Posts by DB2OS

  • UoSAT-2 (OSCAR-11) still transmitting data

    Here are all the UoSAT-1 bulletins starting with issue #10 until #109 when I stopped printing them.

    I did not had a printer before #10 :)


    Thanks to Matthias DD1US for hosting my scans:


    UoSAT-1 bulletins #010 - #040 received by DB2OS

    UoSAT-1 bulletins #041 - #064 received by DB2OS

    UoSAT-1 bulletins #065 - #079 received by DB2OS

    UoSAT-1 bulletins #080 - #100 received by DB2OS

    UoSAT-1 bulletins #100 - #109 received by DB2OS


    I agree with Lucio, it was a great time when we had to send receiving reports by postal mail to Martin Sweeting and his team to the University of Surrey in Guildford.


    There was a big community eagerly waiting for a new UoSAT bulletin to be downloaded every weekend.


    Internet was not existing at that time, so it was a fantastic resource of latest information from the AMSAT and hamradio community world wide -, see yourself above.


    It's a pity that 39 years later many LEO's even don't give a glimpse of that..

    UoSAT-1 OSCAR-9 was launched in 1981.


    UoSAT-2 OSCAR-11 launched in 1984 was carrying the first Digital Communications Experiment (DCE) which allowed Store&Forward communication based on simple asynchronous communication protocols.

    I was very happy at that time to participate as one of very few UO-11 groundstations.


    The DCE was the forerunner of the PACSAT satellites using AX.25 based PACSAT Broadcast Protocol (PBP).


    I believe FalconSAT-3 launched in 2007 is the last OSCAR with a PACSAT BBS onboard.

     

  • 40cm dish

    Achim DH2VA has graphically illustrated the relationship between the various dependencies and how the SNR behaves with the size of the dish or which factors dominate. The graphics are also part of our official QO-100 presentation.



    The blue curve shows that a small dish leads to considerable disadvantages, but the advantages above 1-1.5 meters are at some point only in the range below 1dB.

  • LNB-Umbau

    Achim DH2VA hat den Zusammenhang der verschiedenen Abhängigkeiten einmal grafisch dargestellt und wie sich das SNR mit der Größe des Spiegels verhält bzw. welche Faktoren dominieren. Die Grafiken sind auch Bestandteil unser offiziellen QO-100 Präsentation...







    Die blaue Kurve zeigt, dass ein kleiner Spegel zu erheblichen Nachteilen führt, aber die Vorteile oberhalb 1-1.5 Meter irgendwann nur noch im Bereich von unter 1dB liegen....

  • 40cm dish

    A dish size of 60cm-75cm is strongly recommended if you want to receive hassle free.

    A smaller dish would exceptionally for portable operation.

    But it is definetly not optimal and you may not hear weaker stations on the satellite with a smaller dish.


    Keep in mind: To be as loud as the beacon is not the goal, it is the maximum limit!


    There should always be a good balance between receive capability and transmit power.. the "alligator" phenomena..

  • AMSAT-DL QO-100 DownConverter V3d: how to connect OLED

    Hi Gustav,


    this is from another thread

    AMSAT-DL Sende- und Empfangsmischer für QO-100 (P4-A)

    maybe it helps.. see below...


    73s Peter


  • AMSAT P3-A

    I8LYL former I0LYL

    Hi Lucio, that's so true.. time is running...

    I started with OSCAR-7 and OSCAR-8 and remember when my brother and me were listening on Shortwave for the launch live broadcast from the FY7KRU clubstation. https://amsat-dl.org/en/amsat-phase-3-a/ It was indeed a very sad day, but P3-B (OSCAR-10) was launched only 3 years later and still is in orbit.. it's battery is open, but I don't know if someone was still listening during the last couple of years ;)


    73s Peter

  • AMSAT P3-A

    40 years ago: 23 May 1980, (unsuccessful) launch of German Firewheel and AMSAT Phase 3-A (OSCAR-9) satellites on Ariane1 L02 rocket. P3-A was an open source and open hardware project developed in the 70ies by AMSAT-DL and AMSAT-NA. It carried a communication payload consisting of 50 Watt Mode-B (435 MHz → 146 MHz) linear-transponders and a freely programmable on-board computer running the open source operating system IPS developed by Karl Meinzer DJ4ZC. This historical video thankfully made available by CNES shows details from the launch campaign and the P3-A satellite which was probably never seen before in public..


