ABC pixelating - Melbourne, since beginning of last week

[exitguy]

Melbourne East, Lower Templestowe/Bulleen - T2 with 3rd USB Tuner (Bluey)
Suddenly ABC has started pixelating on all their channels. No change to anything, either external or internal since Foxtel installed nearly 12 months ago. Everything was working fine with the 3 tuners available and working correctly - visually antenna looks OK
Have un-plugged and re-plugged internal fly lead + USB Tuner, Re-scanned EPG - same issue persists.
Top Signal bar varies between 0 and 15, Bottom signal bar varies between 48-55.

Anybody had any issues with ABC, or could it be one of the tuners is playing up !!!

[MrQuade]

The signal strength on ABC is awful to the point of failure, which is leading to the drop in quality.

What do the other channels look like.

[IanSav]

Hi Exitguy,

No issues with ABC here in Bayside.

Regards,
Ian.

[IanB]

May be a large bird has displaced your antenna slightly or corrosion has finally gotten to the point of no return.

Your Strength and Quality values are very low. What are the values for the other broadcasters?

[exitguy]

May be a large bird has displaced your antenna slightly or corrosion has finally gotten to the point of no return.
Your Strength and Quality values are very low. What are the values for the other broadcasters?

TB= Top Bar / BB = Bottom Bar - All measurements on the HD channel
ABC TB 4-12 / BB 35-45
TEN TB 18-22 / 55-65
SBS TB 25-35 / BB 85-90
SEVEN TB 60 / 100 (steady on these all the time)
NINE TB 35-40 / BB 90-95

[MrQuade]

Those levels are all very very low.
Any quality value less than 70-80 is going to exhibit pixelation and breakup fairly regularly too.

I'd suggest bad connections or water/corrosion are at play here.

[Paul_oz53]

Those levels are all very very low.
Any quality value less than 70-80 is going to exhibit pixelation and breakup fairly regularly too.

I'd suggest bad connections or water/corrosion are at play here.

+1.

My reception in Sunbury Victoria is 91/99.

A while back I had a faulty BellingLee (plugin) connector that caused serious reception issues on one network due to an open screen connection. My experience matches MrQuade's suggested cause.

[exitguy]

Antenna -> Splitter in roof (1 In, 3 Out) -> Run 1 to Lounge / Run 2 to Study / Run 3 to Spare Bedroom

So after your replies I hooked up the old Topfield TRF-7160 to the Study outlet, re-scanned all channels and let it run for around an hour or so - ABC HD & ABC News were pretty much perfect the whole time, did notice a couple of very small pixelations but put that down to some thunderstorms passing through and heading to Mt. Dandenong. Didn't miss a beat on every channel I viewed. I will do a swap in the lounge tomorrow and see how the 7160 goes there, could be the Run 1 cable/connectors that are causing the problem, so if pixelation persists on the Toppy then I have narrowed down the probable cause. Will keep you advise !!! - thanks for all the advice also.

Don't know if this may be relevant or not, but - we live in last unit of a 3 unit MDU, the front unit had 2 large trees one of which was cut down and removed recently. May be coincidence, but since then is when the ABC issue started - could there be any reason that the tree removal has affected the signal as our antenna was pretty much pointed directly to the tree - aimed at Mt. Dandenong.

[Paul_oz53]

Antenna -> Splitter in roof (1 In, 3 Out) -> Run 1 to Lounge / Run 2 to Study / Run 3 to Spare Bedroom

So after your replies I hooked up the old Topfield TRF-7160 to the Study outlet, re-scanned all channels and let it run for around an hour or so - ABC HD & ABC News were pretty much perfect the whole time, did notice a couple of very small pixelations but put that down to some thunderstorms passing through and heading to Mt. Dandenong. Didn't miss a beat on every channel I viewed. I will do a swap in the lounge tomorrow and see how the 7160 goes there, could be the Run 1 cable/connectors that are causing the problem, so if pixelation persists on the Toppy then I have narrowed down the probable cause. Will keep you advise !!! - thanks for all the advice also.

Don't know if this may be relevant or not, but - we live in last unit of a 3 unit MDU, the front unit had 2 large trees one of which was cut down and removed recently. May be coincidence, but since then is when the ABC issue started - could there be any reason that the tree removal has affected the signal as our antenna was pretty much pointed directly to the tree - aimed at Mt. Dandenong.

Trees normally make reception worse. So, it is not immediately obvious that its removal is to blame for the change in reception. It's not totally impossible though. Sometimes too much signal overloads an input but this is very unlikely except if you're really close to the transmitter. I'd park that theory for now, until all other possibilities are eliminated.

