.325 GHz):



    Also keep in mind that we are only seeing a side lobe as usually the main lobe is more or less directed perpendicular to the user station on the ground. So if you just mount your LNB without reflector looking vertically up, you might even see more...


    73s Peter

    Hi,


    the famous SpaceX/Starlink satellites have downlinks in the Ku-Band as shown in this band allocation below.




    This is indeed the same band used for Direct-TV geostationary satellites and also QO-100 (there are also downlinks in the Ka-Band for the Gateway-Links, but this is not the scope here).


    OH MY GOD - ITS FULL OF STARS


    here you can find some Starlink Coverage Tracker:

    https://satellitemap.space/

    https://starlink.sx/


    Same minds, same thoughts...

    So, why not using a simple LNB as we use for QO-100 and try to receive Starlink satellites instead. Just point the LNB in the Sky and use an SDR to check if you can see something in the waterfall spectrum with your favorite SDR software. Indeed you may see only part of the signal as it is high bandwidth, but there are also some telemetry beacons like on 11.325 GHz.


    Starlink Downlinks are usually circular polarized (RHCP/LHCP), so your LNB's linear polarization (H/V) does not matter!


    Some people (including I0LYL) have just used their QO-100 installation and waited until a Starlink satellite just (quickly) passed through the antenna beam...


    Here is a pretty nice article from Derek OK9SGC with full explanation and further links:

    https://sgcderek.github.io/posts/starlink-beacons/






    Have fun!

    73s Peter DB2OS

    The old QO-100 bandplan is still floating around on the internet (narrowband uplink: 2400.050 - 2400.300 MHz). I think the club chaps weren't aware of the transponder band expansion or the unusual nature of the transponder in general.


    Easy mistake to make I think ;-)


    Hi Michael,


    actually IARU has been informed about this when the proposal came to move terrestrial into the satellite bandplan.

    Unfortunately someone ignored it or underestimated the impact. :/


    73s Peter

    Yes, and look who's report was re-printed in the article... "received by DB2OS".

    Recently I found UoSAT-1 OSCAR-9 Bulletin #10, received in 1200 Baud FSK, ASCII format.

    We sent our reports and telemetry by postal mail, as the Internet was not exisiting yet.



    Hi Alex,


    according to the system you are registered as "guest", i.e. without active account. An registered account is not required for the order, so maybe something was missing.


    You should have received an personal eMail by now. If not, let me know..


    73s Peter