AL9999 Posted September 28, 2004 Posted September 28, 2004 Hi guys, I got a hold of a DigiTV PCI card about a couple of weeks ago and since plugging it into my computer at home have had no problem tuning channels, although I get a rather high BER rating in the technical status window in DigiTV. Channel 7 is the only unaffected channel, but it's bad enough to cause slight pixellation in SBS and Channel 9, and make ABC and Channel 10 completely unwatchable. I have no problems with signal strength and signal to noise ratio however (typically around 75-80% and 22dB). Even on Channel 7 the BER hovers between 0.015-0.02, with ABC and 10 losing FEC lock completely in the end (BER of about 0.06-0.07). I'm located in Prestons in south-west Sydney (near Liverpool), and the DigiTV card is connected direct to the antenna wall socket. The house is only five years old so should have a fairly new antenna on top, although we did need to get a wall power-plug booster plugged in to get any TV reception at all (in both analog and digital's case). I have tested the card in a computer in Balmain near the CBD and not had any problems at all (tested off rabbit ears incidentally), so I don't think the card is the problem, although rather weirdly if I push upwards on the antenna connector on the DigiTV card the BER drops rather drastically and Channel 10 becomes watchable, although it still has a bit of pixellation. Could the socket itself be damaged perhaps? I have tried swapping antenna cables but it made no difference. Or maybe it's the house antenna... It's somewhat annoying as Channel 10 was the main reason I bought the card for Any help would be greatly appreciated
joeybloggs Posted September 28, 2004 Posted September 28, 2004 Yup I think it's about time you got someone to fix the antenna system. More than likely you pushing on the socket is just creating a better signal or ground plane...
murrayt Posted September 28, 2004 Posted September 28, 2004 AL9999 Yes sounds to me like an antenna/lead-in/fly lead problem. Note that in Sydney ABC and TEN are broadcast on Channels VHF 11 and 12 and some antennas were not designed to receive at those frequencies and so the sensitivity can be lower Given you had to get a booster to get even analog sounds like you are starting behind the mark Have a look also at which direction the antenna is pointing. Sometimes in the South West installers can aim the antenna towards Knight's Hill in Wollongong and the transmissions are on UHF not VHF. And also check to see if it is in the roof space that there isn't foil sarking unter the tiles. That will reduce signal strength.
Anarchi Posted September 29, 2004 Posted September 29, 2004 Ok Im also having reception problems, but only with ABC. The strange thing is, sometimes ABC is virtually perfect with only a slight block here and there every few seconds, other times (like tonight at 8pm 29-9-04), ABC gets *extremely* blocky with major audio and visual glitches and is unwatchable, 95% of the screen is filled with green garbage. I dont think its a night or weather problem since its been fine in bad weather, and most nights its ok. All other channels including SBS and ch44 are perfect when it happens. Here are the stats when it happens: ABC (Major corruption) Strength 63% SNR 15dB BER 0.0667 (RED) Seven (No corruption) Strength 73% SNR 22dB BER 0.0158 (Green) Nine (No corruption) Strength 77% SNR 25dB BER 0.0081 (Green) TEN (No corruption) Strength 68% SNR 23dB BER 0.0356 (orange) ch44 (Slight corruption) Strength 35% SNR 13dB BER 0.0215 (Green) Does anyone else have this problem? I live in Sydney (Northern beaches).
murrayt Posted September 29, 2004 Posted September 29, 2004 Anarchi I live in Sydney's South Tonight I have not seen problems with ABC, but I suspect that with the rain showers and cloud etc that reception could be affected My trials with attenuated signals showed that when low an SNR around 15dB was unwatcheable and corresponded to BER's above 0.05. Once SNR is below 18 picture quality falls off and BER increases I guess it is reception quality that is the problem
Anarchi Posted September 29, 2004 Posted September 29, 2004 Hi Murray, yes it does seem to be a reception problem sicne the BER is bad, but what confuses me is that it has also happened when the weather was perfect. I guess there are other factors causing bad reception such as humidity, or a telstra truck parked in front of the ABC transmitter tower I just find it strange that ABC goes from near perfect to a totally unwatchable state. Ill compare the stats next time ABC is ok.. [edit] now ABC wont even show anything - it just stays black every time I try to enter ABC. Anyhoo no big loss since the ABC isnt really my cup of tea...
joeybloggs Posted September 29, 2004 Posted September 29, 2004 Does analog ABC reception track the digital ?
Anarchi Posted September 29, 2004 Posted September 29, 2004 Does analog ABC reception track the digital ? <{POST_SNAPBACK}> Anarchi's dictionary: A~na-lo-gue' - ??? Cant quite remember what analog ABC was like, from what I remember it was fine, SBS was very snowy and now SBS is perfect.
