Are 12 v digital TVs more prone to electrical interference than larger 240v ones? Ive had 3 now, (1died) used at home and in van and seems everytime u switch on a fan, heater etc they do that digitise thing. Bit frustrating. Two fairly cheap models but one is an Akai.
valiant81 said
10:17 AM May 11, 2020
Hi all;
Digital break up can be caused by a number of things, everything from the incorrect antenna, or off direction, trees, poor quality cable and fittings, too little signal or even to much signal !!. Having the right antenna for the channels that you wish to receive, even sharp bends in the cable can cause problems. With poor quality cable and running that cable close to other cables , both 12 volt and mains can cause problems with drop out and even turning on a light or motor can cause all sorts of drop outs. sound and or picture freeze. Sometimes ferrite beads may help.
Had a antenna job a few years ago before i retired ( early days of digital tv ) and my customer had three other technicians try and sort out his problem with one of the digital channels that he was unable to be received. Plenty of signal and the missing channel was at the antenna terminals. No one had check on the quality of the cable, reception was good before digital and it was only since we got digital that my customer started to have problems.
In the end a complete rewire from the antenna to the splitter and on to the wall plates and fly leads. Everything was replaced bar the antenna and having a look at the coax cable, i found that is was a very poor quality and the shielding was basically foil and 4 strands of fine wire. Replacing with good quality RG6 cable soon had my customer very happy.
STRETCH ARMSTRONG said
04:16 PM May 11, 2020
I agree with valiant81. Another issue with my tv is the result from the sell off of spare digital tv frequencies(700-840mHz) to mobile phone industry. This has resulted in some 4g and 5g interference if you are within one km of a tower. My vans tv arial is pre 2015 so is subject to the this. You can buy a simple LTE filter that stops any boost to these frequencies. I believe jaycar has them.
valiant81 said
12:14 PM May 12, 2020
STRETCH ARMSTRONG wrote:
I agree with valiant81. Another issue with my tv is the result from the sell off of spare digital tv frequencies(700-840 mHz) to mobile phone industry. This has resulted in some 4g and 5g interference if you are within one km of a tower. My vans tv aerial is pre 2015 so is subject to the this. You can buy a simple LTE filter that stops any boost to these frequencies. I believe jaycar has them.
Hi all; Stretch, You are right with the LTE filter and one thing that i forgot to mention. But these filters have to be inserted right after the antenna and before any form of amplification if a amplifier is installed. If installed after a, say a masthead amplifier the amplifier would amplifier the tv signal and the 4/5g signals and could then be to high a level for the filter to remove effectively .The Lte filter would still work, but because of the higher levels would be less effective in removing the interference. The same goes for FM filters.
-- Edited by valiant81 on Tuesday 12th of May 2020 12:18:06 PM
stoney123 said
03:31 PM May 12, 2020
What happens when you play a movie from a usb stick?
valiant81 said
09:26 PM May 12, 2020
Hi Stoney 123; No problems if you are playing movies off a usb stick. It is the digital tuner that is picking up the interference.
Whenarewethere said
09:42 PM May 12, 2020
Is the interference happening if the TV is on a completely separate power supply. IE stick the TV on a separate 12v battery not wired through any part of the vehicle.
oldbloke said
10:02 PM May 12, 2020
USB or DVD player its pervect. Only plays up wnen on dtv . And only if fan heater at home is running.
Or if exhaust fan in van shower is running.
Aus-Kiwi said
10:02 AM May 13, 2020
Try twisting the DC wires ? Or if there is shielded wire ? Make sure its earthed at ONE end . Or the shield becomes a conduit for elect interference .. LED lights can cause issues .
oldbloke said
08:43 PM May 15, 2020
What would twisting the 12v wires do?
Jaahn said
09:27 PM May 15, 2020
Aus-Kiwi wrote:
Try twisting the DC wires ? Or if there is shielded wire ? Make sure its earthed at ONE end . Or the shield becomes a conduit for elect interference .. LED lights can cause issues .
Also fitting an old style ignition capacitor between the power in-put leads might bypass it. Or do all three.
Jaahn
-- Edited by Jaahn on Friday 15th of May 2020 09:29:08 PM
-- Edited by Jaahn on Saturday 16th of May 2020 09:13:24 AM
markf said
12:31 PM May 20, 2020
Getting rid of interference of any type can be an exercise in frustration. Ask anyone who's into amateur radio and they'll almost all have tales of the "day I almost became a drug addled, alcoholic, axe wielding, radio wrecker".
The steps to getting rid of interference are working out what sort of interference it is. Hi frequency, low frequency, impulse, etc. How is it getting into the TV ? Is it coming in via the power cord or the antenna ? And most importantly, where is it coming from ?
There are lots of variables when it comes to chasing down interference - far too many to address in one post. In your case I reckon I'd start looking at the fan that causes the interference when you switch it on. To tackle the antenna system, power cables, etc. is only avoiding the issue. Treat the problem at the source - the fan first.
