Transmit digital television signals over Qatar Oscar 100 satellite

Intro

Following my previous article on the transmission to the Qatar Oscar 100 satellite with SDR technology (LimeSDR, Adalm pluto) which was dedicated to the narrow-band transponder transmission (SSB and modes with spectral width less than 2.7 kHz), here is an article that should this time interest those who are willing to embark on the digital amateur television program, commonly called DATV (Digital Amateur Television).

As you may have read so far, I have a LimeSDR-mini but now also an Adalm Pluto. During one of my conferences (in french – see Amsat Francophone Conference), I had the occasion to compare the two equipments, their advantages and disadvantages. I had the experience to transmit in DATV to QO100 with both the LimeSDR-mini and the Adalm Pluto. Both models work very well, but I will focus in this article on the use of the Adalm Pluto, because finally it is today the solution that is the easiest to implement. Indeed, to transmit with LimeSDR, a Raspberry Pi is necessary. In the case of the Adalm Pluto and especially thanks to the developments of a specific firmware of Evariste F5OEO, we do without this nanocomputer, the Adalm rather embedding the software directly.

In this article, as usual, we will go step by step through all the operations described as precisely as possible.

I use the Windows operating system. I won’t go into the details of the operation of the transmission modes themselves, not being a specialist in the fundamentals.  My goal is to bring to your knowledge all the steps that will allow you to build your own transmitting station, and transmit images. It is possible that the software evolving, certain functions, or operations themselves are to be made evolve. Do not hesitate to submit your questions, problems of implementation directly in comment of the article.

Here is the diagram of principle which we will implement, to transmit our DATV videos to the QO-100 satellite.

Schematic diagram of a DATV broadcast with OBS Studio and Adalm Pluto or LimeSDR

I don’t come back in this article to the basis of adjustment of dishes, antennas, transmitter that you find in my previous articles ( Receiving Qatar Oscar 100 satellite with SDR Console , The transmission over Qatar Oscar 100 satellite with SDR Console).

Let us remind in the preamble that radio broadcasting is regulated at the international level, at the national level and that only holders of class 1 and class 2 amateur radio licences are authorized to transmit on the allocated frequency bands.

This article is “multi-page”, to browse from one page to another or directly from the table of contents to the desired page.

11 thoughts on “Transmit digital television signals over Qatar Oscar 100 satellite

  1. Christian,

    Congratulations, this is one of the Blog articles I’ve read about how to setup a DATV station for QO-100.

    Thanks for sharing with the community.

    73’s
    Alex EA4BFK

    (Traduction)
    Christian,

    Félicitations, c’est l’un des articles de blog que j’ai lu sur la façon d’installer une station DATV pour le QO-100.
    Merci pour avoir partagé avec la communauté.

    73’s
    Alex EA4BFK

    1. Merci Christian Superbe tuto !! A bientôt sur QO-100
      73 de ON1RC
      Chris

      (Translation)
      Thank you Christian Superb tuto ! See you soon on QO-100
      73 from ON1RC
      Chris

      1. Bonjour Christian
        Mais quel superbe outil de travail, moi qui suis totalement néophyte dans le mode DATVet dans l’utilisation du logiciel OBS.
        Me voici équipé pour comprendre le fonctionnement et pouvoir parfaire mon installation.
        Félicitations pour la qualité de tes tutos qui sans nul doute vont être un fabuleux tremplin à beaucoup pour créer sa station.

        73 cordialement salutations et au plaisir de te retrouver sur le satellite Q0-100. F3CJ

        (Translation)
        Hello Christian
        But what a great tool, I’m a total neophyte in the DATVet mode in the use of OBS software.
        Here I am equipped to understand how it works and to be able to perfect my installation.
        Congratulations for the quality of your tutorials which will undoubtedly be a fabulous springboard for many to create their station.

        73 cordially greetings and I look forward to seeing you on the Q0-100 satellite. F3CJ

  2. Merci beaucoup Christian.
    Des informations très précises et détaillées.
    Superbe.
    73 de Aitor F4VTB EB2AT

    (Translation)
    Thank you very much, Christian.
    Very precise and detailed information.
    Superb.
    73 of Aitor F4VTB EB2AT

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  4. Thanks for the wonderful guide. Very comprehensive. Thanks again for sharing your experiences. With gratitude 73 de Ros i4wrm

    (Traduction)
    Merci pour le merveilleux guide. Très complet. Merci encore de partager vos expériences. Avec reconnaissance 73 de Ros i4wrm

