Register

Welcome to the RDI-Board Community.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed.


Donate Now Goal amount for this month: 100 EUR, Received: 100 EUR (100%)
Donate to support this site...

Page 1 of 2 12 LastLast
Results 1 to 15 of 30
  1. #1
    Member Mentor
    Join Date
    May 2006
    Posts
    503
    Posts Thanks / Likes

    Default video attenuation


    sorry if this isnt appropriate for this forum,,,but i am hopeing a member can help,,,
    my dreambox is connected via the rca outputs to a "video sender unit".the problem is that the signal is way too strong after it is transmitted,causing contrast and brightness problems.
    there are no variable resistors (trim pots) in the transmitter or receiver that i can use to attenuate the signal.
    does any member know of a simple way to MAKE an inline attenuator
    or a link to an appropriate forum would also be appreciated,,,thnx,,,dave

  2. #2
    Junior Member Friend
    RDI - Board Default Avatar

    Join Date
    Jul 2004
    Location
    malaysia
    Posts
    36
    Posts Thanks / Likes

    Default

    davidss1,
    hi there , u should use a rca to a rf conveter, it works fine,
    there is a scart provider in this conveter and used that for audio or just
    straight rf out to tv tuner on uhf .
    rdg

  3. #3
    Member Mentor
    Join Date
    May 2006
    Posts
    503
    Posts Thanks / Likes

    Default

    Quote Originally Posted by amrit View Post
    davidss1,
    hi there , u should use a rca to a rf conveter, it works fine,
    there is a scart provider in this conveter and used that for audio or just
    straight rf out to tv tuner on uhf .
    rdg
    hi brother,thanx for ur reply,
    yes i understand that concept,but i am not wanting to convert to rf,,i need rca input into a video sender,not to an rf receiver.

  4. #4
    Junior Member Teacher
    Join Date
    Jun 2005
    Location
    Australia
    Posts
    415
    Posts Thanks / Likes

    Default

    Usually you have 4 channels on the video senders. Do they all have the same problem?

  5. #5
    Member Mentor
    Join Date
    May 2006
    Posts
    503
    Posts Thanks / Likes

    Default

    Quote Originally Posted by weirdo View Post
    Usually you have 4 channels on the video senders. Do they all have the same problem?
    hi m8,
    yes it does ,,but the problem is the sensitivity of its input circuit.i have the same problem with my silverbox through this system(still watchable ,but bright) but not as much as the dreambox,,it seems to have a more powerful output

  6. #6
    Silver Member Expert
    RDI - Board Default Avatar

    Join Date
    May 2006
    Location
    Chennai, India
    Posts
    2,090
    Posts Thanks / Likes

    Default

    Quote Originally Posted by davidss1 View Post
    hi m8,
    yes it does ,,but the problem is the sensitivity of its input circuit.i have the same problem with my silverbox through this system(still watchable ,but bright) but not as much as the dreambox,,it seems to have a more powerful output
    Try putting a resistor in the video cable which goes to the tv. I faced a similar problem but with another stb.

  7. #7
    Member Mentor
    Join Date
    May 2006
    Posts
    503
    Posts Thanks / Likes

    Default

    Quote Originally Posted by lnb15k View Post
    Try putting a resistor in the video cable which goes to the tv. I faced a similar problem but with another stb.
    hi m8,
    yes i thought maybe something simple like that,,can u advise a value of the resistor?is that in series on one wire only,or in parallel between the 2?
    thnx dave

  8. #8
    Silver Member Expert
    RDI - Board Default Avatar

    Join Date
    May 2006
    Location
    Chennai, India
    Posts
    2,090
    Posts Thanks / Likes

    Default

    I put a resistor which was lying on the bench as I was fed up to find a way to reduce the signal. I think it is some thing like 80ohms. Forgot it as I used it 3 years back. In series between the video output and the tv input. The contrast will be reduced and if the value is high you see the picture rolling on the screen. If it is then put a lower value.

