texass44 Posted April 24, 2012 Share Posted April 24, 2012 Hi, Digital TV is basically unwatchable tonight in my location, Canterbury Melbourne. The picture is extremely pixelated and no sound. Now I know storms are about but should my picture degrade to an unwatchable state for hours on end ?? I spent $700 plus afew years back getting a dedicated DTV antenna and cabling fixed up. Is anyone else in the same boat tonight ?? Thanks.....Tex. Link to comment Share on other sites More sharing options...
pwd Posted April 24, 2012 Share Posted April 24, 2012 Hi, Digital TV is basically unwatchable tonight in my location, Canterbury Melbourne. The picture is extremely pixelated and no sound. Now I know storms are about but should my picture degrade to an unwatchable state for hours on end ?? I spent $700 plus afew years back getting a dedicated DTV antenna and cabling fixed up. Is anyone else in the same boat tonight ?? Thanks.....Tex. Sounds like your Tv antenna system is not good as it should be, weather should not effect it. You will have to get checked to see if you are receiving a good signal. Link to comment Share on other sites More sharing options...
texass44 Posted April 24, 2012 Author Share Posted April 24, 2012 Hi pwd.....yes, I'd assume weather should not affect the picture too much. I'll have to look up someone with a good rep in our area to check it out !!! Cheers.......Tex. Link to comment Share on other sites More sharing options...
hrh Posted April 24, 2012 Share Posted April 24, 2012 Hi pwd.....yes, I'd assume weather should not affect the picture too much. I'll have to look up someone with a good rep in our area to check it out !!! Cheers.......Tex. Actually weather can affect reception, how much will depend on what the signal strength is like normally. Vegetation in the line of the signal path can affect it, and when it gets wet from rain or other sources that will add to the effect. It won't matter a whole lot how good the antenna is, if the reception area is a low level signal area to begin with anything to degrade the level could be more than enough to tip it over the digital cliff. The other problem could be too much signal strength if the antenna is a high gain one. But as you have suggested a good installer with the right gear should be able to sort it out. Link to comment Share on other sites More sharing options...
alanh Posted April 24, 2012 Share Posted April 24, 2012 (edited) Tex, Were all TV networks affected? Follow http://www.dtvforum....showtopic=11399. There is currently 2 transmitters you can pick from, with a third on the Rialto Tower sometime before the middle of next year. AlanH Edited April 24, 2012 by alanh Link to comment Share on other sites More sharing options...
texass44 Posted May 2, 2012 Author Share Posted May 2, 2012 Tex, Were all TV networks affected? Follow http://www.dtvforum....showtopic=11399. There is currently 2 transmitters you can pick from, with a third on the Rialto Tower sometime before the middle of next year. AlanH Hi AlanH......still suffering terrible picture breakup, Melbourne weather has not been great lately. oddly enough...I still get good reception on channel 31....all others are unwatchable. Time to get the pro's back in I feel. Tex. Link to comment Share on other sites More sharing options...
digital doctor spock Posted May 7, 2012 Share Posted May 7, 2012 Hi Tex I reckon you should get excellent digital TV reception from Mt Dandenong. Weather should not be a huge factor where you are What is your analogue reception like? Do you have trees or buildings obscuring your view of Mt Dandenong? Are your neighbours having digital TV reception issues? What specific channels are being affected? Is Channel 31 digital (44 on your remote) OK? Is your antenna pointing directly at over head power lines? Link to comment Share on other sites More sharing options...
mtv Posted May 7, 2012 Share Posted May 7, 2012 I agree, get your installer back to fix it. Canterbury can be quite variable, from excellent line of site areas, to those in dips with blocked signal paths, so terrain may be an issue for you. Canterbury can experience overloading signals, especially from ABC Ch2 analogue and FM radio, particularly if an antenna designed to receive those frequencies is used. Canterbury can also experience strong reflected signals, causing signal quality problems (seen a ghosting on analogue channels). It's quite normal for weather to affect signals, however, if your digital signals are marginal and wether changes cause signal quality to drop below the minimum threshold, that's when you'll get pixelation and sound dropouts and if it's very bad, complete loss of reception. The key is having sufficient dignal strength and quality above the minimum threshold, so that when levels drop a bit, there is still sufficient in reserve to provide reliable digital reception. C31 digital uses a different encoding method to all other Melbourne channels, making it more robust, even though it's on lower power compared to the others. Given the huge variation of possibilities, having an installer on site with a digital signal meter (with knowledge and experience as well) to determine what the problems are and how to correct them. Link to comment Share on other sites More sharing options...
