Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 35

Thread: Underground Null Pixels

  1. #21
    Join Date
    Nov 2011
    Location
    Chicago - Southwest Suburbs
    Posts
    6,258
    Post Thanks / Like

    Default Re: Underground Null Pixels

    I don't think anyone here recommended running Ethernet. But it is important to run signals using proper signal wiring. A #10 loose conductor is not a good signal wire. And you're figuring out why. You generally won't see a signal wire larger than 20 gauge. And it will always be arranged with its balanced partner or ground wire in a way that controls the physical orientation of the two conductors. It may be parallel bonded like most pixel wire or it may be twisted like cat5 or audio wire, or it can be coaxial like video and radio cabling. But what's common in all of these cases is that the signal wires have a constant orientation over the length of the wire. This gives you a controlled and known impedance. You're not going to get that with loose conductors or large ones.
    Remember the old days of phone modems? That technology topped out at 56k bandwidth. This is due to the kind of wiring in place in the telephone network. Pixels run at 800k. Even that old phone wiring is much better suited to carry a data signal than what you're describing you've done.
    And lastly, yes the earth does interact with your signals. All underground data signal wiring should be either twisted pair or coax.
    The bottom line is that your choice of wire is causing your problem. #10 is fine for your power pair, but you should use a proper twisted pair wire for the data pair.


    Sent from my iPhone using Tapatalk

  2. #22
    Join Date
    Dec 2016
    Location
    Anchorage, AK
    Posts
    61
    Post Thanks / Like

    Default Re: Underground Null Pixels

    I agree with Jchuchla, I got distracted by all the posts on water. If you are using a single strand wire for data, then the moment you bury it underground, you have created a capacitor on your data line. Capacitance is created by 2 conductors, in your case: data wire and soil. Capacitance can short out certain frequencies depending on the value. I would switch to coax. It shields the data line. Try it on the short string and see if it fixes the problem. I am an Electronics Tech by trade, 30+ years. Hope this helps.
    Last edited by aknflyer; 04-14-2017 at 01:44 AM.

  3. #23
    Join Date
    Jun 2016
    Location
    Brookfield WI
    Posts
    8
    Post Thanks / Like

    Default Re: Underground Null Pixels

    Quote Originally Posted by jchuchla View Post
    I don't think anyone here recommended running Ethernet. But it is important to run signals using proper signal wiring. A #10 loose conductor is not a good signal wire. And you're figuring out why. You generally won't see a signal wire larger than 20 gauge. And it will always be arranged with its balanced partner or ground wire in a way that controls the physical orientation of the two conductors. It may be parallel bonded like most pixel wire or it may be twisted like cat5 or audio wire, or it can be coaxial like video and radio cabling. But what's common in all of these cases is that the signal wires have a constant orientation over the length of the wire. This gives you a controlled and known impedance. You're not going to get that with loose conductors or large ones.
    Remember the old days of phone modems? That technology topped out at 56k bandwidth. This is due to the kind of wiring in place in the telephone network. Pixels run at 800k. Even that old phone wiring is much better suited to carry a data signal than what you're describing you've done.
    And lastly, yes the earth does interact with your signals. All underground data signal wiring should be either twisted pair or coax.
    The bottom line is that your choice of wire is causing your problem. #10 is fine for your power pair, but you should use a proper twisted pair wire for the data pair.
    Ha I'm only 22, no idea what a phone modem is.

    In all seriousness thank you. I just figured that a bigger gauge wire would be better for data like it is for power. Didn't know that would be an issue for data transmission, but your explanation makes sense. I'll give coax a try tomorrow.

    Thank you,

    Ben

  4. #24
    Join Date
    Dec 2016
    Location
    Anchorage, AK
    Posts
    61
    Post Thanks / Like

    Default Re: Underground Null Pixels

    make sure you ground only one end of the coax, preferably the source side. Otherwise you could create ground loops.

  5. #25
    Join Date
    Jun 2016
    Location
    Brookfield WI
    Posts
    8
    Post Thanks / Like

    Default Re: Underground Null Pixels

    With coax, will I likely still need the null pixels in the same spots? Currently I have them spaced about 12 feet apart. I vaguely remember seeing somewhere that coax could extend the signal greatly between null pixels.

    With regards to grounding it, is it as simple as hooking up the ground to the shielding? I'm not very familiar with coax.

  6. #26
    Join Date
    Dec 2016
    Location
    Anchorage, AK
    Posts
    61
    Post Thanks / Like

    Default Re: Underground Null Pixels

    You could probably extend them a bit, hard to come up with a hard number without the design...As far as the connections: you can solder a 22awg or 24awg wire to the shield and attach it to a ground on your controller. Creates a path for stray signals or capacitance to be nullified. Best guess, with coax you might be able to add 10' reliably till the next null pixel.

  7. #27
    Join Date
    Dec 2008
    Location
    Ft. Mitchell, KY (Cincinnati Area)
    Posts
    3,904
    Post Thanks / Like

    Default Re: Underground Null Pixels

    Quote Originally Posted by bob81354 View Post
    I would use a 4 or 6" peace of 1/2" PVC with end caps and wire coming out of both ends with Silicone
    Never got to use my Pixel Show, but this is what I'm doing for Pixel Garden Lighting.

    Another technique I have used with other waterproof connections is to fill the heat shrink with silicone before shrinking.
    No display again in 2016
    Just too much going on to get things going the way I want. So continuing the hiatus
    www.ChristmasInKentucky.com[/SIZE][/FONT]

  8. #28
    Join Date
    Dec 2016
    Location
    Shelby Township MI
    Posts
    126
    Post Thanks / Like

    Default Re: Underground Null Pixels

    Anyone ever used clear epoxy resin to waterproof any of their permanent connections like this. Maybe uamps, null pixels,or anything?

  9. #29
    Join Date
    Jun 2016
    Location
    Brookfield WI
    Posts
    8
    Post Thanks / Like

    Default Re: Underground Null Pixels

    So I used coax for my small 6 foot underground section. It worked great for the first day, then the next day I had major signal problems starting right after the underground part. I did not ground the shielding, and that will be the first thing that I try tomorrow. Any ideas as to if that will make the difference? My next question is can I just ground to the pixels? Or should it be a dedicated line going back to the power supply? If grounding doesn't fix it I'm honestly not sure what my next move will be.

    Once again, I really appreciate everybody's help. You guys have a much better understanding of the electrical aspects and I enjoy learning about it.

  10. #30
    Join Date
    Jun 2011
    Posts
    1,559
    Post Thanks / Like

    Default Re: Underground Null Pixels

    Differential and waterproof data cable.

Page 3 of 4 FirstFirst 1234 LastLast

Bookmarks

Posting Permissions

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