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Thread ID: 60447	2005-08-02 04:04:00	Improving TV reception	Morgenmuffel (187)	PC World Chat

Post ID	Timestamp	Content	User
377470	2005-08-02 06:52:00	Cant immediately find the info to confirm it, but its likely that TV1 uses the lowest frequency (and hence the biggest "bars" on the antenna). Same in this location, and when corrosion on the terminations and bolts on the antenna get bad enough, I take it down, completely strip it and reassemble with new bolts, having cleaned all mating surfaces with a fine emery cloth. The difference in reception quality on TV1 is astounding afterwards. It has minimal affect on the higher frequencies (TV2,3,4) Your description is one of poor signal strength, but it could be partially or fully the fault of the antenna. If you attempt this remember to disconnect the antenna lead from all TVs inside though. The capacitive effect of the power supply can give quite a whack. Check the quality and condition of the cable as well.	godfather (25)
377471	2005-08-02 07:03:00	I would be surprised it it was RF interference as you say chanels 3 & 4 are fine, I would expect RF to affect all channels The easiest way to isolate the problem is to connect another TV if it is still the same then you know it is not a problem with the TV. It could be a bad aerial connection or cable on one of your aerials as you say you have 2 and channels 1 & 2 are probably being received by the big aerial. Get a test meter out and do some resistance checks of the cable at the aerials.	Safari (3993)
377472	2005-08-02 07:19:00	I have tried 3 different tvs, all the same result, I currently have a splitter on the system (split to three tvs) but it makes no difference if i remove it and just run the cable straight through, and all three cables give the same result basically, I have swapped around everything that attaches to the cable from the aerial and no real difference I havent touched anything on the aerial (apart from retrying the angle), so the only mechanical things it could be are the aerial or the aerial cable, so i guess i'll have to check these the next fine/spare day i have Thanks	Morgenmuffel (187)
377473	2005-08-02 07:30:00	I would be surprised it it was RF interference as you say chanels 3 & 4 are fine, I would expect RF to affect all channels RFI is channel selective and tends to affect low band channels more than high band, hence the problems on 1 & 2 . Unless of course the source is very broadband, i . e a whopping great spark generator, or RFI from the CPU and GPU of a wayward computer in a plastic sided case . The evidence suggesting RFI is the diagonal lines and very regular pattern on screen (ignoring the horizontal streaks for the present) . RFI "mixes" with the TV frequncy to produce a low frequency "beat' pattern . That is what I see in the photo, and to me it look like a computer source, but I could be wrong, the photo is not that good unfortunately . It could be a bad aerial connection or cable on one of your aerials as you say you have 2 and channels 1 & 2 are probably being received by the big aerial . Get a test meter out and do some resistance checks of the cable at the aerials . It has already been tried on rabbit ears, and the effect was the same . It sure doesn't look like snow (very weak signal) to me but remote diagnosis is always dodgy, which is why I suggested trying another TV on that aerial system, and that TV on another system elsewhere to prove the integrity of the TV at least . If another TV behaves in the same way, it is either the antenna or RFI, but if it is stationary or moving bars on the screen, or any other form of regular pattern then it is almost certainly RFI, not the antenna . Can you do another pix Nigel? Put the lights off & don't use flash, and that may give a better picture quality . Assuming it is a digital camera, get close so that the TV screen fills the image with just a small border around it . That should provide enough light for a good exposure . Cheers Billy 8-{)	Billy T (70)
377474	2005-08-02 09:36:00	Has it been fine in your neighborhood lately? If so and the picture is good when it rains, or you water the outside aerial - replace the bolts holding the aerial elements. But haveing said that, the picture you gave is not snow, I have seen lots of TV snow, and that is not snow, there could be snow in there somewhere but first you need to focus on the "RF" type interference. Is your TV very old, as the TV ages the ESR on electrolytics go high and if they in switch mode power supplys can give weird problems. If you have a older VCR with the output on low band (the newer VCR have output on UHF) try to play a pre-recorded tape and lettuce know what happens	ERR (8231)
377475	2005-08-02 10:58:00	I have tried 3 different tvs, all the same result, I currently have a splitter on the system (split to three tvs) but it makes no difference if i remove it and just run the cable straight through, and all three cables give the same result. OK Nigel, sounds like that clears the TV. Now all you have to do is turn off everything that could possibly cause interference except the TV and see what happens. As ERR has confirmed, what we see in your photo is not snow, so it is not weak signal per se, but it could be RFI made worse by weak signal. Weak signal could be due to a faulty downlead, but that seems unlikely because your high band channels are OK. That leaves the antenna itself, however the effect on screen is still that of RFI so maybe RFI generating items in your house are causing the visual effects and if the interference went away, the remaining problem would be snow. "Diagonal sinewaves" are definitely RFI. I assume you have checked that the antenna plug is wired correctly? I have seen more than one plug that looked OK from the outside but the owner had just twisted everything together and bundled it into the top of the plug. Try turning everything else off, expecially computers and the vcr as I suggested earlier, and report the results. Cheers Billy 8-{)	Billy T (70)
377476	2005-08-02 12:43:00	I have tried turning everything off on many occasions but it makes no difference, the picture I took I know doesn't show it well, but it was the clearest out of about 20 photos taken, (with flash off/on lights off/on etc) will try and get a better picture but as of yet that was the best of a bad bunch, and rather strangely tonight the interference was different to normal, if i can't get a better picture, I'll draw a picture of the interference (and if you're really lucky I'll sign it) any way off to sleep for me Thanks for all the help	Morgenmuffel (187)
377477	2005-08-02 20:35:00	Joe, I like this quote, I think its sooooooooooo true :"money can't buy you happiness, but it can help you attain the misery that most agrees with you' lol sarel	sarel (2490)
377478	2005-08-03 02:08:00	TY sarel . . . and more RFI stuff Here in the US when I was a CB nut, we always had trouble with multiples or derivatives of the frequencies we were using on the 11 meter band . CB (Citizen's Band, now called Non-Citizen's Band for all the illegal use of the channels by illegal . . what else? . . . aliens who don't give a fig about "stinking badges or laws" . . I digressed, didn't I?) radio broadcast all around 27 . 125 mhz, and it would selectively blank out or hash up just a few stations . Sorry about dragging my soapbox up again, but I am back now . :waughh: When I would broadcast on my CB, I lost channels 2 and 5 . All the other channels would be fine except for 7 which would get a ghost, but no serious interference . The UHF freqs on the tv were never hit at all . So, what this all means is that RFI can be selective and not affect other things at all . . . . it happens .	SurferJoe46 (51)
377479	2005-08-03 07:13:00	Greetings all Ok I've been on the roof and taken a few photos of the aerial, the connection box looks a bit corroded so i am guessing that could be part of the problem, also got a better picture of the tv screen, (although the diagonal sine wave interference was missing making the picture easier to take) Thanks link here (nigel.geek.nz)	Morgenmuffel (187)
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