Intermittent pixilation on some channels for a couple of weeks

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296 posts

Ultimate Geek

#1627943 12-Sep-2016 15:32

First of all, a few weeks ago everything was fine.

Having said that, I have been streamlining some more today. I was wrong in saying it was an amplified 5-way splitter, it is only 4 way, one is the aerial input, silly me. :)

I now have RF from amplified box going direct to the TV, the Panasonic recorder, Magic TV recorder, and Freeview Plus T2100.

Until today the aerial for the two recorders were coming from a non-amplified splitter from the main amplified splitter. The reason for this is I had tried to use the forth slot as an aerial for my FM radio. Alas, the VHF aerial is gone so this no longer works.

Still getting occasional pixilation, only channel 32. If the theory of deterioration was true, channel 28 would be suffering first but that is fine. According to Magic TV, the TV3 signal is only 97% strength.

It's possible my original problems stemmed from aforementioned daisy-chaining. It was when I added the T2100 to the mix that the problems had begun, but now even if I remove it from the set up, there is still light pixilation, though definitely not as bad.

It's possible there are two separate issues by coincidence. On Wednesday we had quite a storm. I think the aerial may have moved. However, if that is the case, wouldn't all the channels be affected?

Rikkitic

Awrrr
18667 posts

Uber Geek

Lifetime subscriber

#1627961 12-Sep-2016 15:54

Some channels are stronger than others so might not be bothered by an overall weakening of the signal. At least that is how it appears on my set-up. If your reception is right on the edge for any reason, a further decrease of the signal might affect some channels but not others. I experienced this myself not long ago and the problem turned out to be a faulty cable. It attenuated the signal enough to affect some channels, but not all. Some frequencies may also be more vulnerable than others.

Plesse igmore amd axxept applogies in adbance fir anu typos

Rickles

2938 posts

Uber Geek

Trusted

#1627965 12-Sep-2016 16:01

>Still getting occasional pixilation, only channel 32.<

Isn't that Rotorua? Pretty good to get a signal from there in Christchurch?

fe31nz

1233 posts

Uber Geek

#1628006 12-Sep-2016 17:31

RustyViewer:

It's possible there are two separate issues by coincidence. On Wednesday we had quite a storm. I think the aerial may have moved. However, if that is the case, wouldn't all the channels be affected?

No, tuners do not have the same sensitivity over their full frequency range. They are usually most sensitive somewhere in the middle of the range, and less sensitive at higher and lower frequencies. So the channel frequency matters. Also, not all transmitters necesarily have the same power output. I would have expected that at a major site like Sugarloaf that all the transmitters were pretty much the same though, but I can not find any power figures to check on that.

Spyware

3764 posts

Uber Geek

Lifetime subscriber

#1628037 12-Sep-2016 18:03

Sugarloaf DVB-T muxes, on 28, 32, 34 and 36, are all 47 dBW.

Spark Max Fibre using Mikrotik CCR1009-8G-1S-1S+, CRS125-24G-1S, Unifi UAP, U6-Pro, UAP-AC-M-Pro, Apple TV 4K (2022), Apple TV 4K (2017), iPad Air 1st gen, iPad Air 4th gen, iPhone 13, SkyNZ3151 (the white box). If it doesn't move then it's data cabled.

fe31nz

1233 posts

Uber Geek

#1628174 12-Sep-2016 20:59

One thing to bare in mind is that some of your recorder boxes will have dual (or more) tuners. The TV, unless it is a very unusual one that does picture-in-picture with an extra tuner, will have only one tuner. So, how many aerial inputs do each of these devices have? The TV is likely one, for its one tuner. But the recorder boxes also likely only have one input, but feed two or more tuners from that one input. In which case, they will have an internal splitter, splitting the signal up to send it to each tuner. So if there are dual tuners, each of those dual tuners will get slightly less than half the signal strength available at the box's aerial input (slightly less as splitter circuits are not 100% efficient). If there are three tuners and one aerial input, each tuner will be getting slightly less than one third of the input signal. As a result, the TV will normally be getting at least twice the signal level at its single tuner that any of the recorder boxes is getting at any of their tuners. Hence the recorder boxes may struggle with insuffient signal while the TV is just fine. So, how many tuners do each of those boxes have?

