Re: EUTMETCast DVB-S2 Unable to lock

Ernst Lobsiger

On Tue, Sep 1, 2020 at 08:27 AM, David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺 wrote:

In the report, Transport Status should be Locked.

You should be seeing the RX status alternate between:

EUMETCast DVB-S2 1513.000 MHz, DVB-S2 16APSK 2/3, 32.993 Msps, ACM, 12.1 dB
EUMETCast DVB-S2 1513.000 MHz, DVB-S2 8PSK 3/5, 32.993 Msps, ACM, 12.0 dB

> I swept about 60 degrees around South. Three were on the edges of that angle window, one was close
> to the theoretical direction estimated via + landscape reference. This method  is a good
> start, but I found it difficult to visualize a central axe on the dish to aim at those references in one view.

No need to sweep around 60°. You have to point your dish better than 1° in azimuth and elevation.
If you can stand behind or at the side of your dish you can aim with a homebrew big 90° triangle or
even a plate of styrofoam or stable cardboard that you lay accross the dish. Se the TOP VIEW below.

Azimuth pointing (hope this remains readable):

             / ¦               ¦
           /   ¦               ¦
          ¦    ¦  styro-    ¦
          ¦    ¦   foam    ¦
           \   ¦               ¦
             \ ¦ 90°        ¦
eye   _ _ ¦ _______¦ _ _ _ _ _ >>>> to landmark

> Although I realized afterward the 22KHz was ON during my azimuth scan, with a tuner frequency set
> at 1512.500MHz, I saw the demodulator frequency offset dropping when I desabled the 22KHz, SNR
> increased, and the signal status remained on "locked". So I guess this is not a problem.

You are too lazy here as well. The 22kHz ON makes the multiswitch of your Universal LNB select
the High Band (11700 - 12750 MHZ, Local Oszillator at LO = 10600 MHz) while with the 22kHz
tone OFF you are in the Low Band (10700 - 11700 MHz, Local Oszillator LO = 9750 MHz). This is
more or less like black and white even if you might find a lock of different (!) transponders
in both bands. The same is true for 14 V or 18 V that will switch between V and H polarisation.

All I can recommend is take the right EUMETCast T1 profile (that will set 18Volts and 22KHz OFF).
Make it lock at the very azimuth and elevation dishpointer calculates for your antenna position.

> Transmission Standard is correct (DVB-S2), modulation is correct (8PSK), code rate not exactly
> (3/4 instead of 3/5), but it was varying a lot in the beginning.

You should exactly see what David told you. It must be either 3/5 or 2/3 not 3/4 and ACM not CCM.

With your indications of Modulation, Coderate, 14 or 18V, 0 or 22KHz, Symbol rate (Msps), ACM/CCM
you should be able by now to find on or what you actually receive.



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