User Tag List

Page 2 of 3 FirstFirst 1 2 3 LastLast
Results 11 to 20 of 23

Thread: POE for a camera

  1. #11
    Join Date
    Jul 2006
    Location
    Roughly 5346 miles from Earls Court
    Posts
    2,865
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Gary11734 View Post
    Take a 500' box of Cat 6, Hook up the camera and power and see if it works. Leave the wire in the box. Also, you can see what the VD drop is. If it works, it works. The worst case scenario is it will probably work but have some dropped frames. You may not notice.
    (Don't bet on that.)
    However it probably won't, and it surely won't pass any certification test, which most customers insist on.

    Quote Originally Posted by Gary11734 View Post
    The 100m is for data to make the spec of the cable... I'm not sure, but the video may be running under UDP, not TCP which it doesn't matter if some frames are dropped. It will keep pushing out the signal no matter how the screen looks since the Ack/Nak is different... I think I explained this to be clear as mud.
    Doesn't matter about TCP/UDP/or whatever layer 3 protocol; it's a layer 0 and 1 problem. They may cause problems at layers 2 and above.


    So, sure, try that as an academic exercise, but it would very bad practice to install TP ethernet over 100m (330').

  2. #12
    Join Date
    Dec 2005
    Location
    Florida
    Posts
    421
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by zbang View Post
    (Don't bet on that.)
    However it probably won't, and it surely won't pass any certification test, which most customers insist on.



    Doesn't matter about TCP/UDP/or whatever layer 3 protocol; it's a layer 0 and 1 problem. They may cause problems at layers 2 and above.


    So, sure, try that as an academic exercise, but it would very bad practice to install TP ethernet over 100m (330').
    Exactly what I said. All academic. Maybe I'll put one through the test. I have a bunch of Panasonic IP's on the self. I still would like to know what the VD is in the real world scenario. As far as 0 and 1's, I wonder if it knows when it goes over 100 meters, lets say to 101? The certification is based on the speed of which the cable is saying it will perform at. I can't remember what certification number it is. Being a ham and tearing everything up in the garage from engines to building Heathkits, and now Arduino projects have their downsides in my inability to not tinker with the stuff.

  3. #13
    Join Date
    Jul 2006
    Location
    Roughly 5346 miles from Earls Court
    Posts
    2,865
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Gary11734 View Post
    As far as 0 and 1's, I wonder if it knows when it goes over 100 meters, lets say to 101? The certification is based on the speed of which the cable is saying it will perform at.
    It doesn't of course know exactly. Some transceiver/cable pairings will reliably work past that, but it's still out of spec.

    As a ham, think about this as an 125MHz* balanced analog transmission line, not as 1's and 0's. You have not only the DC resistance of the line, but the distributed reactance and pair-to-pair cross-talk. There's also the slight difference in length of each pair due to the different twist ratios; the PHY at each end is supposed to deal with that. For some light reading, or a headache , look at the Ethernet physical spec... there's a lot of wizardry involved; it's rather interesting if you're into the low-level workings.

    *not actually correct, IIRC the rate is 125M baud (symbols/second, not bits/second)

    Kind of amazing that it works at all .

  4. #14
    Join Date
    Dec 2005
    Location
    Florida
    Posts
    421
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by zbang View Post
    It doesn't of course know exactly. Some transceiver/cable pairings will reliably work past that, but it's still out of spec.

    As a ham, think about this as an 125MHz* balanced analog transmission line, not as 1's and 0's. You have not only the DC resistance of the line, but the distributed reactance and pair-to-pair cross-talk. There's also the slight difference in length of each pair due to the different twist ratios; the PHY at each end is supposed to deal with that. For some light reading, or a headache , look at the Ethernet physical spec... there's a lot of wizardry involved; it's rather interesting if you're into the low-level workings.

    *not actually correct, IIRC the rate is 125M baud (symbols/second, not bits/second)

    Kind of amazing that it works at all .
    The spec will get people where they can't see the forest for the trees. I live inside the box when in business given that I have to meet spec. But, I'm always thinking outside the box when it comes to why things work in the first place.

    The key is, would it work if I pull a 500' of Cat5E off the self and fire it up with the wire still in the box? I say, yes! If not, well no loss here.

    Ah yes, the seven layers... I passed the Microsoft IT Pro course years ago. I figured the data cabling wasn't the big deal. Now those guys that can make 100 cables look good in a tray is impressive. Punch down is BORING! Getting in front of the owner where you do the backbone supplying the switches and the routing tables was a better way to go. I started working on my RCDD a few years back but I just get bored when it comes to data.

  5. #15
    Join Date
    Apr 2018
    Location
    AƱasco, Puerto Rico
    Posts
    79
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Have you considered the option of going WiFi on this? With a good transmitter and receiver, and possibly some narrow focus parabolic antennas on each end it might work. POE does have a distance limit and as you get there, speed drops and reliability of connection becomes more of an issue.

  6. #16
    Join Date
    Jun 2014
    Location
    Madison, WI, USA
    Posts
    361
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by caribconsult View Post
    Have you considered the option of going WiFi on this? With a good transmitter and receiver, and possibly some narrow focus parabolic antennas on each end it might work. POE does have a distance limit and as you get there, speed drops and reliability of connection becomes more of an issue.
    Beat me to it. I was just going to recommend a directional WiFi link. They make small outdoor directional antennas for pretty cheap. Check out Amazon and Ubiquiti Networks' stuff. Of course, you'll need power out there unless you do a solar/battery DC system.
    Tell me and I forget. Teach me and I remember. Involve me and I learn.

  7. #17
    Join Date
    May 2018
    Location
    Jamaica and london
    Posts
    1,306
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    camera uses dc, transmitter probably uses dc.. amplifier would use dc as well... tigh pattern UHF using can system for transmit/receive... the higher the better to cut down on distance and interception likelihoods... hmmm... as a ham operator I am intriqued by the idea but not sure what frequencies could legally be used for an unlicensed security link... of course, if you are not worried about interception of signals then commercial gear is available... but looks like a linking system for repeaters would work here...two of those micro computers, one at the area you want the cameras, for controlling them... one at the security site for decoding and saving the actual signals... you would be able to actually put several cameras at the remote area that way, if needed...

    Of course, a dedicated wireless router on a directional wifi antenna could do the same... Shame I am no longer in Virginia or would go up on the tomato net and find the guys who already been there done that as a fun experiment..lol...
    Student of electrical codes. Please Take others advice first.

  8. #18
    Join Date
    Apr 2019
    Location
    07728
    Posts
    1
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by texie View Post
    The POE question is moot as you can't have an ethernet link beyond 333 feet anyway.
    IEEE says 328'

    Sent from my SM-G973U using Tapatalk

  9. #19
    Join Date
    Apr 2019
    Location
    Myrtle Beach, SC
    Posts
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

  10. #20
    Join Date
    Dec 2018
    Location
    Boston
    Posts
    8
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    which one is best in low budget?

Posting Permissions

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