Best way to replace DSL with point-point wirless? - Networking

This is a discussion on Best way to replace DSL with point-point wirless? - Networking ; david writes: >On Tue, 08 Jul 2008 07:36:32 +0000, Unruh rearranged some electrons to >say: >> Also since the >> supply is two phase, this would mean there would have to be two wires >> strung -- that's a lot ...

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Thread: Best way to replace DSL with point-point wirless?

  1. Re: Best way to replace DSL with point-point wirless?

    david writes:

    >On Tue, 08 Jul 2008 07:36:32 +0000, Unruh rearranged some electrons to
    >say:


    >> Also since the
    >> supply is two phase, this would mean there would have to be two wires
    >> strung -- that's a lot of copper.
    >>


    >Many newer primary condutors in the US are ACSR (alumimum conductor-steel
    >reinforced). Most secondary drops to residences are also aluminum
    >conductors. Not as good as copper, but much lighter and cheaper.


    Well, with a steel core, I am not sure of the lighter, but cheaper is
    probably right, although they probablyhave to be a larger gauge, esp since
    both Al and esp Fe are worse conductors than copper> Ie it would not
    surprize me if they were actually heavier than copper.


  2. Re: Best way to replace DSL with point-point wirless?

    On 08 Jul 2008, in the Usenet newsgroup comp.os.linux.networking, in article
    <487314e4$0$2525$da0feed9@news.zen.co.uk>, Klunk wrote:

    >That's a heck of a lot of transformers to fit and I've got to wonder
    >what the thinking behind doing it that way is.


    Probably efficiency, and the fact that houses here are not that dense,
    but tend to use a lot of current. I checked the spacing in my
    neighborhood last night - average was about 280 feet/85 meters.

    >Here the three phase supply comes in to a small 'sub station' which
    >takes the supply (typically 33kv,22kv or 11kv) and drops it to 240v
    >with three large trannys. These will normally feed several hundred
    >homes. We do get the stick type transformers as well, but they tend
    >to be feeding lots more homes.


    Street distribution to neighborhoods might be done at various voltages
    ranging from 2300, 4160 (both pretty rare now), 13200 or 33000 Volts
    phase-to-ground. Those lines are sourced at transformer sites every
    few miles, which are fed from 60-130KV lines. Those lines are fed by
    major substations where it's stepped down from 230 or 460KV. Trying to
    distribute to several hundred homes at the residential voltage would
    be horribly inefficient - the complex I live in mentions 3000 housing
    units in 1150 acres = 463 hectares (not really a fair measurement, as
    this includes two parks, four shopping areas, a school, and some
    unusable land needed for rain ponding/drainage). Ignoring the
    business/shopping stuff, most of those housing units are fused for
    37.5, or 50 KVA (150 or 200 Amps per leg).

    Look at some large wire - the largest my reference book lists is 4/0
    AWG (also called 0000) which is 0.460 inch (11.684 mm) in diameter
    without insulation. At 20C/68F, it has a resistance of 0.04901 ohms
    per thousand feet (for annealed copper, hard drawn would be slightly
    higher), and the wire alone weighs 640.5 pounds per thousand feet. Have
    you priced copper lately? Don't forget you need three such wires, but
    only need to compute loss based on two wires. Copper to expensive?
    You can use aluminum, or aluminum alloys, but the wires have to be
    physically larger to have the same resistance loss.

    Now, how far can you run this wire carrying 100 Amperes before you
    have a 2.5 percent wire loss? The answer is obviously "not very far".
    Fifty houses on the same wire? Somehow, I don't think it's practical.
    (Heck, _five_ houses on the same wire is going to be a problem.) So
    your option is either running (much) larger wires (or multiples of
    larger wires), or kicking the voltage up - but it's HIGHLY unlikely
    we're going to change the household voltage (think of the hoops you
    guys went through to "meet" the EU standard voltage), and that means
    the distribution voltage has to be higher and that's why the
    transformers are relatively close.

    >The 'baseboard' thing, by the way, came to me in a flash of light. It's
    >what we call 'skirting boards'. Typically telecoms and network cables
    >are clipped or stapled to these on the surface.


    That's the way it was done here before about 1950. But our home owners
    don't want to see those nasty old wires, so the preference is to hide
    them if at all possible - behind that molding/board if necessary.

    Old guy

  3. Re: Best way to replace DSL with point-point wirless?

    On Tue, 08 Jul 2008 14:36:34 -0500, Moe Trin rearranged some electrons to
    say:

    > On 08 Jul 2008, in the Usenet newsgroup comp.os.linux.networking, in
    > article <487314e4$0$2525$da0feed9@news.zen.co.uk>, Klunk wrote:
    >
    >>That's a heck of a lot of transformers to fit and I've got to wonder
    >>what the thinking behind doing it that way is.