Your strategy is sound. The more obvious weak points are the fly-lead and wall connections. I recall someone discovering the central socket connection on the wall outlet was loose. Crimping it with needle nose pliers fixed it. Behind the wall socket is another candidate: the screw connections may be loose or corroded. Less likely are the connections to the splitter since they're probably f-types.

One thing to be aware of is that 3 way splitters have uneven ouputs - around 3.5 db insertion loss on one outlet and 7 db on the other two. Normally this is not an issue but if you're right at the signal strength margin then it may come into play. Find out if there's a difference first.

[sub3R]

One thing to be aware of is that 3 way splitters have uneven ouputs - around 3.5 db insertion loss on one outlet and 7 db on the other two. Normally this is not an issue but if you're right at the signal strength margin then it may come into play. Find out if there's a difference first.

Yes. I avoid using 3-way splitters for that reason.

@exitguy, you may find some helpful information further along in this topic. Similar issues with a good outcome.

[IanB]

See Digital Cliff!

[prl]

One thing to be aware of is that 3 way splitters have uneven ouputs - around 3.5 db insertion loss on one outlet and 7 db on the other two. Normally this is not an issue but if you're right at the signal strength margin then it may come into play. Find out if there's a difference first.

Yes. I avoid using 3-way splitters for that reason.

I assume you know that 3dB of the 3.5dB and 6dB of the 7dB "losses" quoted there aren't actually losses - they're simply the result of the fact that the available power from the antenna is being split across multiple outputs. Half the signal is 3dB less than the original (10 log 0.5 dB = -3.010 dB).

The imbalance on the three-way splitter is because a cascade of two splitters is used - the first splits the power evenly between output 1 and another splitter, and the second splits that power between the second and third outputs, meaning the outputs are at least 3dB, 6dB and 6dB below the input power. If you're only using 3 outputs of a 4-way splitter, you may do no better. If the unused output is terminated (which I suspect few people actually do), then all four outputs will be at least 6dB below the input power. If the unused output is unterminated, I have no idea what the power distribution will be.

[sub3R]

I assume you know that ...

Yes I do. In the past I’ve pulled a few splitters apart (the metal back is usually easy enough to pry off) & your description is spot on.

3-way splitters are fine providing one is aware of the 50, 25, 25 split. But I like to stick with 2-way splitters mainly, or 4-way instead of 3-way & terminate any unused outputs with a 75 ohm terminator. It makes it easier to work out how much below the antenna signal (or amp) each output is.

I think you are right about few people terminating unused outputs.

[exitguy]

[1] Topfield installed in lounge using all the same cables that were connected to the T2 - Fly Lead, LAN and Optical.
All channels including ABC are perfect, no pixelation with either Live TV or Recordings from ABC or any other channel. Did multiple recordings from a range of sources, times, duration lengths etc.

[2] T2 installed in study using all the same cables that were connected to the Topfield - Fly Lead, LAN and Optical.
Same problem in the study with the ABC, pixelation with low quality/strength for either Live TV or Recordings from ABC but other channels OK

Know the Topfield is not as sensitive as the BW so that is probably why it's working OK. At least I can use it while I get this issue sorted out.

This probably narrows down to either the splitter or antenna to splitter cabling or antenna - l'll get someone in to check it out and provide a solution - anybody got a referral for a good antenna guy in the Doncaster / Templestowe / Bulleen / Heidelberg area ???

[Star6key]

Personally, I've found the signal strength/quality on the T4 to be woeful. I had to connect an antenna amplifier to get a good signal (something like this), and this is in 3 different homes in 3 cities.

I never had this issue with the Toppy 2400.

[exitguy]

May be a large bird has displaced your antenna slightly or corrosion has finally gotten to the point of no return.
Your Strength and Quality values are very low. What are the values for the other broadcasters?

You hit the nail on the head, once the antenna was on the ground you could see is was really due for replacement.
[1] Looks like something definitely hit the antenna as 2 of the rear horizontal bars had been nearly broken off and were just hanging on.
[2] Everything that was not aluminium was corroded and completely covered in rust, just waiting to fall apart.
[3] Balun connectors had corroded so much that it was just a small piece of cable actually connected to the antenna.

Got an antenna guy out
Checked and tested all the points inside, all were not even marginal at best. So narrowed down to the splitter inside the roof or cabling or antenna.
Got up on the roof and took one look at the antenna, said not worth even trying to repair just get it replaced.
So new antenna fitted that is much better built and with LTE filter, new cabling from antenna to splitter, new splitter inside roof, antenna aligned & tested, checked and tested all the inside points that now are showing high strength and quality.
Now getting 95-100 Strength and 80-90 quality on all channels - happy chappie as the T2 is back in action and the "bluey" 3rd tuner actually seems to be better with the increased signal strength !!!