TV reception problems in Sydney?

[MortonH]

Tonight nearly all my digital channels are pixelated to the point of being unwatchable. Did a retune and have lost channels 7 and 10 completely.

I live in an apartment so can't check the antenna. Just wondering if anyone else is having issues? I'm in Ryde.

Cheers.

[Larryp]

All ok where I live, Morton. Maybe your antenna-have you asked others living in your building?

[noeyedeer]

digital tv seems to do this a lot. I lost all channels for about 6 hours one day and then they reappeared. least with old analogue you could still watch it even if it looked like a snow storm or listen to it when reception had it's moments.

matt

[Barrykgerdes]

Yes get used to it! Now we have digital TV anything that gets the decoder out of sync will do this. However I would have thought your area would be less subject than my area (over the hill and far away) at Kellyville.

If you have an apartment distribution system there could be something amiss with the distribution amp or aerial. Check with your neighbours.

Barry

[MortonH]

Thanks guys. Neighbours all seem to have more interesting lives than me and are out! Will ask around tomorrow if not fixed by then.

[mithrandir]

Barry, if you are happy to do without TVS use the UHF transmitters at Kurrajong. You'll have line of sight to those. They are 170deg off axis to my VHF/UHF antenna pointed at St Leonards and even though I don't use them I still get good signal. Every time I retune I have to delete both Kurrajong and Knight's Hill.

[big_dav_2001]

Hi Morton,
Yep, I'm in Schofields and I'm having the same problems, it's been like that since about noon... I did read somewhere about an X-class solar flare in the last few days, but I guess that would affect everyone... Looks like DVD's it is tonight... :)

Davin

[mithrandir]

Signal has been perfect all day here in Glenhaven. Finally an AFL game has had the right team win.

[ianB]

I frequently get the same problem here in QLD, really annoying, usually i find this happens when it is windy, so much for the digital age take me back to the old days.

[GTB_an_Owl]

we get the same problem here in Terrigal on the central coast and we can just about spit on the distribution antenna at forresters beach (about 3 kilometers away as the crow flies)
different days - different channels
worse when it blows or rains
people we have talked to have put up new antenna's and the problem is still the same

geoff

[Barrykgerdes]

Hi Andrew
So far I have not been able to find the Kurrajong stations. I can't receive any digital TV at "ground level". I need the aerial at least roof height and that presents problems as I can no longer climb on the roof. I did get my son to put up a new aerial for VHF pointing at St leonards and a combined UHF aerial for Kurrajong but had trouble with the masthead amp and after trying for a couple of hours to diagnose the fault by remote control I had to re-connect the old system to the new VHF aerial so I could still get some TV.

Generally I have little trouble with the Digital signals but any sort of electrical disturbance can knock it out of sync this problem is normally quite short lived and the system recovers in seconds.

I would like a table of TV Transmitter sites and channels (frequencies) but so far I have not located one.

Barry

PS I don't have LOS to Kurrajong. there are close houses and the Rouse Hill shopping centre that block the LOS path although this should not be a major problem.

[acropolite]

Most reception problems are caused by poor signal strangth rather than interference. I have a very marginal signal at the shack, but still get good quality visual, I put that down to having a good quality antenna (barbecue grille style) matched to a masthead amp. Without the amp there is nothing to watch. If you don't already have a masthead amp then fitting one may improve matters. Even one of the Hills amplified splitters can make a world of difference if your signal is low. I have excellent signal strength at home but still run a 4 way amplified splitter to feed the various devices in the house. If your antenna is shared within the complex then it's a different story, not sure how you get the complex owner to address the issue.

[JohnOS]

We had the exact same issue. I changed my passive splitter to a
king-Ray active splitter a few weeks ago and it solved the problem.
We have excellent reception now.

[mithrandir]

Barry, the complete list is available from ACMA. The attached file (rename to .cmd) will grab the whole set. You need a copy of wget.exe
I can not physically see St Leonards or Knight's Hill (the Old Northern Rd ridge is higher than our roof) but still get signals from both with only the occasional bit of interference. Kurrajong might be LOS but SWMBO would make life hell if I was to climb up two storeys and then the roof to get to the antenna to check.

[Barrykgerdes]

Hi Andrew
I can get wget (compiled for windows 32) but it does not work in Win 7. This is not a major problem as I can boot XP/2000 in my main computer but not this laptop. However I am not versed in its usage other than it is a command line program. I haven't been able to find what the other program actually does yet. When I get home I will need to look into it.

