15 replies to this topic

[agnagna]

Hi,
Signal ℅ on infobar is wrong.
Value is less than Real....
THX.

[athoik]

Hi,

Osmini has the most accurate dB and %.

Where have you seen that problem?

[MCelliotG]

You must be referring to AGC not SNR, besides there is no point in showing SNR as a percentage, tuners should be able to report the signal as a db value natively and OSmini is a champion in that area (one of the very few).

Edited by MCelliotG, 3 November 2016 - 11:45.

[agnagna]

Hi,

Look screenshot...

 

Value of % on the right under 720x576...is wrong.

 

Until some update ago (I think until 10 october) was ok...

Attached Files

•  shot.jpg   102.61KB   2 downloads

Edited by agnagna, 3 November 2016 - 18:52.

[athoik]

Before some time, development team, experimentally applied the SQI calculation proposed by NorDig specification.

The formula usually gives 100% if the measured CNR is only 3dB higher than the minimum required value of given modulation condition.


Several people complain about "untruth" values, because 100% with only 8dB was strange for Enigma2.

So development team, switched to linear values, that people used to see to Enigma2, abandoning NorDig specification.

So there is nothing wrong

Edited by athoik, 3 November 2016 - 19:08.

[agnagna]

Only for sat I have this bug...
With Terrestrial Signal is 99℅>
THX.

[MCelliotG]

I see the screenshot, if 45% is referred to SNR then yes, it does not correlate well with the 11db reading, 45% is about 7db. My question still remains! Why would anyone use a percentage for SNR, it's non-sensical, and there is a setting to use db instead of %. Certainly most receivers (especially Vu+) do not support SNRdB natively or at all, but Edision OSmini handles this info exceptionally well!

[Erik Slagter]

Percentage is useful though, the problem is that the 0% and the 100% points are not defined, so every manufacturer fills in it's own interpretation. Look at the 0% point, reception often stalls completely somewhere between 0% and 50%, so, then, what does 0% mean? Similarly for 100%, what does 100% mean? Is there an absolute maximum limit to the SNR, not really, so 100% is chosen arbitrarily. Where some manufacturers already reach 100% at 15.5 dB, others only at 18 dB. Then, how accurate is the reading in dB? I don't think it's quite accurate anyway. Manufacturers will always try to show a value as high as possible, because it will suggest their tuners are high quality.

 

So, only compare SNR values between two exact same tuners, then use it for tweaking your dish alignment, for nothing else. And forget the AGC reading, anyway.

[agnagna]

I use motor and Value % is very important to set focus....

If I move motor value % change only when I lost signal (0%) or I find signal (45/52%).

Thx.

[MCelliotG]

On the contrary, db values in decimal (15.2 etc) are way more accurate than % values especially for dish alignments, and since in theory there is no upper limit (contrary to percentages), a db reading is crucial in very strong signals even for comparisons. If for instance one receives a very powerful satellite and has all transponders at 100% it's impossible to know if they have aligned their dish perfectly, for example I have some non 24/7 transponders on the Nordic beam of Thor that I know will only get if some pan European transponders are above 20db with the rest of them above 17db. I woudn't be able to do that precise alignment if I used percentages, since everything above 16db shows me 100%.

But of course anyone can use as they wish.

As for non-sensical, a % value would be practical if all tuners had an upper snr limit that was standard for each manufacturer. Then this way any 100% would correspond to that upper SNR limit with any value between 0-100 spreading evenly to correspond to the SNR scale, and of course that would result to major differences between tuners. In theory SNR shows C/N ratio which should be a boundless value and any dignified tuner should show the same C/N for the same reception parameters with little deviations. In reality this doesn't always happen and different manufacturers handle C/N differently, to the point that it is dubious in some cases if the tuner really shows C/N or something different.

Now, since Enigma2 is implemented to a vast variety of receivers with a broad spectrum of tuners, compromises had to be made, with one of them being 100% corresponding to 16db (as if someone decided that no one will ever be able to receive a stronger signal than this). Several tuners with notably the ones used by Vu+ receivers don't even support db values natively (a driver issue rather than manufacturer issue imo), and it's commendable that the Enigma2 developers tried to make efforts in guessing the corresponding db to the given percentage for conversion. Long story short it's a win-lose situation. Only a very few tuners (like OSmini's) support native and in theory boundless db values and this makes them excellent satfinders for the average users.

[el bandido]

Try changing the source (see attached).

Attached Files

•  User Interface.jpg   116.08KB   1 downloads

[Huevos]

@MCelliotG, of course there is a limit of what the maximum db that can be displayed by the STB. If there were not the signal bar would end at infinity. Whereas normally it ends around 16 or 17dB.

[Huevos]

@El Bandito, that is nothing to do with this. That is to change where fec, snr values, etc, that are displayed on the infobar come from.

[Erik Slagter]

@MCelliotG, of course there is a limit of what the maximum db that can be displayed by the STB. If there were not the signal bar would end at infinity. Whereas normally it ends around 16 or 17dB.

"Normally". But there is no theoretical limit (at least, the theoretical limit will be much higher, but it will only be attainable from space )

[Huevos]

That's why I said 'displayed by the STB'.

[MCelliotG]

@MCelliotG, of course there is a limit of what the maximum db that can be displayed by the STB. If there were not the signal bar would end at infinity. Whereas normally it ends around 16 or 17dB.

Yes, of course, certain receivers do have hardware/software limitations, but in theory C/N is and should be endless and a respectable tuner should reflect that to the maximum of its abilities. A limitation to 16db is unacceptable nowadays given there are quite a few users with slightly bigger dishes and satellites with stronger signals. Spot beams in UK and the Nordic countries can easily go above 20db with a dish around 120cm. All manufacturers should take this into account and provide tuners that support db natively, not the other way around. Even if technically a tuner has a maximum indication, that should end in a much bigger value to reflect a realistic result in all cases. As a DXer myself I cringe everytime for instance a Vu+ user reports a signal of 16.2 or 17db since it's blatant that this signal is not real, it's above that level and we can't know exactly because the tuner limits this ability. Of course not Enigma's 2 fault! Especially OpenPLI team were the only ones that approached the issue as best as possible!!!

Edited by MCelliotG, 5 November 2016 - 11:20.