Re: QUAD Inverto Black Ultra LNB


Hello Ernst,

Thanks for your comments and diagrams.

I tried the 'other receivers' switch on again last evening when my SNR was a little higher and the Strong Viaccess receiver I use for French TNSAT TV, Eutelsat 9B for EbS and Astra 1 German TV channels sometimes but not always caused a small increase in Tellicast Missed Packets before FEC.  Most of these missed packets over time were/are never FEC recovered.

Also the SR1 readout showed increases in errors some of the time.

My SatPal spectrum analyser seemed to cause 'problems' more of the time when switching on at this time. 

But, these missed packets never seem to be a 'visible problem' as I do not see missed data gaps in my images.

>If I understand your first post right you were able to disturb the SR1 via a TV cable ON/OFF that runs >apart from the EUMETCast SR1 and Spectrum Analizer cables.

Yes that's right.
My satellite TV receiver is fed by a cable from another dish and LNB for Astra 1 French and German TV [this cable runs for a length in a plastic tube together with the SatPal cable and EUMETCast cable from the quad LNB] the third cable from the quad LNB runs on its own to the satellite TV receiver for Eutelsat 9B EbS.
The Astra 1 cable and the Eutelsat 9B cable are connected to the satellite TV receiver receiver via a hi isolation coax switch.
Yes I know, I should use a modern DiSEqC switch.

And yes, I too have seen a few missed packets occasionally when switching off 'another receiver.' 

Oh no!
I've just switched on the satellite TV receiver (from the EUMETCast quad LNB) with rain reduced SR1 SNR and no change in Tellicast missed packets!
Both rebooting the receiver and/or switching the antenna coax.

But switching on the SatPal spectrum analyser did cause an increase in BS lost packets (and increased FEC recovered packets!) but not in HVS-1 lost packets.
I switched the SatPal on again and no increase this time in BS (nor any in HVS-1).

I'm not sure I'm proving anything and maybe it's all a coincidence?

Best wishes,


-----Original Message-----
From: Ernst Lobsiger via <ernst.lobsiger@...>
Sent: Mon, 17 Aug 2020 20:37
Subject: Re: [MSG-1] QUAD Inverto Black Ultra LNB

Hi John

Thank you for your experiments and detailed description of your system. It could well be that we see the effect only with lower SNR when everything is more easily disturbed.

If I understand your first post right you were able to disturb the SR1 via a TV cable ON/OFF that runs apart from the EUMETCast SR1 and Spectrum Analizer cables.
So this excludes a cable to cable induction which is even less likely when the cables only run 4.5m in the same tube. This should also test negative with your ASTRA TV.

Your system is good for a couple of more combinations to nail the culprit down. Maybe Ian can repeat his experiment so we can truly exclude the TWIN LNB from consideration.
In any case it must be certain, that at the moment you do the ON/OFF switching of a second receiver, the TELLICast receiver must download data of a subscribed channel.

Looking more closely at the problem today, I even see missed packets when the second source is switched OFF. I had the TC client renamed/rearranged on receiver Europa.
For that I had to take Europa down for a couple of minutes and also unload the DVB-Interfaces in GNU/Linux which will stop tuning and powering the respective LNB cable.

This disturbed receiver Titan on HVS-1 and HVS-2 with missed packets both when OFF and ON at Europa. The basic service on Titan was not affected. See my plots below.

Best regards

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