Not sat related but...

Discussion in 'TV & Satellite' started by Jaws, Nov 17, 2012.

  1. Jaws

    Jaws Funster Life Member

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    I have two cameras on the back of the van.. One wide angle and one with a 16mm focal length lens which gives ABOUT the same view as an interior mirror would give ( back of the van has a garage in the way for a 'normal' mirror )
    Both cameras go to a 7" split screen monitor on the dash

    After about a year installing the long range unit, I started getting light, travelling up the screen, interference lines which only occur when the engine is running

    So far I have tried ( in order of attempts )

    Swapping the feeds to the monitor but the lines moved as well, so nowt to do with the monitor ( I did think it unlikely but it WAS the easiest thing to try ! )

    Re-wiring the voltage feed to a different point

    Tapping the camera in case it was vibration causing it

    Again altering the 12v feed, this time sharing the feed from the other camera

    and yesterday, spent 2 hours running new pucka low loss coaxial cable from front to back

    Then tried a blocking diode and a couple of caps on the 12v feed and also a cap and L ladder filter on the video feed

    Nothing has made the slightest difference ! ( actually, not quite true.. Replacing the coax has resulted in a much better picture over all when stationary but seems to have enhanced the interference by the same amount when the engine is running )

    I have now ordered a replacement camera ( ones with a 16mm lens at a reasonable price are few and far between ! ) as that is really the only thing left....

    But I would be interested to hear others thoughts and ideas on this problem .....
     
  2. wizzer59

    wizzer59 Funster

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    Suggests that something on the engine is causing feedback, have you added or done anything else recently? what if you turn on ignition but don't start engine, do the lines still appear? if this sounds like I'm some sort of expert, I'm not ok:Confused::Wink:
     
  3. hilldweller

    hilldweller Funster Life Member

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    Do lines vary with engine speed ?

    If not possibly voltage causing it ?

    Maybe a voltage spike zapped the camera a bit.
     
  4. icantremember

    icantremember Funster

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    Must be those new brake pads:Doh:
     
  5. aba

    aba

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    try a resistor in the video signal cable as the camera may have a bit too much gain for the monitor.
    as a signal that is too strong will cause all sorts of problems as will one not strong enough.
     
  6. Jaws

    Jaws Funster Life Member

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    first thing I tried was a 1k r in line but made no real difference,, then I put a scope on it and am getting exactly 1v peak to peak anyways.. And it did work perfectly for the first several months

    And that is the REALLY odd thing Brian.. the speed of the lines does not change with engine revs .. plus the camera mounted right beside it, running from the same dc feed ( and still on the crappy cheapo coax ) is perfect.. no interfence what so ever

    I have been fiddling again today ( was out there running tests on a n other sat system we are going to be putting on Darrells van so once that was done I had another fiddle, swapping all feeds completely and it remained on the same camera.. kinda points to something really weird in the darned camera..

    The replacement is due on Wednesday so will update after I have swapped it out
     
  7. jhorsf

    jhorsf Read Only Funster

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    Anything I would have said to try was well covered in your OP so I am sorry but I have no helpful ideas
     
  8. Jaws

    Jaws Funster Life Member

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    It really is a bloody odd one to say the least

    I was reminded that the seal on the front had leaked a few weeks before the start of the fun and games, but I was sure I had dried it out well before resealing it..

    I suppose it MAY have rotted a decoupling somewhere .. But hopefully replacing the camera will sort it out

    The old camera will not go to waste as I can use it somewhere in my security system here ( with no engines running in the house it should be fine !! :Wink: )
     
  9. sedge

    sedge Funster

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    QUOTE

    After about a year installing the long range unit, I started getting light, travelling up the screen, interference lines which only occur when the engine is running

    UNQUOTE

    Blimey John, so it's been nowt but trouble since you took it out the box?

    :Rofl1:
     
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  10. Traveller_HA5_3DOM

    Traveller_HA5_3DOM Read Only Funster

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    I always like to try the simple things first and I did not notice from your post that you had examined the earth points and ensured that you have a good bare metal contact for the earth points. It is something that tends to get a visual check but really warrants dismantle and strip off any paint from the area.
     
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