Unable to Receive DVB-S2 signal from Es'hail 2/QO-100

  • Hello

    Good day to all. I have been receiving SSB(NB) voice from QO-100 but unable to receive DVB-S2 signal.


    My Setup

    --------------

    1: SDR#/SDR Console

    2: 65 CM DTH DISH (offset)

    3: RTL SDR BLOG V3/SDRPLAY RSP 1A

    4: Bias Tee

    5: USB to 12 V DC-DC boost cable

    6: 19 V Laptop Power Adapter

    (One for V and other for H modulation switching)

    7: Connectors

    8: LNB 40 dB,LNB 70 dB

    9: Generic DVB-S2 Receiver KOQIT Mini

    10: MiniTouner Express


    11: My location is Bangalore, India



    Azimuth

    260 Deg

    Elevation

    30 Deg

    Skew

    73 Deg

    The SSB voice reception is good but i am unable to see DVB-S2 spectrum on the SDR program(while using SDRPLAY RSP1A).

    The polarization switching is done by feeding 19 V to LNB via bias tee. Even after feeding 19 V , i could see only NB signal not WB signal. I tried HW and sw decode (leandvb@pabr,DVB-S GUI@Marko) of DVB signal (though it does not make sense)


    I am not sure what i am doing wrong. Could some one help.

    Best Regards

    Priyasloka/VU3BCN


  • VU3BCN try it please with your minitioner express.. this should work.. use the minitioner v0.9 software from Jean Pierre. If you do not have it.. drop me an email at call@darc.de then I can send it to you.. and if needed we can also start teamviewer and then we can solve it together..:thumbup:;)

  • VU3BCN ...

    Hello, did the sprectrum of the SDR signal change in any way if you switch from V to H polarisation?


    Your screenshot looks like you still receive only vertical.


    73s de Robert


  • Hi,

    In the above screenshots what was the bandwidth selected?
    You must have bigger than 2.4MHz bw in order to see the Wideband spectrum signals.
    The attached screencaptures were taken with a similar setup 60cm dish, Octagon Green LNB, ADALM Pluto 8MHz BW and SDR-Console.

    73 de
    CT2IRJ

  • The bandwidth is 2.4 Mhz .

    with 12 V via Bias Tee

    with 18 V via Bias Tee

    The SSB signal is not getting reduced when applied 18V, in fact signal is getting boosted.


    I have not applied skew angle (for my location in Bangalore ,it is 73 deg). Probably

    1: i need to manually rotate the LNB and find the point of maximum and minimum signal. The minimum SSB signal point can be H . Probably voltage switching is not effective or as i have not put skew angle (i have set to 0 deg ) as required , the result is non -reception of DVB signal.


    I have SDRPLAY RSP2/RSP1A,PLUTO SDR and Minitouner, but without proper setting SDR would not much of help. Let me manually rotate to find V,H settings and then look for spectrum in wide band using SDRPLAY or Pluto SDR.

  • Hi, it is normal for 73 degrees to see stronger signal in the other polar as you put it at 0 degrees. I propose to you to adjust range and offset sdr# settings so you can reduse displayed noise and beacon level is a little bit less than maximum.

  • VU3BCN ok.. I think this you also will fix pretty soon. If everything works with version v0.8.. then you after that can also use v0.9 very easy.

    USB3.0 is highly recommended for gettting a good I2C rate from the minitioner express to your computer.:thumbup:;)

  • VU3BCN if I put my lnb into the dish original 90deg. I get the beacon with a mer of only 3.. if I turn it to the skew angle which fits best I just get a mer of more than 7 with just turning the lnb the right way..:thumbup:;)

  • thanks everyone, able to get the beacon temporarily, Minitouner is excellent.

    Appears my dish has physical damage after thrown away by strong wind, the focus has shifted. if i change the focus by bending the LNB support rod, i am getting >5 db C/N, if left unforced the C/N is coming around 1.9-2.5 dB


  • VU3BCN The skew is best adjusted for minimum signal on the wrong polarization (so for DATV switch to H and null the narrow band transponder). Polarization discrimination between H and V will be in the order of >20 dB or so, used in (broadcast) transponders which transmit on the same frequencies but with different polarizations to maximize capacity.


    Although QO-100 hasn't overlapping transponder frequencies (and thus no interference from the other polarization) the effect of having the -super- right skew will be minimal (unless it's the opposite polarization ; -)