AL9999 Posted October 2, 2004 Author Posted October 2, 2004 Thanks guys for the quick response. It does indeed look like my antenna, Channels 10 and ABC have completely died this morning but the other three channels are no problem at all... I'm just amazed as our house is only six years old, and I would have thought they would have installed a modern antenna in there. Thanks again
gclark8 Posted October 2, 2004 Posted October 2, 2004 (edited) I designed this for Digital + ABC analogue, it is near you. http://www.users.bigpond.net.au/adonai/SYDNEY.JPG I suggest you buy a "digital" antenna (ch6-69) and just use it for the card. I use a Fracrro LP345HV, it requires NO diplexer or balun, just good quality RG6 coax and is readily available from Laceys in Chipping Norton. Edited October 3, 2004 by gclark8
murrayt Posted October 3, 2004 Posted October 3, 2004 AL9999 Around Sydney you should be able to get a combination VHF/UHF antenna from Hills or Matchmaster that will do the job. If you are doing it yourself I found that using UBD on disk and using the distance calculator was handy to draw a line from your house location to the transmitters at Gore hill and Chatswood etc and then using the line to identify local landmarks to line up on. Alternatively have someone rotate it gently and watch for maximun SNR and minimum BER on each of the channels Alternatively you could use a VHF (Ch 6-12) and separate UHF unit combined into a masthead amplifier to give you excellent coverage, to multiple outlets in the home. But be aware that if you still want analog ABC the second method may not give good ABC reception. Many contributors to the forum would recommend using 'quad shielded' lead in cable to get best results. But expense will be the driver mostly
alanh Posted October 3, 2004 Posted October 3, 2004 AL9999, Your problem is the ABC AM radio transmitters which are in your suburb. Do you have problems with ABC radio in your phone? I live under similar conditions. I fixed all my problems with the following set up. Replace your antenna with a Hills DY10 and add an Hills TMX12 9-13 dB for SBS, community TV & datacasting trial. They are connected to a Kingray MHW34F mast head amplifier. All cabling uses quad RG 6 and F connectors. For analog reception I had to add a braid breaker as well. The advantage of the DY10 is that it is designed for only channels 6-12. The dipole where the cable is connected is the only part which can add AM interference where as the log periodics such as Fracarro LP### the whole antenna will pick up AM interference. Also since the above antennas cannot receive channel 2, the dipole is much shorter reducing the amount of interference fed down the centre of the cabling to the receiver. If you still wish to use analog the above set up will give all stations except ABC. Keep your old antenna for this and keep it separately wired. AlanH
murrayt Posted October 4, 2004 Posted October 4, 2004 AL9999 Sounds like Alanh's advice is on the money given his local knowledge My setup is just a bit different in that I used a Hills SF91WB (Ch 28-69, 11.5-18dB) I had one already, and the matchmaster 03MM-DR3018 (Ch 6-12, 14dB) connected to a Kingray MHW34G masthead amplifier. The F version has 'F' type connectors as opposed to screw type connectors (I think). I use a Matchmaster DC23A for the analog lounge TV. The digital fed has a 2 way splitter but I get overall 80% strength 25dB SNR and BER worst case 0.01 down to 0.004 for D44. ABC is about 0.007 typically. I found that given SBS's strong transmit power I had to reduce the variable gain on the UHF side to avoid saturating the tuner inputs. But the results have been well worth the effort
AL9999 Posted October 24, 2004 Author Posted October 24, 2004 Hey everyone, Thanks for the advice given a while back, it's much appreciated. I've let the thing sit for a while as it hasn't been crucial priority or anything. However I decided to fiddle around with my computer (and DigiTV card) again, and I've become more convinced there's something wrong with my card. Remember how I mentioned that by pushing up on the antenna-in connector on the DigiTV card, that SNR and BER values improved dramatically? I understand that if you hold them up yourself you can act as a supplemental antenna, but I've gone and stuck some empty CD cases beneath the socket to achieve the same effect of pushing upwards on the connector, and it's had the same effect of improving the image (although Ten and ABC are still impossible to watch, ultimately it's probably the antenna in this case). All I want to know is if I should bother sending the card back if it's faulty, or if all DigiTV cards exhibit this behaviour. Thanks
Georgea Posted October 24, 2004 Posted October 24, 2004 Hey everyone,Thanks for the advice given a while back, it's much appreciated. I've let the thing sit for a while as it hasn't been crucial priority or anything. However I decided to fiddle around with my computer (and DigiTV card) again, and I've become more convinced there's something wrong with my card. Remember how I mentioned that by pushing up on the antenna-in connector on the DigiTV card, that SNR and BER values improved dramatically? I understand that if you hold them up yourself you can act as a supplemental antenna, but I've gone and stuck some empty CD cases beneath the socket to achieve the same effect of pushing upwards on the connector, and it's had the same effect of improving the image (although Ten and ABC are still impossible to watch, ultimately it's probably the antenna in this case). All I want to know is if I should bother sending the card back if it's faulty, or if all DigiTV cards exhibit this behaviour. Thanks <{POST_SNAPBACK}> Have you tried the card in a different computer? I had a problem with my DigiTV when I first bought it, and it turned out to be the PC power supply (noisy PCI 12V) which the Nebula card uses for the tuner.
AL9999 Posted October 26, 2004 Author Posted October 26, 2004 No, I might give that a try this weekend. The impression I get is that a connector on the board might not be soldered in properly or something. Another thing I tried today, when I run the antenna out from the DigiTV card to my analog TV tuner card, the signal is much weaker than if I run the cable from the wall socket directly. However, if I push up on the antenna-in socket on the DigiTV card, then the analog card's picture improves to the point of being equal to connecting it directly to the wall socket.
AL9999 Posted November 7, 2004 Author Posted November 7, 2004 Hi everyone, I've managed to almost completely solve my problem, using a combination of a antenna splitter booster box, as well as quad shielded cable from the booster to my computer. It's had the effect of making both ABC and Ten's BER drop from 0.07 down to 0.015 on average, and it's increased Ten's SNR from 22 to 24dB. In fact, after playing with it for a while I don't even think I need that booster. It's the quad-shield antenna cable that's made all the difference. Didn't need a new antenna after all
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