    see this Video (without Audio!) https://videotheque.cnes.fr/in…rlaction=doc&id_doc=25811


     

  • Welche Rundstrahlantenne für VHF-Empfang von Satelliten

    Zum Thema preiswerte Lösung für AZ/EL-Rotor mittels billiger DiSEqC-Motoren hier noch ein Hinweis:


    -------- Weitergeleitete Nachricht --------

    Betreff: Re: [amsat-bb] DiSEqC Antenna Tracker System, HB9SCT

    Datum: Fri, 15 May 2020 09:42:38 +0100

    Von: Daniel Cussen via AMSAT-BB <amsat-bb@amsat.org>

    Antwort an: dan@post.com

    An: Gregory Beat <w9gb@icloud.com>

    Kopie (CC): amsat-bb <amsat-bb@amsat.org>



    I am based in Ireland. I have investigated diseqc as a means of rotator

    control and I have generated custom messages using a windows PC


    See here for video


    External Content www.youtube.com
    Content embedded from external sources will not be displayed without your consent.
    Through the activation of external content, you agree that personal data may be transferred to third party platforms. We have provided more information on this in our privacy policy.



    I used some basic electronics to 'wiggle' the voltage to the rotator to

    generate the diseqc signal.


    I know others have done this too.


    I was most interested in building an XY rotator using two off the shelf

    diseqc domestic rotators. I chose xy over azimuth elevation for 2 reasons,

    one the standard diseqc dish rotators typically only rotate 1/2 or 3/4

    turn, and XY is better for fast overhead passes at microwave frequency


    Using the software in that video, and a couple of components you can send

    messages to that rotator.


    I also used a similar set up to reverse engineer and send custom diseqc

    commands to other domestic satellite equipment equipment such as a DirecTV

    downconveter.


    I never really completed or documented my work properly, but I have some

    records and the hardware.


    It might be possible to modify specific diseqc rotators to travel beyond

    1/2 a turn, however an XY design needs little modification. I have a non

    diseqc XY rotator which I have used in the past and it is superior on high

    passes at microwave frequencies.


    I have also build other arduino rotator controllers.


    Any questions please ask on or off list


    Dan EI9FHB

  • Welche Rundstrahlantenne für VHF-Empfang von Satelliten

    Quote from DB2OS

    mit WiMo TA-1:


    und hier nach rund 6 Monaten die gleiche Auswertung mit der ANjo-Eggbeater:

    Ich denke das Ergebnis kann sich durchaus sehen lassen, Wunder darf man natürlich auch nicht erwarten.

    Die Signalstärken sind aber spürbar stärker geworden´und es gibt auch weniger tiefe Nullstellen wie bei der TA-1.

    Auch in der Statistik bei https://www.amsat.org/tlm/leaderboard.php?id=0&db=FOXDB habe ich mich im Vergleich zu den "big guns" mit größeren Richtantennen ziemlich hocharbeiten können :)


    Zum Empfang habe ich einen Raspberry PI4 mit der Fox-TLM Software verwendet, einem FunCube V2.0 Pro Plus Dongle und direkt an der ANjo-Eggbeater ein SSB SP-200 2m-Mastvorverstärker.

    Das Experiment mit den Fox-Satelliten und dem Telemetry Analysis Tool ist nun beendet.

    Jetzt probiere ich mal nebenbei wieder etwas anderes aus... SatNOGS...


    73s Peter

  • Welche Rundstrahlantenne für VHF-Empfang von Satelliten

    Quote from HB9SKA

    Die meisten, wenn nicht alle, CubeSats sind elektromagnetisch Spin-stabilisiert und sollten daher nicht taumeln. Jedenfalls empfange ich sie alle mit einer vertikal polarisierten 11-Element-Yagi.

    Hallo Thomas,


    das ist so leider nicht ganz zutreffend.. und auch wenn sie Spin-stabilisiert sind, so wären auch dann die Antennen nicht immer zur Erde ausgerichtet und auch nicht zu Dir als Beobachter... die Blickrichtung und Polarisation ändert sich ständig.

