Posts by DB2OS

    An intro video from Kurt DJ0ABR is now available on YouTube with german audio, but hopefully english subtitles will be available when YouTube created them automatically:


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    As previous year, local club F4KLK-Electrolab hosts the "AMSAT-F days" this week-end (2022, May 7-8)


    Presentations from both days will be transmitted via QO-100 with the following parameters :


    Transmission mode :

    • DVB S2,
    • FEC : 1/2
    • Format 720 p


    This is a two days live transmission on the WB-Transponder in agreement with the WB bandplan and guidelines, approved by AMSAT-DL.


    Hi,

    I have a proposal for a "new" operational mode for NB.

    The traditional QSO using USB in all frequencies is half duplex. This is due to the fact that is impossible to Rx during Tx. Using USB is possible two stations or more to talk at the same time without interfering each other.

    The proposal is that two or more stations talk together like a telephone conversation. Of course callsigns must told every few minutes according to ham radio laws.

    This will provide a more "natural" mode of communication that is impossible to implement with out QO100.


    Hi George,


    Sorry - I don't get it.. I'm confused..


    Isn't this what is already mandatory according our NB Transponder Bandplan and Guidelines which state:


    --> Full-Duplex operation is mandatory


    Thus, your equipment shall be designed for Full-Duplex, i.e. RX and TX capable at the same time,.


    Some operators do already practice that, even in larger rounds. When two people start to talk together at the same time, the other will stop or the 3rd. person will listen to both of them at the same time..


    For that reason since the launch of QO-100 we have always advocating to build or buy full-duplex equipment. Unfortunately some vendors constantly ignore this request,


    However - sometimes you also hear people talking many minutes over each other. They may not have that capability our just turned their audio down while talking, not to get confused because of the delay..


    But anyway, good that you bring up this discussion again.


    73s Peter

    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