Freeview - pixelation on certain channels

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wazzab

84 posts

Master Geek

#105340 2-Jul-2012 21:42

Hi there,

I have a brand new Samsung LED, and a two year old Samsung LCD both with inbuilt Freeview. This is my bedroom tv and kids PS3 tv. I have a Freeview UHF aerial running from roof to an 8way splitter, and feeding 8 ports around the house. Both TVs have the same issue and there are only 2 of the 8 way splitter ports in use.

TV1, TV2 U, Maori, Choice, Prime, TV1 +1, etc all perfect, but TV3, Ch4 and TV3 +1 are basically un-watchable and always pixelated with a bit of sound. I thought it was the older model Samsung, so was disappointed when the brand new model did the same thing.

I've isolated the splitter and joined the cable straight through from aerial to the TV, but still the same. Went up on the roof in the weekend, and the aerial is under 2 years old, in good nik, and no sign of any rust or corrosion when I open up the connection box. Aerial is pointed in the same direction as all the other aerials around the neighbourhood.

Is this a tv, splitter or reception problem or any ideas? I'm in Royal Oak, Auckland.

Thanks

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8041 posts

Uber Geek

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#649809 2-Jul-2012 22:12

http://www.freeviewshop.co.nz/type-terminator-plug-p-106.html

Remove any unused legs from the 8 way splitter and replace with these.

Failing that, realistically, ditch the 8 way splitter and get a 2 way one instead.

Basically, yeah, don't leave those legs un attached.

knoydart

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Ultimate Geek

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#649810 2-Jul-2012 22:18

Do either of your TV´s have any diagnostics on them ie display a basic strength and quality meter?

Also do you have any other devices in the set up which may have an RF modulator in them eg VHS players, Sky boxes, xboxes etc?

Finally how old is the cabling in the house?

wazzab

84 posts

Master Geek

#649811 2-Jul-2012 22:21

Thanks for that - if I remove the 8 way, I still get the same result and when I have one join from the aerial to tv. Just been reading Freeview website a bit closer, and see I may be able to aim to Sky Tower and rotate the aerial to vertical - may try that sometime, or also get the big mother 2m long aerial. Just strange that TV1 and TV2 are perfect but 3 and 4 are rubbish.

wazzab

84 posts

Master Geek

#649812 2-Jul-2012 22:32

New LED TV diagnostics report :
Freq : 538000 Khz
Service ID : 04b0
Multiplex : TSID 0019, ONID 222A
Network : Freeview ID 3401
Bit error level : 0
Signal Strength : 65%

Cabling is under 2 years old - all quality quad-shield Maser or Olex cable, with quality compression RG6 connections. I think there is a sky RF modulator in the mix somewhere, as I am able to pick up my Sky channel on one of the analogue channels on the two TVs also.

knoydart

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#649813 2-Jul-2012 22:36

I think there is a sky RF modulator in the mix somewhere, as I am able to pick up my Sky channel on one of the analogue channels on the two TVs also.

Ok I´d pull out the Sky modulator out of the set up temporally, or at least see what channel it (the RF modulator) is set to. Also run your diagnostics set up on a channel on each of the 3 multiplex eg Ch 1,3 & 5 and compare the results between them.

wazzab

84 posts

Master Geek

#649814 2-Jul-2012 22:42

TV1 - perfect picture
Freq : 538000 Khz
Service ID : 04b0
Multiplex : TSID 0019, ONID 222A
Network : Freeview ID 3401
Bit error level : 0
Signal Strength : 65%

TV3 - crap
Freq : 570000 Khz
Service ID : 0514
Multiplex : TSID 0019, ONID 222A
Network : Freeview ID 3401
Bit error level : 515
Signal Strength : 24%

As said earlier, if I run straight through, therefore no splitter or RF modulator, I get similar results - must be the reception then?

knoydart

904 posts

Ultimate Geek

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#649815 2-Jul-2012 22:47

Looks like a local reception issue on the Mediaworks Mux.

Might be time for an installer or at least get hold of some metering to line up the aerial

Edit for poor grammar

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wazzab

84 posts

Master Geek

#649817 2-Jul-2012 22:59

Thanks for that - will jump back on the roof in the weekend, and start yelling at the wife down below, to see if I can improve those Signal Strengths - may also try swinging it round 90degrees and point to sky tower as its pointing west at the moment. Thanks for you help.

sbiddle

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Biddle Corp

Lifetime subscriber

#649820 2-Jul-2012 23:21

One thing to look at would be interference or channel clashes from the RF modulator.

richms

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#649960 3-Jul-2012 11:33

Also if you are down a hill or something and the antenna is aiming into someone elses house virtually then you might find you are getting interference from their system if they have a modulator etc.

At mums place I could quite clearly see what channel the people a couple of doors up were watching on their sky just by tuning into it as there was enough leakage from the shoddy RF cables they supply to get amped up by the massive antenna and masthead amp into something that would sync and be able to make out, with the odd flash of colour. Luckily it was on ch 50something so not a problem for other stuff.

Richard rich.ms

B1GGLZ

1961 posts

Uber Geek

#649964 3-Jul-2012 11:38

Looking at your signal strength figures, therein lies the problem. In your area you should be getting 100% on all muxes. If you are receiving your Sky via an analogue modulator then you definitely have a cabling problem.
Ditch the Sky modulator and run coax from the antenna via 2 way splitter to the TVs. As stated before any unterminate outputs should be terminated with 75 ohm term plug. Run sky to the TVs via HDMI, Component or composite. Using a modulator is the worst possible way to go. You can combine analogue and digital on the one coax but not good and causes problems like yours.

B1GGLZ

1961 posts

Uber Geek

#649968 3-Jul-2012 11:43

wazzab: Thanks for that - will jump back on the roof in the weekend, and start yelling at the wife down below, to see if I can improve those Signal Strengths - may also try swinging it round 90degrees and point to sky tower as its pointing west at the moment. Thanks for you help.

I wouldn't bother with Sky Tower.
I'm on the North Shore and can just see Sky Tower from the roof. I tried pointing at the Sky Tower with a vertical antenna last year and couldn't tune anything on Freeview whilst I get 100% from Waiatarua with a piece of wire stuck in the TV socket. The output power from Sky Tower is very low.

KevinL

656 posts

Ultimate Geek

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#649971 3-Jul-2012 11:46

wazzab: Thanks for that - will jump back on the roof in the weekend, and start yelling at the wife down below, to see if I can improve those Signal Strengths - may also try swinging it round 90degrees and point to sky tower as its pointing west at the moment. Thanks for you help.

I used Google Earth to line up my antenna - find the transmitter you are aiming at, then draw a line from the transmitter to your antenna. Find a landmark that the line intersects (in my case, it was the corner of a house on the other side of the park behind my house) and aim your antenna at the landmark when you are up on the roof. Much easier than using a compass!

wazzab

84 posts

Master Geek

#649974 3-Jul-2012 11:54

This is my current setup - My main TV is sweet - don't use Freeview, just use Sky HDi via HDMI. Two other TVs have freeview, and I use the modulator to get the sky channel I'm watching available on these 2 Tv on an analogue channel

knoydart

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Ultimate Geek

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#649978 3-Jul-2012 11:57

So go direct from the UHF aerial to 1 TV, and see what you get on the Mediaworks mux. Your Sky RF modulator should have a display on what channel it is on, does it say 33 by any chance?

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