RX Problem with Pluto

  • Hello,

    First please apologize if i am posting in a wrong place.

    i hope in an help.

    It is a while that i am encountering problems while receiving the QO-100 satellite. I am noticing that the modulation is not clear but it as if the voice vibrates. I have tried with both programs SDR Console and SDRSharp and both give me the same problem.

    I thought it could be drivers problems or programs settings, i have tried to RX the QO-100's signal with a NEWGEN.RTL2832SDR Stick and the SDRSharp and i have noticed that the the Modulation is clear and without any vibrations as on the Pluto.

    I cannot understand if the problem is actually the Pluto or if it could be something else like fore example the LNB or the LNA.

    I have also made a video that is registered the QO-100's audio but cannot upload it on the forum as it is about 30MB.

    If needed i can PM to how need it to understand the problem.
    Please, Please anybody can help me to solve the problem?

    Thanks in advance for any help that will be really appreciated.

    73's de Enzo IK8OZV


    N.B. Tonight i have made a test:
    i have tried to TX with my Kenwood TS-2000X and RX with the Pluto and have noticed that if i TX in FM so the the

    modulation is clear and understandable perfectly while if i TX in USB, i get the problem above.
    If it can help to understand the problem.

    Thanks once more

  • N.B. Tonight i have made a test:
    i have tried to TX with my Kenwood TS-2000X and RX with the Pluto and have noticed that if i TX in FM so the the

    modulation is clear and understandable perfectly while if i TX in USB, i get the problem above.
    If it can help to understand the problem.

    Thanks once more

    Hi,

    There is no sense to test with FM as you can not see the problem as you describe it. In order to find the source of the problem you must first identify better what the problem is, then try to isolate it and finally to solve it.

    For the first step my proposal is to send with a good source a steady carrier (CW) and see receiving it in Pluto in a zoom mode what you see in SSB Rx. You can post the image here to view it.

    For the second step try to isolate it. For example try to Tx a carrier and receive it . It has the same problem? Disconnect any possible power supplies , connections for possible ground loops. Can you hear the TCXO using a SSB receiver to see if the signal is clean? Do not use the Ethernet adapter if you do so. Replace the USB cable. In the isolation phase you have to find the root cause of the problem. If you can solve the problem anyway, is good starting point to isolate it.

    After isolating the problem you can see what solution you can provide to eliminate it.

  • Hi Enzo,

    I have locked my LNB to a GPSDO. When I switch everything on and the GPSDO has not been running for a week or so, I have a similar effect for a few seconds before the GPSDO is locked to the satellites. (The waterfall looks similar) Thus, to me it looks like an unstable reference frequency.


    73 Jens HB9EKO

  • Hi guys i think it is better to clear all as we cannot get to the end.

    I start from the beginner.

    I have brought The Adlam Pluto from Mouser time ago.

    As i am not clever on SMD and modifications i've sent the Pluto to a Dutch OM that he made the TXCO modify for me.

    Until here all was OK on the RX so i got started to go in TX but for an my distraction i have mad an reversed polarity on the CN0417

    that caused a faulty in the Pluto. It was not even recognized anymore when i plugged in the PC, even no Pc USB connection sound.

    So i called the OM who made me the TCXO modify asking him it he could have a look and eventually fix it. He said to send him all and he would do the best to fix it. He made some test and finally he said that i have killed the communication chip. After a couple of weeks he called me and sending me a video where he said that he has fixed the Pluto and in the video he shows a test made with a a Yaesu FT 847 in 70 cm on FM. In the video he made the test with the SDR Console software and he shows sending the tone from the SDR Console and receiving it on the Radio. As the Pluto was already to him he asked me if i would like to have also the PTT modify and the Anti Jitter.

    I said yes and he done them. He sent me back the Pluto. I have the assembled just the RX part Pluto -> Bias Tee -> LNB on the dish.

    Loaded the SDR Console and tried to find the Satellite signal. Yes i found it but with the problem i've said before with a lot of vibration and incomprehensible. I re called him saying about the problem but he said that there is no problem and maybe there should be problems on my side. As i have said before, i have tried to change the LNB but get the same problem. I have tried to change the SDR Console software with the SDRSharp one but always the same issue. I have tried to delete and re install the Pluto drivers but always the same and finally I have tried leaving all the hardware and software as they are and just replace the pluto with and a NEWGEN.RTL2832SDR stick:




    I get the modulation clear as before the polarity revers on the CN0417.

    Hope this story can definitely understand the problem and what is faulty.

    Thanks a lot for any help

    73's de Enzo IK8OZV


    P.S. if needed, i've made a short video but cannot post it as it is about 17MB. I forgot to say that in DATV it works