    Man sieht das auch schön auf den Bildern von FOX-1D.. Der Auslöser hat einen Algorithmus der prüft ob die Erde in der Optik ist. Manchmal löst er trotzdem aus und dann sieht man nur den dunklen Weltraum mit den Antennen im Vordergrund..


    73s Peter

  • "SEARCH" in this Forum

    Yes, we have a Search function..



    if you click on it, another box will show up:



    You should see this in english translation too.


    If you are inside a thread or sub-forum, please make sure to select "All" otherwise it will only search in the thread which you are currently in.


    Under extended search you will find more option..


    Please use the SEARCH function before openening another thread for the same topic!

    This makes it much easier for other readers and also for the admins..


    Thank you!

  • Welche Rundstrahlantenne für VHF-Empfang von Satelliten

    Quote from oe9dgv

    Apropos 2m / 70cm Satelliten Antennen: Gibt es einen Az/El Rotor für kleine Antennen mit Steuerungsmöglichkeit zu vernünftigem Preis?


    For 2m / 70cm satellite antennas: Is there an Az / El rotor for small antennas with control options at a resonable price?


    73 Guntram oe9dgv

    Hi Guntram,


    ich bin gerade über diese Meldung im AMSAT-BB gestollpert.


    Ich hatte auch schon mal in diese Richtung dedacht und mich gefragt warum das DiSEqC-Protokoll/Hardware im Amateurfunk eher unbekannt ist. Zumidest im QO-100 Downkonverter ist ein entsprechendes Interface eingebaut, auch wenn es momentan nur zur Spannungsversorgung eingesetzt wird.


    Hier die Meldung mit interessanten Links:

    -------- Weitergeleitete Nachricht --------

    Betreff: [amsat-bb] DiSEqC Antenna Tracker System, HB9SCT

    Antwort an: Gregory Beat <w9gb@icloud.com>


    Anyone in North America experimenting with DiSEqC Control for Tracking ??

    https://en.wikipedia.org/wiki/DiSEqC


    DiSEqC (Digital Satellite Equipment Control), pronounced "Die-Sec", is a special communication protocol for use between a satellite receiver and a device such as a multi-dish switch or a small dish antenna rotor. DiSEqC was developed by European satellite provider Eutelsat, which now acts as the standards agency for the protocol.


    DiSEqC Protocol and Low-Noise Block Voltage Regulator TPS65235 for Satellite

    by Na Xu, Texas Instruments (December 2016)

    http://www.ti.com/lit/an/slva8…863.pdf?&ts=1589027212595

    ===

    DiSEqC : Low Cost Antenna Tracker

    Christian Monstein, HB9SCT (Switzerland)

    http://www.e-callisto.org/Hard…seqc/SARA%20Diseq_V01.pdf


    Callisto DISEqC Controller (June 2018)

    http://www.e-callisto.org/hardware/Diseqc/Doku%20Diseq.pdf

    The key components (and most expensive ones) are two DiSEqC motors (Az-El) and the Arduino micro-controller. Callisto Hardware - Knowledge Library.

    http://www.e-callisto.org/Hardware/Callisto-Hardware.html


    STAB (Italy), HH100, HH120 rotors (~ € 85.00)

    http://www.stab-italia.com/prodotto.php?cod=F208010

    HH100, HH120 Manual

    http://www.stab-italia.com/dow…0%5BEN-DE-IT-FR-ES%5D.pdf

    ==

    greg, w9gb



  • Welche Rundstrahlantenne für VHF-Empfang von Satelliten

    Es gibt (gab) auch tieffliegende OSCAR's mit zirkularer Polarisation, z.B. AO-16 oder AO-51.. teilweise RHCP, teilweise auch LHCP !

    Beispiel: https://www.pe0sat.vgnet.nl/antenna/polarization/

    Auch die Abstrahlung am Satelliten ist nicht immer ideal, abhängig vom Blickwinkel kann es von RHCP über linear auch mal zu LHCP drehen...


    Bei den CubeSats aufgrund der Größe meist nur LINEAR...

    Wie von Robert und Matthias schon beschrieben, sollte man auch hier definitiv zirkular polarisierte Antennen verwenden...





    Gruß Peter