texass44 Posted May 13, 2012 Author Share Posted May 13, 2012 Massive thanks to all that have chipped in with info.....much apprecitaed. I dont really have clear line of sight to the Dandenogs, but I'm quite high up, not in a dip. Not pointing at poer lines either. When I first moved into the area, I went digital (with a SD stb) straight away due to terrible ghosting on analog. I did not have a dedicated digital antenna, just used the old one which worked fine appart from the odd picture breakup due to interference (fridge open/close vacuum cleaner etc) So I decided to fix it once and for all and get cabling re-done with threaded F connectors and a new digital antenna. The setup was antenna to amplifier, amplifier to 4 way splitter, 4 cables to 4 outlets. Up untill recently, it has been rock solid. However, the bad weather seems to now be causing issues So I decided to get up into the roof to check cabling etc. The plot thickens. Using trial and error during a bad case of pixelitis (all channels bad appart from ch31 ) , I slowly removed/added components from my setup to see what would happen. Eventually, I found that after REMOVING the amplifier the picture was fine. I now had the antenna going directly into the 4 way splitter and all looked good. So now I'm even more confused. When the weather is bad, that is when I would expect to need the amplifier. However, removing it fixed the problem. Is it possible the amplifier is somehow failing and corrupting the signal, particulary during bad weather ? I still havent got around to getting a Pro out, maybe I dont need to now !!! Cheers......Tex. Link to comment Share on other sites More sharing options...
mtv Posted May 13, 2012 Share Posted May 13, 2012 The amplifier is probably causing tuner overload (too much signal) which caused excessive bit errors in the data stream. This creates poor signal quality. Signal quality is not measured by signal strength and you can have poor signal qualuty with excellent signal strength. The fact you have severe ghosting on analogue is a major factor of poor signal quality. In bad weather (wet and windy) if you were watching analogue, you would probably notice the ghosting is worse than in calm, dry weather. This is not the amp 'failing', it's an increase in the multipath/reflected signals causing the digital signal 'quality' to drop below the minimum level required for reliable digital reception. The multipath signals.... those being reflected as well as those edirectly from the transmitter which are seen as 'ghosting' on analogue, corrupt the digital signal, seen as picture break-up (pixelation) and sound distortion. When too many errors happen quickly, the serror correction system in your tuner cannot cope and you get pixelation etc, or if the errors are very bad... total loss of reception. A common mistake a lot of people make (including some so-called professional antenna installers) is that an amp will fix poor reception. The reality is, adding an amp can make the problem worse and/or create new problems, in addition to the original issue/s. In your case, what needs to be done is to reduce the errors to an acceptable level. An amplifier will not do this. The multipath reception is likely to be local terrain/buildings, so the key is selection of the best-performing antenna and it's mounting location. Both of those factors are critical, especially the mounting location. In difficult/marginal reception areas, even moving an antenna mounting location just a few centimetres in any direction, including up/down, can be the difference between reliable reception and no reception. To determine where that 'magic spot' is can only be determined with professional signal measuring equipment (in the hand of a knowledgable and experienced operator). Testing with different antennas over your property will dermine the best mounting location and type of antenna for your location. As per my last post, most of Canterbury has quite strong signals, so you shouldn't need an amp at all for a 4-way split. Without accurate signal measurements, it's imposible to know exactly what your signals are doing, but from your description, multipath signals seem to be the main issue (plus overloading with the amp). Link to comment Share on other sites More sharing options...
digital doctor spock Posted May 14, 2012 Share Posted May 14, 2012 Hi Tex I agree with what MTV said. One way to alleviate ghosting is to use an antenna with a higher gain, higher gain antennas tend to reject echo signals more than low gain antennas. Also I agree that amplifiers easily get overloaded today with 7 VHF channels and 3 UHF channels resulting in lots of intermod which can make having an amplifier more detrimental than useful. I cannot emphasis enough the importance of using high quality cable such as quad shielded RG6. Any unused port on the splitter of course needs to be terminated with a 75 ohm termination. Link to comment Share on other sites More sharing options...
pct tech Posted June 4, 2012 Share Posted June 4, 2012 Hey I agree with mtv I really hate to say it but you probably got a little ripped or the tech who upgraded you didn't have a whole lot of knowledge about digital reception. By amplifying the signal, "in layman's terms" basically increases everything in "strength" so if your problem is low strength, the information being passed through "quality or bit error ratio" may not be readable by your decoding device "stu or tv tuner" so the amplifier can improve this. But if you amplify a signal that is already strong enough for your device to read you risk distorting the information and increasing the "noise" or reflections and any rf radiation from every source in the area. To improve reception to its most optimal the foxtel approved pct connectors have minimal ingress and also they are waterproof so should be used at the balun. Also any saddle clamp wall plates should be swapped out for f-type and make sure the splitter is not the old saddle clamp type. The other thing is, dont put up with it for too long. If your devices are operating close to the "digital cliff" they are working overtime and flat out trying to make sense of the information being sent to get you a picture. Overwork a horse and it'll collapse. Link to comment Share on other sites More sharing options...
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