  9. #9
    Member Mentor
    Join Date
    May 2006
    Posts
    503
    Posts Thanks / Likes

    Default

    Quote Originally Posted by lnb15k View Post
    I put a resistor which was lying on the bench as I was fed up to find a way to reduce the signal. I think it is some thing like 80ohms. Forgot it as I used it 3 years back. In series between the video output and the tv input. The contrast will be reduced and if the value is high you see the picture rolling on the screen. If it is then put a lower value.
    cheers m8,,,sounds like a simple and effective solution,,ill start digging in my "bits" box,,,hmm,,maybe a variable pot to "dial it in"
    thnx,,,,dave

  10. #10
    Silver Member Expert
    RDI - Board Default Avatar

    Join Date
    May 2006
    Location
    Chennai, India
    Posts
    2,090
    Posts Thanks / Likes

    Default

    Best of luck.

  11. #11
    canine consultant Expert
    Join Date
    Feb 2004
    Location
    over the Hill, and down the road
    Posts
    1,318
    Posts Thanks / Likes

    Default

    So turn the brightness and contrast down on the TV set, Dur.
    regards from OZ bassett

  12. #12
    Member Mentor
    Join Date
    May 2006
    Posts
    503
    Posts Thanks / Likes

    Default

    Quote Originally Posted by bassett View Post
    So turn the brightness and contrast down on the TV set, Dur.
    hi m8,
    the problem isnt so easily fixed,,the feed,,if put directly into a tv is fine,no problem,,,the problem is it is too hot a signal for my video sender unit (as i posted in the original post!)that i use to distro around my house.
    if u had read the replies in this thread,u would have been in no doubt about what i am trying to do,,,,,what are u trying to achieve with an unprovoked lame ass reply like that bassett?
    cheers,,,dave

  13. #13
    Junior Member Teacher
    RDI - Board Default Avatar

    Join Date
    Apr 2004
    Posts
    109
    Posts Thanks / Likes

    Default

    Quote Originally Posted by davidss1 View Post
    sorry if this isnt appropriate for this forum,,,but i am hopeing a member can help,,,
    my dreambox is connected via the rca outputs to a "video sender unit".the problem is that the signal is way too strong after it is transmitted,causing contrast and brightness problems.
    there are no variable resistors (trim pots) in the transmitter or receiver that i can use to attenuate the signal.
    does any member know of a simple way to MAKE an inline attenuator
    or a link to an appropriate forum would also be appreciated,,,thnx,,,dave
    Try loading the video line with a pot of say 10k. That is, put the far end pins of the pot across the + and - of the video from the dreambox. Now take out the video to the sender unit from the centre pin of the pot and the - line. Adjust the pot and you should be able to decrease the level of the video. Typically, line out video should be 1v peak to peak.

    I haven't tried this myself, but I think it will work. I am not sure about the best value for the pot, so if it is not suitable, try a different value.
    Don't Stop......Keep Learning!

  14. #14
    Member Mentor
    Join Date
    May 2006
    Posts
    503
    Posts Thanks / Likes

    Default

    Quote Originally Posted by cruiser View Post
    Try loading the video line with a pot of say 10k. That is, put the far end pins of the pot across the + and - of the video from the dreambox. Now take out the video to the sender unit from the centre pin of the pot and the - line. Adjust the pot and you should be able to decrease the level of the video. Typically, line out video should be 1v peak to peak.

    I haven't tried this myself, but I think it will work. I am not sure about the best value for the pot, so if it is not suitable, try a different value.
    hi m8,,thanks for the reply,,,i will try that,,,i did have limited sucsess with putting a 1k pot in series on + only,,reduction of brightness,,but it didnt correct the contrast at all,,,then i bridged a 50 ohm resistor from the output of the + to the -,,(just playing around) and got a massive reduction in brightness and some contrast reduction,,,but i think if it is wired the way u say it will have better results with the variability.,,do u think the 1k pot is too small?

  15. #15
    Junior Member Teacher
    RDI - Board Default Avatar

    Join Date
    Apr 2004
    Posts
    109
    Posts Thanks / Likes

    Default


    Quote Originally Posted by davidss1 View Post
    hi m8,,thanks for the reply,,,i will try that,,,i did have limited sucsess with putting a 1k pot in series on + only,,reduction of brightness,,but it didnt correct the contrast at all,,,then i bridged a 50 ohm resistor from the output of the + to the -,,(just playing around) and got a massive reduction in brightness and some contrast reduction,,,but i think if it is wired the way u say it will have better results with the variability.,,do u think the 1k pot is too small?
    I was first thinking of 1k too, but thought it might load the video line too much. It might be ok and the best way to know is to try it since you already have one.
    Don't Stop......Keep Learning!

 

 

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Back to Top