Pixelation question.

[muddy0409]

We bought a DTV some 4 years ago in Rural WA at just about the time the DTV was activated, at least in a test mode. The first thing I noticed was pixelation on all ABC DTV stations, yheir analogue channels were OK, generally appeared to be on windy days.
Ah-ha I thought, loose connection on the old antenna. Had a new one installed with new cable. Made no difference. The installer said "oh well, we tried, it's probably your location that's the problem."
Not wanting to move location, we put up with it.
2 years later, we moved 600 kM north and lo and behold, same problem. Tried another new antenna and coax with no improvement. Bugger. Put up with it again for 12 months.
Then moved back to the first town, about2 km away from the last house, into newly renovated home with NEW antenna. Still the same!!!!!
After 12 months, moved 3000 kM into rural NSW...Still the same problem.
This would tend to suggest to me a TV problem, huh? But the pixelation ONLY happens to all ABC channels, very rarely SBS and NEVER the commercial channels. But my thinking is that if there was a fault in the signal circuitry, it should affect all stations, unless the ABC signal strength is appreciably lower inside the TV and is therefore affected more than higher level commercial channels?
The TV is a TELEFUNKEN TEL4207 42 inch unit.
Perhaps I should pull it apart and see if there is a signal level adjustment somewhere? I cannot find any sort of service manual anywhere so really don't know where to start.
Any comments or suggestions?
Thanks, in advance.

[mtv]

Difficult to determine without accurate signal measurements, but it's rather coincidental that you experience the same issue no matter where you go, assuming the correct antenna is used for each location and that adequate signal quality is present at the antenna input of the TV.

My first thought.... have you tried another TV or STB?

Perhaps the tuner in that particular TV isn't compatible with the ABC encoding.

The cheap fix would probably be using a STB.

[muddy0409]

I do have a DVD/VCR with DTV capability. I might hook that up tomorrow and see what I get. I'll feed it to the TV in HDMI and bypass the TV tuner.
Intriguing, ain't it.
The other thing I might try is my small DTV that is being used as a computer monitor. Didn't think of that, I only bought it last week.
As far as signal strength is concerned, I don't know where the ABC tower is in this neck of the woods. Perhaps ABCs modulation level is a bit lower than the commercial boys, who knows.

I'll post the results when complete.

[mtv]

With digital, it's signal 'quality' not signal strength that determines signal reliability. eg: BER (Bit Error Ratio) and MER (Modulation Error Ratio).

There are other transmission parameters such as FEC Forward Error Correction and Guard Rate that can all contribute, but any tuner that complies fully with the Australian DVB-T standard should cope OK.

Test with the other tuners you have and report back.

I've not seen a VCR with a DVB-T tuner..... what make/model is it?

Does it have an HD tuner, or just SD?

[Antennaman]

I've not seen a VCR with a DVB-T tuner..... what make/model is it?

Does it have an HD tuner, or just SD?

I've not seen just a VCR with a DVB-T tuner either.

I do have a DVD/VCR with DTV capability

However, I have seen DVD/VCR combos that have them.

Probably a Panasonic DMR-EZ48V or a LG RC689D, both with SD tuners.

The LG is still available.

[muddy0409]

SD? whats that?

Mine is LG

[lsemmens]

Standard Definition as opposed to High Definition

[gordon_s1942]

Some years ago I had a Samsung VCR with a Stereo Tuner that cost me well over $500 at the time as stereo tuners were fairly new.
I suspected there was a problem with the reception not long after I bought it as a friend had the same identical model.
It took time to organise but eventually I was able to borrow his and try it on its own and with mine connected and they were as different as chalk and cheese.
Ok, Back then in Analog I was in a deep fringe area (still am in Digital) so to prove the pudding wasnt the same, I tried mine at his place where he had a translator in clear line of sight and his outperformed mine just as it had here.
At the time a local TV repair shop was run by a very competent technician and he was intrigued by my story and after changing the tuner, he said everything shows as being within parameters but it just was not performing correctly.
As with everything, Stereo tuners became standard and prices dropped accordingly so eventually I bought a new VCR and the Samsung was relegated to being a playback only machine which it did perfectly well.

My problem was ALL channels unlike yours on the ABC only but who knows, The Telefunken may just hate you or the ABC.........

[muddy0409]

Just to show how crazy this is, not a breath of wind today and ABC is perfect!!

[gordon_s1942]

Muddy, you show a location as Gulargumbone so I just had a look at the Myswitch/Digital ready site and gave an address of 10 Breelong street, Gulargumbone and it shows the Transmitter for your area is at 90 degrees (EAST) 54 kilometres away at a place called Mt Cenn Cruaich, supposedly that address is in a 'GOOD' area.
I have no idea how close that address I chose is to your location so obviously there could be some variances in the signal between where I chose and you.

According to the Transmitter information the ABC is on VHF channel 12 Vertical polarity while everything else is is on UHF Horizontal polarity and the recommended antenna is a Dual Polarity Combo type.
One thing that does intrigue me is that come the retune in November, ALL your channels go the VHF between 6 and 12.

If your already having problems now on the ABC, whats going to be like next November?

[muddy0409]

Good shot Gord.
I am 5 houses west of that address, on the corner of Breelong and Castlereagh Hwy, so that should be close enough. I reached the conclusion some time ago that the problem MUST be in the set otherwise it wouldn't (shouldn't) show up in 4 different towns 3000 kM apart??
Rapidly reaching the conclusion a new telly is the answer.

