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Extending CAT5 cable

Discussion in 'Electronic Repair' started by klem kedidelhopper, Jan 8, 2013.

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  1. We need to run video over some existing CAT5 cables using baluns on
    either end. The existing cables are all terminated with jacks on both
    ends. One end is a patch panel and on the other end they are connected
    to jacks which are mounted on the baseboards. We plan to make 8 foot
    cables with an RJ 45 on one end, plug it into the baseboard jack, run
    the cable up the wall and then connect the other end to the balun and
    then to the camera. Would it matter if this short piece of cable were
    CAT3? Thanks, Lenny
     
  2. Given that CAT3 is spec'd only to 16MHz, * and CAT5 is spec'd to 100Mhz, you
    might run into problems with wideband signals.

    As this cabling isn't horribly expensive, why not use CAT5?

    * I'm obliged to anticipate the obvious objection -- "But that doesn't mean it
    won't work at 100MHz." True. But it isn't spec'd at that frequency, so you
    have no guarantee how it will perform.
     
  3. gregz

    gregz Guest

    I see it working best if your only using one pair.

    Greg
     
  4. why would you use cat3? Also where do you even get cat3 unless you're a
    copper thief these days?

    I'd use silver satin, or some 1980s 50 foot coiled kitche telephone cords,
    with a handset swivel thingy on it, with nothing but the finest and most
    reasonably priced rj11 to rj45 adapters from Black Box.
     
  5. Well the obvious reason to use CAT 3 is because as a former telephone
    systems contractor I happen to have a shit load of it and I didn't
    want to have to buy any additional CAT 5 at this time. Was that so
    difficult to figure out? Most people that visit this group are not
    thieves, nor are they idiots. So don't act like one. You have no
    audience. We ask questions because we're looking for some advice from
    someone more knowledgeable than ourselves. And personally I really
    appreciate it when I get assistance with a problem. So if you really
    need to be a smart ass, please don't bother responding to my posts.
    Lenny
     
  6. I just thought of something else. If CAT3 is spec'd out to 16MHZ and a
    typical NTSC TV channel was 6MHZ wide with 250KHZ guard bands on
    either end why would CAT3 cause any problems in a video application?
    It seems to exceed the requirements for TV video. Lenny
     
  7. gregz

    gregz Guest

    Regardless of the cable, it will have high frequency loss. It should work
    fine, unless you start to see two of everything. Shadows ?

    Greg
     
  8. Guest

    The main problem is driving and terminating the CAT cable at the
    correct impedance. Improperly terminated cable for video make for some
    poor video but it depends on your needs/demands. What I think is bad
    may be more than sufficient for you - or not.

     
  9. I do understand what you're saying about impedance mismatches and I
    can also see where marrying this cable with some (probably) Chinese
    baluns which are "supposed" to be constructed correctly could upset
    impedances, but Base band video was what I was referring to. So in
    that sense the response demands of the cable and the baluns would be
    limited to 4 or at best 5MHZ right, and then in theory wouldn't even
    CAT 3 be overkill?
    Lenny
     
  10. I do understand what you're saying about impedance mismatches and I
    can also see where marrying this cable with some (probably) Chinese
    baluns which are "supposed" to be constructed correctly could upset
    impedances, but baseband video was what I was referring to. So in
    that sense the response demands of the cable and the baluns would be
    limited to 4 or at best 5MHz (right?), and then in theory wouldn't even
    CAT3 be overkill?

    Probably. But CAT5 or CAT5e aren't horribly expensive, nor do you need a lot.
    I understand you don't want to waste materials you already have, but why not
    just buy the matching type, and that will be one less thing to worry about?
     
  11. well hell, use some double cotton covered wire then.
    It was foolish for me to to assume most people have bought cable in the
    past 20 years.
     
  12. The cable I have comes from various sources. No big name brands so
    figuring exact losses would be difficult however the Belden specs are
    eye openers. Thanks Michael for posting those. Lenny
     
  13. I can't blame anyone for not wanting to spend money if they don't have to.
    (I'm no different.) But isn't it time to "knuckle down, buckle down, do it, do
    it, do it"?
     
  14. Guest

    Sometimes there are so many variables that the only thing to do is TRY
    IT!!! There is no obvious reason it won't work, but there is also no
    way to guarantee it WILL work.

    Understanding theory is all well and good. Applying it properly is
    another thing. In the final test, the emperical results are what
    counts.

    One story goes that Thomas Edison assigned a simple task to a newly
    hired engineer - calculate the volume of a light bulb. The newbie
    measured the bulb at the points he felt were critical and spent the
    afternoon calculating the volume. Edison looked at the numbers and
    said "You're off by at least 10%". Edison then took the light bulb,
    drilled a little hole in it, filled it with water, then drained the
    water into a graduated cylinder. And showed the engineer his numbers
    were off by 10%.

    PlainBill
     
  15. tuinkabouter

    tuinkabouter Guest

    But Edison measured the inside volume. The engineer calculated the
    outside volume. To proof this, the engineer submerges the light bulb
    and measured the water rise.
    To prove his measurement he measured the force to keep it submerged.

    So he proved that Edison was wrong.
    The glass of the bulbs in those times was very thick.
     
  16. One story goes that Thomas Edison assigned a simple task to a newly
    But Edison measured the inside volume. The engineer calculated the
    outside volume. To proof this, the engineer submerges the light bulb
    and measured the water rise.
    To prove his measurement he measured the force to keep it submerged.

    So he proved that Edison was wrong.
    The glass of the bulbs in those times was very thick.


    You're missing the point of the story. There are ways to measure things that
    are quick and elegant -- rather than applying a brute-force approach.
     
  17. The hole in the bulb was pretty slick. So was the water for that
    matter. I picked up a couple of baluns today and I am TRYING it
    tomorrow, CAT3, CAT 5, Coax, etc. and I'll let you guys know. Thanks
    for everyone's input. I really do appreciate it. Lenny
     
  18. tuinkabouter

    tuinkabouter Guest

    No. Edison asked the engineer: "calculate the volume of a light bulb".
    He did not ask to measure it.

    Edition should have asked: "what is the inside volume of this light
    bulb". Then the engineer could decide to use other physical means to get
    the right answer.

    Don't mess with engineers.
     
  19. You're missing the point of the story. There are ways to measure things
    So why did Edison make the guy look like a fool?
     
  20. Leif Neland

    Leif Neland Guest

    William Sommerwerck frembragte:
    That's the perogative of the boss/mentor/idol, to make the little guy
    look like a fool even if he is right.

    Leif
     
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