RustyViewer

296 posts

Ultimate Geek

#1628184 12-Sep-2016 21:20

I have had no noticeable problem with Family Feud tonight. I have also recorded some of The Edge to check but everything seems Ok for the moment. I think my streamlining has made a difference. :)

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RustyViewer

296 posts

Ultimate Geek

#1638438 21-Sep-2016 23:28

Was quite bad on Family Feud today. The Problem mainly appears to occur late afternoon/early evening. It was raining tonight however which may or may not have accentuated the problem. Is no one else getting this problem on channel 32 stations?

Did some checking re: Freeview news and realised Parliament TV was still on 22 and it had been switched to 31 in July. So I retuned ALL the stations, not just the ones on channel 32, for both my Panasonic recorder and TV. I don't know if that will make a difference though.

SATTV

1649 posts

Uber Geek

ID Verified

#1638491 22-Sep-2016 07:15

You said in an earlier post that you had 97% signal strength, by any chance does it measure signal quality or ber ( bit error rate )

In the digital world the quality is more important.

Having an amplifier can make things worse some times.

I recommend that you get an aerial installer with the proper tools i.e. digital field strength meter to make sure the aerial is in the correct spot.

UHF can be a funny beast, on one site I was on in the back of beyond I had an aerial on top of a 2.5m pole struggling for signal, dropping it down to about 1.5m made the needle bend in the right direction and have signal to spare.

Conversely too much signal can have the same effect and not enough signal.

Without the proper tools you can not fix it properly or reliably.

John

I know enough to be dangerous

RustyViewer

296 posts

Ultimate Geek

#1641521 28-Sep-2016 00:16

I've found the cause of the problem. Unfortunately it is the Dish TV T2100. This is what I had introduced to the mix recently. Even after I disconnected the aerial from the box and it was ONLY IN STANDBY, I still kept getting the intermittent interference. The moment I pulled the power out of the box, things appeared to come right. For the first time, Family Feud had perfect picture again and The Edge also seems fine though I haven't watched it too much. I'll keep my eye on it but that appears to be the culprit. Why would a Freeview plus box be interfering with the aerial signal just by being on standby?

B1GGLZ

1961 posts

Uber Geek

#1641545 28-Sep-2016 08:33

It may have a faulty power supply which is radiating interference. Could also be bad solder joints on the circuit board.

kodiaknz

25 posts

Geek

#1641598 28-Sep-2016 10:46

I have a marginal signal and antenna setup, I get intermittent pixilation with the following:

Children's toys that have electronic sounds being used close to TV

microwave in kitchen being used about 10m away from TV

Peugeot remote key lock when used to lock or open car

Goes to show the number of ways UHF can be interfered with.

RustyViewer

296 posts

Ultimate Geek

#1641978 28-Sep-2016 17:16

It's early moments but I've just tried it with a different power adapter with similar specs to the original. It has appeared to work!

RustyViewer

296 posts

Ultimate Geek

#1647690 8-Oct-2016 14:34

To continue this saga, with the T2100 out of the picture, I am still getting some defects on my TV, so I suspect something isn't quite right with the aerial, it may have gone off direct line to sugarloaf. I noticed it shakes in the wind too. Is this normal?

The original power adapter which came with it (1000amp) made things worse but lowering it to 500amp has removed the problem, though there may not be enough power for things like USB recording which I don't do.

Spyware

3764 posts

Uber Geek

Lifetime subscriber

#1647699 8-Oct-2016 14:44

You give no details re: distance to Sugarloaf, whether you have line of sight or even type of antenna being used. I would remove the distribution amp (no details on that either), assuming you are reasonably close to transmitter you should be able to split 8 ways fine without amps.

Best thing is to get an installer who has a spectrum analyser.

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