Receiving Qatar Oscar 100 satellite with SDR Console

S'équiper pour la réception du satellite

The diagram

Here is the diagram of the receiving line. It corresponds to one of the ways of receiving the signals transmitted by the QO-100 satellite. It has the advantage of implementing a recent and inexpensive technology, which can be considered to be already equipped with a computer.

As mentioned above, the signal transmitted by the satellite is on 10 GHz, the operation of the head is to convert this frequency into a lower frequency, and therefore more easily usable by the usual receivers.

Overview of the Qatar Oscar 100 satellite reception line


The receiver consists of a dish that focuses the incident signals. In the focal point we will place a LNB television receiver unit. But be careful to choose a LNB (Low Noise Block) with PLL technology (Phase-locked loop also called controlled phase loop). Indeed, LNB satellite with DRO (Dielectric Resonator Oscillator) technology will not be suitable because they have very poor frequency stability. Compared to quartz-based PLL LNBs, DRO is relatively unstable with temperature, and undergoes large frequency fluctuations from +/- 250 kHz to +/- 2 MHz. The PLL LNB will evolve to +/- 25 kHz to +/-50 kHz.

Internal diagram of a satellite LNB

Power supply voltagePolarizationModulation (kHz)OL (MHz)Ku band segment (MHz)Transposed to L-band (MHz)
10 à 14 VVertical0975010700 à 11700950 à 1950
15 à 19 VHorizontal0975010700 à 11700950 à 1950
10 à 14 VVertical221060011700 à 127501100 à 2150
15 à 19 VHorizontal221060011700 à 127501100 à 2150

To operate on the transmission frequency of the QO-100 narrowband transponder, we need to operate the LNB in its low frequency portion. Even if the frequency is lower than the minimum frequency indicated on the LNB manufacturers’ data sheets, the latter will be perfectly suitable. So no need to generate 22kHz, and its power supply will be below 15V to activate vertical polarization. The station power supply you probably already own and which usually supplies 13.8V is therefore perfectly suited to power the head via the T-Bias.

Get the LNB PLL heads

As mentioned above, it is important to choose a PLL LNB. Here are some links that are worth completing as we go along.

T bias power supply

The T-bias is designed to inject direct current into the RF circuit without affecting the RF signal. You can find them all made up or you can of course build them up.

The K6VHF software allows you to calculate the necessary capacitors and inductors.

SDR hardware

Le signal va être réceptionné grâce à un “récepteur” SDR (Software Design Radio), qui va transformer le signal en échantillons numériques qui seront récupérés par l’ordinateur. Si vous souhaitez plus de détails sur le fonctionnement des récepteurs et émetteurs SDR, je vous invite vivement à écouter The signal will be received through a SDR (Software Design Radio) “receiver”, which will transform the signal into digital samples that will be collected by the computer. If you would like more details on how SDR receivers and transmitters work, I strongly invite you to listen to Sylvain F4GKR’s presentation which is available on the REF-info channel on Youtube (in french).

There are many hardware solutions, but the most well-known and cheapest is the one that consists in using a USB stick for DVB-T reception, such as this one equipped with an RTL 820T2 chip.

8 thoughts on “Receiving Qatar Oscar 100 satellite with SDR Console

  1. Un grand bravo pour la qualité pédagogique de cet article à la fois synthétique et complet. C’est donc avec impatience que j’attends son équivalent pour la chaine d’émission.
    Merci pour ce travail.
    F8GHE Christian

    Congratulations for the pedagogical quality of this synthetic and complete article. So I look forward to its equivalent for the transmit line.

    Thank you for this work.

    F8GHE Christian

  2. Bonjour,

    Bravo pour votre tuto du coup je maitrise mieux SDR-CONSOLE qui est le meilleur qui soit
    merci encore
    73 de Jean-Maurice F1RXF


    Congratulations for your tuto so I have a better control of SDR-CONSOLE which is the best there is
    thank you again
    73 by Jean-Maurice F1RXF

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  4. Bonsoir,
    super papier et bravo pour ceux qui n’avaient pas encore installé la “synchro” !!! attention à une chose, le décalage de la tête …qui n’est pas le même pour tous ! pour ma part je dois rentrer 9.749.852 pour pouvoir avoir le bon calage… 73 Maurice F6CIU

    great paper and well done for those who have not yet installed the “synchro” !!!! watch out for one thing, the head shift…which is not the same for everyone ! for my part I have to go in 9,749,852 to get the right adjustment…. 73 Maurice F6CIU

  5. Bravo pour tout ce travail de défricheur de solutions qui se révèlent extrêmement performantes et la clarté du propos, particulièrement précis pour l’installation des composants tant matériels que logiciels. F6CNG Olivier

    Congrats for this great work discovering components both hardware and software with great performances and for the complete and clear user manual to install all parts with enough explainations to understand why all the steps are important.

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  7. Bonsoir Christian,
    Super Tuto, ;0)
    A + pour un autre QSO sur OSCAR 100 :0) 73,
    F4FPQ Thierry

    Good evening, Christian,

    Super Tutorial, ;0)

    Soon for another QSO on OSCAR 100: 0) 73,
    F4FPQ Thierry

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  9. Bonjour et merci pour ce superbe article que je vais mettre en œuvre.

    Une question reste en suspend:
    quel est le type de connecteur sur la Clé USB de réception TV TNT ?
    C’est pour commander le bon raccord entre la clé et le T-Bias.


    Hello and thank you for this great article that I will implement.

    One question is still pending:
    what is the type of connector on the USB stick for DVB-T TV reception?
    This is to order the right connection between the key and the T-Bias.

    Thank you

    1. Merci Stéphane pour l’intérêt porté à mon blog.
      Sur le modèle de clé TNT en photo, il doit s’agir d’un connecteur MCX femelle. Je vous laisse vérifier, cela pourrait varier en fonction du modèle.
      Il existe des adaptateurs, tel celui-ci : MCX mâle / Fiche F femelle ou si vous préférez MCX mâle / Fiche BNC femelle

      Espérant avoir répondu, souhaitant un bon montage de votre station de réception de QO 100 !

      Thank you Stéphane for your interest in my blog.
      On the TNT key model in the photo, it must be a female MCX connector. I let you check, it could vary depending on the model.
      There are adapters, such as this one: MCX male / F female plug or if you prefer MCX male / BNC female plug

      Hoping to have answered, wishing a good assembly of the QO 100 receiving station!

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