[gordon_s1942]

Muddy. I can see by the map Gulargambone is not exactly shall we say 'City Sized' so if you are within the town limits, any address is as the Real estate Agents say, 'Close to all amenities, schools, shops, clubs, Pubs and recreation.


I live in a small village and one day I was saying to people that unlike the old saying, Blink and you'll miss it, we are so small that you dont have to blink to miss it !!!

Before buying a new TV, is it possible to try out another on your antenna and if it works, then there's the answer but if it plays up, it must be YOU or the Missus but for Gawds sake dont say that in her hearing............

Muddy, think about this, where you were before and the TV had the pixilations, were ALL the TV channels on VHF, UHF or a combination like where you are now because if only the ABC was VHF at the others, this could mean the VHF tuner is 'defective' and could be a major problem when the retuning happens latter this year and all your channels go onto the VHF 'band'.

This is a problem today because you dont know with this LNC system what frequencies are used in locations anymore, you just turn on the TV and it does the rest.
A cheap way around this would be to keep the TV but buy a digital STB (HD) as they sell for around $50 now.

[muddy0409]

Well we ain't that small..we jumped to 502 when we hit town.
Previously we were in Port Hedland and Broome (WA)
I am just waiting for the effect to show up again and I will hook up our spare TV.
Don't know what bands the previous towns were on, but from memory we had the set before Hedland went digital, but there were some test transmissions on digital but I can't recall exactly what was effected and what wasn't, but there were definitely SOME problems. In Broome, exactly the same transmission arrangements with tests etc and the same problems.
Back to Hedland testing still on, (but Broome went digital just after we moved back.) problems still there.
To Gular March last year and still the same problem.
I like your suggestion that perhaps the VHF tuner is crook, that would explain it a lot. Looks like we'll be buggered in November.
Oh well, some things are sent to try us.

[gordon_s1942]

502 ???? damn, thats a CITY, hahahahaha.

But consider the option of trying out a digital STB which as I say are cheaper than buying a new TV if everything else is working ok.
We were lucky here as we had digital running in tandem with the analog channels for at least 3 years before the changeover and basically we didnt have to change a thing as it was the same polarity on UHF as the analog signal.
Very few bothered with trying to receive it as they didnt have all the additional channels as they do now and it was expensive.
The biggest problem was sorting out those areas not covered by terrestrial so they could apply for VAST.

[muddy0409]

Hmmm....curiouser & curiouser..
Well, this evening I hooked up my small TV and the pixelation which had been on the big set showed up on the newer set.
This tells me that the cause is external to the sets.
This begs the question :Is ABC vertically polarised everywhere in OZ? If it is, being in a fringe area, or, as in WA, low signal area, having the wrong antenna could well be the answer.
However, I have not seen a single vertical antenna anywhere in town, so why isn't pixelation effecting everyone else. I will have to ask people if they do have any problems.

[gordon_s1942]

No Muddy, the ABC uses both polarities just as the commercial channels do, I have no idea why this is done.
My main town has 2 translators, both UHF with all channels Horizontal, where I get my signal from all channels are UHF Vertical.

If that pixeling is on 2 different sets at the same time, Logically,according to Mr Spock, it has to be an external problem.

[muddy0409]

Yeah, certainly looking like external.
I'm gunna do a drive around town and see if there are any vertical antennas around.

[gordon_s1942]

Muddy, according the Myswitch site for you location, there has to be or either that nobody watches the ABC.
Having tried it myself to prove a point, I have turned antenna to the opposite pole than recommended and unless your next door to the transmitter, it used to knock the arse out of analog and although I havent tried it on digital, I cant imagine it liking it any better.

[muddy0409]

Geez, I must be bloody blind...Had a good look at my antenna, it's a combined UHF horizontal / VHF vertical. as are quite a few in town.
Most other people I have spoken to also say they have similar pixelation problems on various channels, not just ABC, especially wind related. I have noticed on totally still days, there is no pixelation.
So I'm damned if I know where that leaves me. Guess I'll just hafta put up with it or move to a bigger city.

[gordon_s1942]

Muddy, I know the feeling well.
I just checked the Myswitch/Digital site and it shows that your area goes from a combined VHF/UHF area to ALL channels on VHF but one thing I could not find is the polarity of the retune.

This is something I would like to ask one of our experts like MTV and Antennaman to advise about.

Although you wont see this on your TV/STB tuner is the actual channels the signal is being broadcast on and for you, they will be VHF6, 7, 10, 11, 12.
If I am right, your tuner STB will still show the LCN of 2, 3, 5, 6 & 8 the same as it does now.

The 'Retune' date is shown as the 12th of November but as I say, I could not see what Polarity they are going to use but basically once the 'retune' occurs, the UHF portion of your antenna will be just a waste of aluminium on the end of the boom.

As others are experiencing pixeling, it certainly suggests that it is either from the signal coming out of the transmitter or by the atmospheric conditions between you and the transmitter.

What none of us know is just how far the signal from the 'station' travels before it reaches our TV's, it could be bounced through Microwaves, Cables, Satellites a dozen times and any 'faults' in the actual material or that may occur anywhere in that chain could cause your pixeling.

About 2 weeks ago we lost all the Commercial channels for 6 hours on terrestrial translator either from a storm or circuit breaker tripped, who knows?
Then last Friday night, VAST went black as did several PayTV channes, again cause unknown............

Dont you just love Technology???