Bicyclecamper said
04:25 PM May 20, 2020
I have a Tv , on 12 volt,it was originally being used on 240 volt but we got an amplifier and 12 volt lead from Jaycar . Have never had a problem with it since we have had it or c.van, it is an Changhong, or chonhing, or ghang ching, actually don't know what it is, would have to go over to the van to find out what it is, but that is beside the point. The last van and tv we had, I built my own aerial, so it would fold up an pack away easily, it worked like a charm, until we stayed at the Eucla, then we could only get SBS, but we were camped in the bush a bit out of town, so I buried most of the coax cable into the ground by 6 inches, and I got 2 extra channels, I think it stopped a lot of interference. But this does not enswer your question I don't think.
oldbloke said
09:50 PM May 20, 2020
Interestingly. Sometimes after the heater fan at home stops the digitizing continues. If i remove the arial plug from the wall and plug back in the picture comes good.
Aus-Kiwi said
09:34 PM May 22, 2020
Twisted wires act as shield . The earth - wire around the positive + wire .
oldbloke said
11:38 AM May 23, 2020
Aus-Kiwi wrote:
Twisted wires act as shield . The earth - wire around the positive + wire .
Pretty sure the interference is from the arial. But will try that
Are 12 v digital TVs more prone to electrical interference than larger 240v ones? Ive had 3 now, (1died) used at home and in van and seems everytime u switch on a fan, heater etc they do that digitise thing. Bit frustrating. Two fairly cheap models but one is an Akai.
Hi all;
Digital break up can be caused by a number of things, everything from the incorrect antenna, or off direction, trees, poor quality cable and fittings, too little signal or even to much signal !!. Having the right antenna for the channels that you wish to receive, even sharp bends in the cable can cause problems. With poor quality cable and running that cable close to other cables , both 12 volt and mains can cause problems with drop out and even turning on a light or motor can cause all sorts of drop outs. sound and or picture freeze. Sometimes ferrite beads may help.
Had a antenna job a few years ago before i retired ( early days of digital tv ) and my customer had three other technicians try and sort out his problem with one of the digital channels that he was unable to be received. Plenty of signal and the missing channel was at the antenna terminals. No one had check on the quality of the cable, reception was good before digital and it was only since we got digital that my customer started to have problems.
In the end a complete rewire from the antenna to the splitter and on to the wall plates and fly leads. Everything was replaced bar the antenna and having a look at the coax cable, i found that is was a very poor quality and the shielding was basically foil and 4 strands of fine wire. Replacing with good quality RG6 cable soon had my customer very happy.
Hi all; Stretch, You are right with the LTE filter and one thing that i forgot to mention. But these filters have to be inserted right after the antenna and before any form of amplification if a amplifier is installed. If installed after a, say a masthead amplifier the amplifier would amplifier the tv signal and the 4/5g signals and could then be to high a level for the filter to remove effectively .The Lte filter would still work, but because of the higher levels would be less effective in removing the interference. The same goes for FM filters.
-- Edited by valiant81 on Tuesday 12th of May 2020 12:18:06 PM
Hi Stoney 123; No problems if you are playing movies off a usb stick. It is the digital tuner that is picking up the interference.
Is the interference happening if the TV is on a completely separate power supply. IE stick the TV on a separate 12v battery not wired through any part of the vehicle.
What would twisting the 12v wires do?
________________________________________________________________________-
Hi Oldbloke
If the interference is being picked up from the 'air' by the power supply wires then twisting the pair may help to reduce the pickup.
If the interference is coming through the power wires from the DC motor running then fit this from Jaycar; https://www.jaycar.com.au/10a-dc-noise-filter-improved/p/AA3074
Installation information; https://www.jaycar.com.au/medias/sys_master/images/images/9399804297246/AA3074-manualMain.pdf
Also fitting an old style ignition capacitor between the power in-put leads might bypass it. Or do all three.
Jaahn
-- Edited by Jaahn on Friday 15th of May 2020 09:29:08 PM
-- Edited by Jaahn on Saturday 16th of May 2020 09:13:24 AM
Getting rid of interference of any type can be an exercise in frustration. Ask anyone who's into amateur radio and they'll almost all have tales of the "day I almost became a drug addled, alcoholic, axe wielding, radio wrecker".
The steps to getting rid of interference are working out what sort of interference it is. Hi frequency, low frequency, impulse, etc. How is it getting into the TV ? Is it coming in via the power cord or the antenna ? And most importantly, where is it coming from ?
There are lots of variables when it comes to chasing down interference - far too many to address in one post. In your case I reckon I'd start looking at the fan that causes the interference when you switch it on. To tackle the antenna system, power cables, etc. is only avoiding the issue. Treat the problem at the source - the fan first.
Pretty sure the interference is from the arial. But will try that
www.jaycar.com.au/u25-ferrite-voltage-spike-protectors-noise-suppressors-each/p/LF1290