Ber/Sig/Snr and what they mean

gav12345

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#1
If you press the RED button then the BLUE button with most images
it will display (amongst other things) three readings, a lot of people misunderstand
these and think the BER is the most important IT ISNT.

BER is Bit Error Rate and bellow 20,000 is better but NOT essential,
i have seen perfectly good pictures with it above 50,000

Sig is Signal strength and of course the higher this is the better,
0 can indicate faulty tuner but i have seen perfectly good pictures with very very low Sig i.e. 30 and less.

SNR is the most important (Signal to Noise ratio)
this is how much of the AVAILABLE signal it can see above the noise,and that is why even with
low Sig or poor BER if it can see enough signal above the noise it will work just fine.

So this MUST be above 55,000,if it is less you will have freezing picture and jerky movement or even no picture at all.
This reading is normally between 62,000 and 64,999.
And you may still get EPG but no picture with low SNR

If you cant get it above 55.000 check your cable feed,
1. with another box if poss
2. make sure there is no physical damage to the cable flattening or cuts, if there is change it try again.

If you havent had it working on this feed you may have an *attenuator in your wall box (see below).
Remember just because your cable modem works does not mean your DBox will.

A splitter and an attenuator are different items, a splitter will have NO db figures on it,
an attenuator will, they can look the same as each other but an attenuator can have 2 outs
(looks like a splitter but its NOT) if it says something like 3db or -6db or the like it IS an ATTENUATOR,
NOT a SPLITTER and should not be used as a splitter or you may get jerky or no picture

Attenuators reduce your signal, i.e.
3db reduces it by half (50%),
6db reduces it by 3/4 (75%)
12db will only leave you 1/8 (12.5%) of your original signal.

So as you can see if you have a
3db Attenuator removing it will double your signal !


hope this guide is ok for you guys

just remember just to add that some boxes dont give the correct readings,
I have had a sagem that worked perfectly which gave a zero Sig reading
no matter what image was on it.


cheers
 
Last edited:

gav12345

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#2
cheers liam i thought it would cut down on the typo to do it all at once

and thats it hopefully no more posting about ber/snr info


cheers
 

mgb

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#7
From wicki.tuxbox.org:
---
BER = bit error rate - the error rate of the current signal - this should be as small as possible (0 is OK ).
SNR = SignalToNoiseRatio - the signal strength in the comparison to the noise - the more highly the better the receipt.
SIG = signal strength - the more highly the better the receipt.
---

The problem is to find a tuner driver which deliver trustable numbers. There is no measuring instrument inside a dbox.
The part about splitters is technical nonsense. Every splitter decrease the signal level, thats a physical law. For a 2-way splitter the signal reduction is about 3db and for a 4-way splitter about 6db.
 

ellie1998

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#8
.

Nice one Gav

You will still get the questions because some people can't be bothered to search.

Maybe one of the mods will make it a sticky ?.

Nice One

Have Fun

.
 

Fergalsworld

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#9
just to add some sagems dont give the correct readings,
I have had a sagem that worked perfectly which gave a zero Sig reading
no matter what image was on it.
 

fermec

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#10
I have a sagem 2x1 that was freezing I had a 6db Attenuator on the end of my NThell cable and was getting a signal of 8000, I have now taken this off and my signal has gone upto 18550: thanks : and it looks like it has stopped freezing.

Cheers Gav for the info this seems to have solved my problem.

Fermec

: thanks :
 

gav12345

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#11
Fergalsworld said:
just to add some sagems dont give the correct readings,
I have had a sagem that worked perfectly which gave a zero Sig reading
no matter what image was on it.
hi m8 i dont know if you missed it but this part says

Sig is Signal strength and of course the higher this is the better,
0 can indicate faulty tuner but i have seen perfectly good pictures with very very low Sig i.e. 30 and less.



cheers
 

Fergalsworld

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#12
Certainly did m8
just so happens i have an appointment at specsavers tomorrow
looks like i need it.
Apologies
Regards
 

jjlee

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#13
BER = 0
SNR = 64000
SIG =0
i have a sagem and these are the results i get how come my sig is 0 but i having a working box get freezing a bit but if my signal is 0 doesnt that mean i shouldnt get anything anyone care to explain
 

Fergalsworld

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#14
The snr is the most important thing and yours is very good.
pop the modem out it might help the freezing.
 

BrianA

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#15
I'm readin this at work and can't w8 to get home to take that bloody Attenuator that I've been using as a splitter off my cable.
Cheers Gav12345,I'll let you know what difference it makes as my Dbox (Sagem) was freezing and losing channels.
 

notanotherone

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#16
after looking at gav12345 thread i checked mine and found it was an Attenuator and not a splitter so guess what ill be ripping that out ,when i bought it they assured me it was a splitter but its going back to them
 

mgb

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#17
Thats the result if technical ignorants botch tuts.
Its not possible to produce an unamplified splitter with no signal strength reduction.
 

gav12345

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#18
A splitter and an attenuator are different items, a

splitter will have NO db figures on it

the splitter 3db is the min you should have but if you have both attenuator and a splitter it is adviceable to remove the attenuator and if your 2 way splitter is higher than the above change it and see if that helps


cheers
 

gav12345

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#20
ATTENUATOR will look something like this
 
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