H9 Combo shows incorrect values for Signal and Quality

[dumitru.o]

once i have installed the box and connected both DVB-C and DVB-S2 cables i noticed that whatever channel is selected, the Signal and Quality reported is (almost) the same and has nothing to do with the reality:

- on DVB-C tuner it shows a Quality of 91% and a Signal of about 44% when i have connected the same cable to a Samsung FHD TV where the figures are 99% with 100%. I know for sure that the signal is very good so why does my H9 box says i have less than 50% signal strength ?



- on DVB-S2 i have a dish connected to Hotbird 13 East and it doesn't matter the channel i am on, the box shows a Quality of around 45% with a Signal strength of around 72%. It can t be that all the transponders have the same Signal and Quality (with a difference of 1-2 units) and i know for sure that some of them have less than that, i can also see the channel breaking because of low signal but my box shows the same levels all the time for all channels. My signal is around 50-60% on that transponder but what the box is showing is clearly not correct.



I am now using the OpenVIX image but no matter which image i use (OpenATV, egami, OpenVIX) the figures are the same


is my box faulty? can someone else with a H9 Combo can confirm this behavior ?

thank you

[twol]

You cannot compare SNR across different boxes (or TV‘s) - its in most cases a relative value good for setting up a box only. A few boxes (not zgemma, if my memory is correct) have tuners that have been checked and adjustment figures entered to modify what you see but even there its not really good to try and compare with other boxes

[dumitru.o]

the Signal strength and the Quality are THE most important parameters of a signal. If what the box is showing me have nothing to do with the reality, then i don t know why they are still shown but most important thing is that it s very wrong not to have these figures precisely known. i see a big downside in this.....

[adm]

the Signal strength and the Quality are THE most important parameters of a signal. If what the box is showing me have nothing to do with the reality, then i don t know why they are still shown but most important thing is that it s very wrong not to have these figures precisely known. i see a big downside in this.....

What are the units of quality? What is the box actually reporting ... 100% of what?

Is signal strength the best indicator or should it also include the signal to noise ratio. If all the input signal is noise then it doesn't matter what the signal strength indicates. Again, what is the 100% figure refenced to?

Since the dawn of digital TV no two boxes of any type seem to have reported signal strength and quality in the same way. On some box signal strength needs to be close to 100% to get a reliable picture and on other boxes half this figure is OK. This is probably due to the sensitivity of different tuners - some can pick up a signal from a piece of wet string while others require a highly aligned dish/aerial. I’ve had (terrestrial) boxes where if the signal quality wasn’t 99 or 100% it would result in picture breakup. Counter intuitively too much signal can also lead to problems and some boxes only report up to 100% signal strength, double or treble the input signal level and it will still report 100% although by this time the front end electronics may be overloading.

Possibly the most reliable figure is that from post processing, the BER (Bit Rate Error) figure which ideally should be zero and many boxes report the BER figure.

On any box just treat the signal strength as a general indication about the input. If you have problems external components in the system can be adjusted/replaced and the same general indicator checked to see is the figures have changed. For instance, have the signal strength and quality figures displayed and tweak the alignment of your dish to maximise the figures (assuming they don't max out at 100% and you need an in-line attenuator). In this case you don't need absolute accuarcy beacause you are comparing like with like on the same box.

If you want a true indication of your signal strength and quality then you possibly need to buy test equipment costing many times the price of the boxes you have.

[dumitru.o]

thank you for your answer. I understand your point and i am waiting for my SATLINK WS-6980 DVB-S/S2, T/T2, C to arrive in order to check the actual levels and to better align the dish