    >
    > Probably efficiency, and the fact that houses here are not that dense,
    > but tend to use a lot of current. I checked the spacing in my
    > neighborhood last night - average was about 280 feet/85 meters.
    >
    >>Here the three phase supply comes in to a small 'sub station' which
    >>takes the supply (typically 33kv,22kv or 11kv) and drops it to 240v with
    >>three large trannys. These will normally feed several hundred homes. We
    >>do get the stick type transformers as well, but they tend to be feeding
    >>lots more homes.


    I think he meant the substation feeds several hundred homes. This I can
    believe. Feeding several hundred homes at the secondary distribution
    voltage wouldn't work, for the reasons you stated below.


    > Street distribution to neighborhoods might be done at various voltages
    > ranging from 2300, 4160 (both pretty rare now), 13200 or 33000 Volts


    7.2 kV is also very common.

    > phase-to-ground. Those lines are sourced at transformer sites every few
    > miles, which are fed from 60-130KV lines. Those lines are fed by major
    > substations where it's stepped down from 230 or 460KV. Trying to
    > distribute to several hundred homes at the residential voltage would be
    > horribly inefficient - the complex I live in mentions 3000 housing units
    > in 1150 acres = 463 hectares (not really a fair measurement, as this
    > includes two parks, four shopping areas, a school, and some unusable
    > land needed for rain ponding/drainage). Ignoring the business/shopping
    > stuff, most of those housing units are fused for 37.5, or 50 KVA (150 or
    > 200 Amps per leg).
    >
    > Look at some large wire - the largest my reference book lists is 4/0 AWG
    > (also called 0000) which is 0.460 inch (11.684 mm) in diameter without
    > insulation.


    4/0 is certainly not the largest wire available, but it starts to get
    pretty hard to handle when you're in large MCM (thousand circular mils)
    territory.

    At 20C/68F, it has a resistance of 0.04901 ohms per thousand
    > feet (for annealed copper, hard drawn would be slightly higher), and the
    > wire alone weighs 640.5 pounds per thousand feet. Have you priced copper
    > lately? Don't forget you need three such wires, but only need to compute
    > loss based on two wires. Copper to expensive? You can use aluminum, or
    > aluminum alloys, but the wires have to be physically larger to have the
    > same resistance loss.


    See ACSR



  4. Re: Best way to replace DSL with point-point wirless?

    ibuprofin@painkiller.example.tld (Moe Trin) wrote in
    news:slrng75p97.fr1.ibuprofin@compton.phx.az.us:

    [snip]
    > generally means a pole-pig on every 1 to 4 poles. For an underground
    > feed, the distances are similar, but the transformer is located on an
    > easement (someone owns the property, but the power company has
    > permanent permission to put something there) on the side of the
    > street, behind the sidewalk if one exists. In this house, the


    I'm a programmer for an Oklahoma power company and our construction is
    'back-lot' rather than 'front-lot' like what you're describing. So, same
    numbers of houses per distribution transformer, but we have lines of
    poles down the non-existent alley at the backs of the lots for overhead
    and for underground, wires buried in the same line with the pad-mount
    transformers usually in a back corner of someone's lot.

    Customers don't really want those ugly green pad-mounts in their front
    yards, you know? ;v)

    As for service size, my 1940-ish home has a 60Amp meter base and most
    newer construction uses 100Amp bases but larger homes do have 200Amp
    meters.

    --
    The email address, above, is most certainly munged. Perhaps you
    might reply to the newsgroup, instead? Thanks!

  5. Re: Best way to replace DSL with point-point wirless?

    On Thu, 10 Jul 2008, in the Usenet newsgroup comp.os.linux.networking, in
    article , james wrote:

    >ibuprofin@painkiller.example.tld (Moe Trin) wrote


    >> For an underground feed, the distances are similar, but the
    >> transformer is located on an easement (someone owns the property,
    >> but the power company has permanent permission to put something
    >> there) on the side of the street, behind the sidewalk if one exists.


    >I'm a programmer for an Oklahoma power company and our construction is
    >'back-lot' rather than 'front-lot' like what you're describing. So,
    >same numbers of houses per distribution transformer, but we have lines
    >of poles down the non-existent alley at the backs of the lots for
    >overhead and for underground, wires buried in the same line with the
    >pad-mount transformers usually in a back corner of someone's lot.


    The first house I owned was like that - and as long as there is wide
    enough access for work crews to get back to the pad or pole-line,
    it is sometimes considered a better alternative. If you still have
    people reading meters, it's a minor disadvantage as the meter is
    generally not accessible from the street.

    >Customers don't really want those ugly green pad-mounts in their
    >front yards, you know? ;v)


    Green??? I'm in Arizona, and the pad mounts are painted a light brown
    to blend in with the ground color. ;-)

    >As for service size, my 1940-ish home has a 60Amp meter base and most
    >newer construction uses 100Amp bases but larger homes do have 200Amp
    >meters.


    A nephew of mine was buying a house - small (2/1 ~900 SqFt) and we went
    with him to look it over. Knowing his (and the bride-to-be) lifestyles
    I strongly recommended he look at something else, as it had the same
    60Amp service, and either one or two outlets in every room except the
    kitchen which had three!!! Oh, and they were screw fuses rather than
    breakers.

    Old guy

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