Digital TV noise

I get digital noise, mostly on channel seven, at different times. just checking the 'report' from the STB it says: quality- 100%, signal- 64%, S/N ratio- 32db. so how good are these figures? obviously quality is not a problem. what determines quality anyway? thanks,

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rgds,

Pete
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Reply to
felix_unger
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Pretty much useless figures unless the std is known , however it indicates the signal is well above the noise so would be watchable

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Reply to
atec77

Pay attention to what you're replying to.

Reply to
Wolfgang Wildeblood

Reported "quality" is a rubbery number related to decoded bit error rate. At 100% it infers effectively zero decode errors, which doesn't really fit with noise causing an issue.

Question time - are you seeing those numbers at the same time as the noise is present? If so, the STB reckons all is good at its output but the downstream teev is bitching. What does that tell you?

Reply to
who where

yeah it's fine except when it's not.. :)

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rgds,

Pete
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Reply to
felix_unger

Which is normal with digital now can you think of a commonality when it happens we have channel 44 problems with certain overcast conditions and serious storms not that it matters unless gasoline is on

I should suggest once timing is established a house survey be done and any interfering wall warts or electrical devices be audited

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Reply to
atec77

No those are the figures when the picture is fine. I will try to get some when the pic is bad. btw I have several digital FTA devices including the Telstra T-Box, and believe it or not, it handles interference rather well. what local devices could possibly cause interference with the digital FTA transmission? the noise often comes between 4:30 and 7:30, but at other times too of course. I have a good antenna system set up, but my four way splitter amp is plastic (Kingray) and I wondered if the interference could be getting in that way, and if a metal one would be superior in that regard? any recommendations? also notice the interference comes more during wind, storm, and heat! but I removed the (fringe area) antenna dismantled and cleaned all the element connections and redid the cable connection. that boosted the signal level a bit. this was about 12 months ago now tho.

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rgds,

Pete
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Reply to
felix_unger

felix_unger wrote

transmission?

Nothing should do.

Thats suspicous.

But it may have a fault.

interference could be getting in that way,

Unlikely.

See if you ever get the problem without it.

See above.

So you may have a fault, a poor joint somewhere.

connections and redid the cable

But may not have fixed the fault.

Reply to
Rod Speed

felix_unger wrote

Presumably you mean pixellation.

S/N ratio- 32db. so how good are these

That quality 100% is dubious.

Its a digital thing.

Reply to
Rod Speed

"felix_unger"

** Is that "7 Digital" on VHF 177.5 MHz ?

Are you in one of the capital cities?

You must describe what the "digital noise" looks like too.

.... Phil

Reply to
Phil Allison

yes

melbourne, outer suburban

picture and sound break up. pixilation

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rgds,

Pete
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Reply to
felix_unger

** For how long ?

Just brief bursts of "noise" or continuous ?

.... Phil

Reply to
Phil Allison

"Petzl"

** Campbelltown is 53kms from the transmitters at Artarmon and there is high ground between.

Consider yourself lucky to get any UHF signal at all.

Try using a 3 metre long UHF Yagi on a 20 metre high mast.

VHF should be OK with a fringe area antenna too.

... Phil

Reply to
Phil Allison

I can have good signal level and quality, and getting a good picture, but when there is interference present the interference gets to a certain level and suddenly the digital TV signal strength and signal quality just fall off a cliff and head towards zero. The picture and sound either just disappear or are completely unwatchable because of picture breakup, sound gone, etc

Digital TV works well while it is working, but there is no gradual degradation with increasing interference, it just suddenly stops working altogether.

I'm in a reception "black spot". High voltage powerline insulator breakdown is a problem with hot, dry North winds. Cars with "hot" unsuppressed ignitions are a nightmare for reception.

(On that note I've seen a "hot" ignition car put wide rolling bands of noise all over the SBS analogue signal. Talk about a high powered spark transmitter! _All_ the digital TV was just wiped out with this car, which for a time belonged to the lad next door.)

Ross

Reply to
RMD

Just as an addendum, I've recently replaced a general VHF channel 2-12 aerial with a log-periodic Channel VHF 6-12 antenna.

My old VHF aerial had pretty poor signal strength up at Channel 11-12 (where digital 2 and 10 are located), and the new aerial has vastly improved performance on these two channels, which are much more reliable now

It is 39C today with a north wind but there is no power-line interference today, and reception on all digital channels is perfect.

Ross

Reply to
RMD

RMD wrote

Thats just plain wrong.

Reply to
Rod Speed

I just ran "setup" and those Digital above vanished entirely but get 9 on Analogue? I will when I feel need arises just call a TV antennae/aerial guy they should know. Not keen on getting on roof myself

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Reply to
Petzl

In that case, it might be the area. I often loose 9 & 10 grp. now 7, 9,

7 10 groups of channels.

Naah, if I'm at roof top, I have line of sight, but freznel affects might kick in.

Same area. The longest UHF TV aerial from Jaycar combined with something like this

formatting link

Current combination is about 6m from ground.

Thank you for the technical assistance, but frankly, give the general content on TV these days, I would find it hard to invest the time, effort and money in researching a suitable mast, then gaining council approval, then installing it.

Bit cloudy and snowy at time, but far more reliable than the digital channels.

Reply to
terryc

I don't do that. Just put two backets onto peaked end of house(not barge board) and then put both aerials on top of a piep of thin pipe and lifted it up and clamped to the brackets. By "lift", I meant used and acro prop actually.

Reply to
terryc

That's my thinking a new Aerial (I can see Centrepoint on a clear day) Just can't yet to be bothered

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 Petzl
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Reply to
Petzl

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