  5. Bonsoir Christian F5UII,

    Merci pour votre tuto, très instructif. J’ai échangé avec Pascal F4BRF et Nicolas FR4LI au sujet de la modification à base de 2 x 4N35 (montage vu sur le net pour l’ADALM PLUTO).L’idée, une commutation TX/RX pour la partie amplificateur SG-LAB depuis le PLUTO.
    J’aimerai avoir votre avis avisé sur le sujet svp. En vous remerciant par avance.
    Au plaisir de vous lire Christian F5UII.
    73 de Axel FR5GS

    (Translation)
    Good evening Christian F5UII,

    Thank you for your tutorial, very informative. I discussed with Pascal F4BRF and Nicolas FR4LI about the modification based on 2 x 4N35 (assembly seen on the net for the ADALM PLUTO) The idea, a TX/RX switching for the SG-LAB amplifier part from the PLUTO.
    I would like to have your opinion on the subject please. Thank you in advance.
    Looking forward to reading you Christian F5UII.
    73 from Axel FR5GS

    1. Oui, le logiciel SDR Console et également le firmware PlutoDVB d’Evariste F5OEO pilotent les sorties GPO0 et GPO1 lorsque l’on passe en émission. On utilise les 2 sorties car toutes les deux passent en émission à la mise sous tension du Pluto pendant environ 5 secondes.
      Commutation émission PTT sur Adalm Pluto SDR
      On trouve deux schémas permettant la commutation PTT, l’un à base d’optocoupleurs, l’autre à base de transistor et relais reed. J’ai choisi de mettre en œuvre la seconde technique, avec double circuit de commutation, permettant d’alimenter distinctement 2 sorties indépendantes. Une commande groupée sera certainement prochainement proposée. Tous les détails sur cette page.
      Il existe une autre solution, mais que je ne conseille pas au vu du risque engagé sur le Pluto. Il s’agit de celle qui consiste à détecter l’activité du bit0 du bus 12 bits du convertisseur numérique /analogique. Pour la curiosité, je vous laisse découvrir cette mise en œuvre de DH1NFJ sur ce site internet (langue allemande).

      (Translation)
      Yes, the SDR Console software and also the PlutoDVB firmware of Evariste F5OEO drive the GPO0 and GPO1 outputs when you switch to transmission. Both outputs are used because they both switch to transmission when the Pluto is switched on for about 5 seconds.
      Amplifier PTT control - Adalm pluto SDR
      We find two schematics for PTT switching, one based on optocouplers, the other based on transistor and reed relay. I chose to implement the second technique, with a double switching circuit, allowing to supply separately independent 2 outputs. A grouped order will certainly be proposed soon. All details on this page.
      There is another solution, but which I do not advise in view of the risk involved on the Pluto. It is the one which consists in detecting the activity of bit0 of the 12 bits bus of the digital/analog converter. For curiosity, I let you discover this implementation of DH1NFJ on this website (German language).

      1. Bonsoir Christian,
        Merci pour toutes ces informations. Inscription faite de mon côté pour la prochaine commande groupée (PTT Pluto). 73 de Axel FR5GS

        (Translation)
        Good evening, Christian,
        Thank you for all this information. Registration made on my side for the next group order (PTT Pluto). 73 from Axel FR5GS

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  7. Christian,

    Congratulations, for great work.

    Thanks for sharing with the community.

    Jose EA3HMJ

    (Translation)
    Christian,

    Félicitations, pour votre excellent travail.
    Merci d’avoir partagé avec la communauté.

    Jose EA3HMJ

  8. Bonjour Christian,
    Merci pour vos articles qui nous permettre d’avancer sur la construction de notre deuxième station DATV à l’Ile de la Réunion. Nous sommes actuellement actif sur QO100 en bande étroite.
    La station DATV est en cours de construction en suivant à la lettre votre tuto.

    Nous recherchons un système à base d’Arduino capable de mettre off le PA du SG Lab lors d’un SWR élevé et qui serait capable de faire les mesures de puissance OUT/IN. Ceci en utilisant les points de mesures en tension prévu à cet effet. Avez vous une idée si un Om c’est déjà penché sur la question.
    Par avance merci,
    Nicolas Dhiver
    FR4LI

    (Translation)
    Hello, Christian,
    Thank you for your articles which will allow us to progress on the construction of our second DATV station in Reunion Island. We are currently active on QO100 in narrowband.
    The DATV station is under construction following your tuto to the letter.

    We are looking for an Arduino based system able to turn off the SG Lab PA at high SWR and which would be able to make OUT/IN power measurements. This by using the voltage measurement points provided for this purpose. Do you have an idea if an Om has already looked into the matter.
    Thank you in advance,
    Nicolas Dhiver
    FR4LI

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  10. This is a great guide, helped me a lot. Merci!
    Ed PY2RN

    (Traduction)
    C’est un excellent guide, qui m’a beaucoup aidé. Merci !
    Ed PY2RN

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