Barry

[mithrandir]

Strange. I have several native copies of wget that work on Win7 and Win8.1 as well as the CygWin version.
If you look at the script you can get the URLs and download the file(s) directly.
The best choice would probably be http://www.acma.gov.au/~/media/Radiocommunications%20Licensing%20a nd%20Telecommunications%20Deploymen t/Information/zip%20file/Broadcast%20Transmitter%20Excel%20z ip.zip

This one has the table of frequencies at the end. http://www.acma.gov.au/~/media/Radiocommunications%20Licensing%20a nd%20Telecommunications%20Deploymen t/Publication/pdf/TVRadio_Handbook_Electronic_edition %20pdf.pdf

From the horrible URLs you can see why I scripted it.

From your place the Kurrajong towers are at bearing 298 deg true. They transmit ABC30, SBS32, TCN33, TEN45 and ATN48. The first three are Band IV and the last two Band V so you probably need a dual band UHF antenna.
The three around Artarmon are 119 or 120 deg true.
Knight's Hill is 192 deg true.

[Barrykgerdes]

Hi Andrew

I had already downloaded /media/Radio...tion%20pdf.pdf (http://www.acma.gov.au/%7E/media/Radiocommunications%20Licensing%20a nd%20Telecommunications%20Deploymen t/Publication/pdf/TVRadio_Handbook_Electronic_edition %20pdf.pdf) some time ago but could not find the Kurrajong transmitters from the hundreds of other entries. I eventually found what I wanted by working backwards from TEN45. The big problem was I did not know that the service was called "Sydney North West".

To work the table properly you first need to know the answer then you can find the question.

Barry

[pgc hunter]

I was watching a recorded show from a couple of days ago, and it was blacking out and pixelating literally every 30 seconds to a minute. Got so mad I almost threw my beer at the TV.

Otherwise no issues with any of the channels or other recorded shows so hopefully a once-off glitch.

[mithrandir]

They update the files monthly. I was rather annoyed when they didn't update them before SBS moved to VHF channel 7. I could not find the new frequency documented anywhere and had to do a full scan to find it.
Like "Jeopardy"? You often have to know the right question to ask. A search for Kurrajong will find the entry in the "Site Name".
The Artarmon towers are actually closer to you - 25-26 Km vs 34 Km - but the terrain is in favour of Kurrajong.

[multiweb]

This week-end I had to go on my roof to fix some tiles. I don't go up there very often as it's a two storey house so I made the most of it and checked the TV antenna. Prior I had done a retune. My postcode is 2168 and the website said the last retune was scheduled March 18th for the Sydney transmitter and June 8th for the Illawara transmitter. Picked up between 40 and 6o channels no problem. Then I proceeded to rotate the Antenna and my boy was checking the picture. Even rotating it out 90 degrees didn't make any difference which really surprised me. In the end I looked at other roofs and pointed the same way. So does it matter any more? :question:
PS: I do have a powered split box, so all the TV cables are powered.

[MortonH]

Turns out the neighbours below me had a similar issue 2 weeks ago. Someone came to fix the antenna and it was sorted. I dug out an old SD set top box and it has the same issue, so certainly seems to be the antenna.

As someone who knows very little about the technology, I find it interesting that each time I retune I pick up different channels. Until now SBS was perfect, ABC and 9 were there but poor, while 7 and 10 had gone. The latest retunes today are only picking up channel 10 and its sub channels (11, etc) but none of them are watchable. Why so much variability?

[mithrandir]

Marc, it would be interesting to know if you can see the transmitter at the top of Razorback. ABC41, TEN44, ATN47, TCN50, and SBS64. It should be on a bearing of about 214 deg true and the same distance as the Artarmon towers depending on exactly where you are in 2168.
We also have a powered splitter. As almost every room in the house has at least one TV socket the splitter is essential.

[Barrykgerdes]

Signal strength is not so important with digital TV as it was with analogue. Analogue needs a 30db S/N ratio to get a reasonable signal but theoretically a digital signal can be detected with a negative S/N ratio or a signal that is below the noise threshold using a computer process.

However to transmit a digitised TV picture requires a very high level of compression to keep it in the allocated bandwidth and this is where the problem lies. Simplified it means if one bit of information is damaged by some sort of interference the whole "frame" will not decode correctly. I expect some form of Hamming code is used to detect the integrity of the frame and if it fails the whole frame will be dropped. The loss of one frame will probably not be noticed but if the interference is severe enough to damage a high proportion of frames the picture will break up. I am not up to scratch in the digital TV as I have not been involved in TV for 30 years so my knowledge of digital TV is very basic.

Barry

[multiweb]

You're right Andrew. In light of your comments I had a look at the map to see where the transmitters were and it seems that when I rotated the antenna 90 degrees clockwise I was pointing at Razorback which I have a clear line of sight to. Freaky coincidence. Funny enough I've always been pointing in the direction of Artarmon and I get good signal even being in a slight depression so it's not like I have a direct view of the transmitter.