AV Cable

Discussion in 'General Electronics Chat' started by RodneyB, Jun 16, 2013.

  1. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
    633
    13
    I am trying to run a video cable to a projector from a dvd. The cable run is about 40 meters. I ran a 0.22 mm cable to see if this is possible. Unfortunately all that happened was the Projector displayed processing signal , cant find signal continuously.
    Is it possible to run a video cable over this distance? I cant understand why mine does not work!
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    For the transport of a video signal, you will need a 75 Ohm coax cable.

    Bertus
     
  3. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    I hate to disagree with Bertus, but the cable required will depend upon the signal in question.

    What type of 'video signal' is your DVD player producing?

    S-Video (4 pin mini din connector)
    Composite video (RCA connector, also called 'phono connector' usually coded yellow)
    Component video (usually 3 BNC connectors)
     
  4. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
    633
    13
    Hi Its a composite video using the yellow RCA connector.

    Thanks

    Rodney
     
  5. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    40m should be OK with a CBVS signal.

    However, there are RCA connectors and leads available for pence that are not up to the job and there are professional grade ones you find on professional grade equipment that cost many pounds. You probably need a good in between. Remember that the RCA connector was originally developed for audio work.

    I don't know about your setup but video-over-ethernet can be a good way to go as the max full spec length of an ethernet cable with plugs on each end is 100m or 300m for direct wiring, but will work beyond that.

    Further thoughts,

    Do the pair work OK on a short cable? I ask this because some player units produce inverted signals relative to that required by some display devices.

    You could also consider an in-line amp.
     
  6. RodneyB

    Thread Starter Active Member

    Apr 28, 2012
    633
    13
    Thank you I will test this all and get back to you
     
  7. Ramussons

    Active Member

    May 3, 2013
    557
    92
    I (re)differ. Connectors are different, but the cable is 75Ω Coaxial.

    Ramesh
     
  8. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
  9. vk6zgo

    Active Member

    Jul 21, 2012
    677
    85
    In TV studios,Composite video is sent all over the place in 75Ω coaxial cable.
    40m is no problem for real RG59 ,although studios usually use a slightly larger double screened cable.

    Some of the stuff they sell as RG59 these days is pretty dire,but even this should work OK if you fit the connectors properly.

    Absolutely the worst cable is the skinny stuff supplied in the AV + Video cables you buy at the places that sell TVs.

    It is just about adequate for audio--until the cruddy moulded RCAs become open circuit.

    Personally,I would suggest you buy some good RCA connectors,& use RG58 cable.
    It has proper copper shielding,a copper stranded inner conductor,is more flexible,& is narrower,so fits the good quality RCAs better.

    OK it isn't 75Ω,but I have used it without any problems,as the mismatch is quite small.

    The better RCA connectors are quite large externally,more like a 1/4" Phone plug,& have decent lugs to connect to,as well as cable clamping.

    In the meantime,check whether there is continuity between the two ends of the cable you are using.

    Short one end & measure with an ohmmeter from the other end,--you should see a short circuit.

    Now,remove the short circuit & test again--you should no longer see a short circuit.
     
  10. vk6zgo

    Active Member

    Jul 21, 2012
    677
    85
Loading...