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Ethernet between two houses

Discussion in 'Electrics UK' started by gbrown100, 15 Sep 2020.

  1. bernardgreen

    bernardgreen

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    Winston. Please give details of how you would trickle charge a battery from a DC power supply which does not have any means to set the charging current. Unregulated charging could destroy the battery.

    Supplying the router from a battery that is float charged from a battery charger set up to match the battery and load is a good idea.
     
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  3. Harry Bloomfield

    Harry Bloomfield

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    I provided a relative with access, using a pair of old wifi routers, each with a home-made Yagi antenna replacing the built in antenna. It worked well over an 1/2 mile link, despite numerous house with wifi in between - though still LoS over the top.
     
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  4. Harry Bloomfield

    Harry Bloomfield

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    Not unusual in a building which has 3Ph supply, to have various PC's on different phases and all interconnected by a wired LAN system.
     
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  5. SUNRAY

    SUNRAY

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    Also not unusual in larger buildings to be on different substations.
     
  6. JohnW2

    JohnW2

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    Indeed not unusual - it's even true in my house.

    Kind Regards, John
     
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  7. bernardgreen

    bernardgreen

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    True and therefore the wired LAN system will ( should ) be designed using equipment which will ( should ) be tolerant of the potential differences that will occur between the various PCs and nodes of the LAN
     
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  8. SUNRAY

    SUNRAY

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    From memory of stripping dead ethernet switches the transformers were rated at something like 1.5 to 2KV
     
  9. bernardgreen

    bernardgreen

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    True they resist being damaged by potential differences between the equipment but data quality can be affected.

    When data is affected it isn't always obvious to the user as error checking / error correction / repeated packets can restore the data.
     
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  11. Harry Bloomfield

    Harry Bloomfield

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    All such LAN interfaces include voltage isolation between socket and the rest of the card/interface, it is part of the spec. and it doesn't impact throughput. LAN cabling uses twisted pairs, so that when interference positively affects one of the cores of the pair, it will negatively impact the opposite core and thus cancel out. LAN cables are speced to be able to transmit and receive over 100m without any issues of data loss, if properly installed.
     
  12. bernardgreen

    bernardgreen

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    If the windings of the transformer are not 100% symmetrical to the core and each other then transients in the end to end potential can create a false signal.

    Bifilar and trifilar windings can be used to achieve the necessary symmetry but this construction can compromise the breakdown voltage as it relies totally on the enamel of the winding wire.
     
  13. JohnW2

    JohnW2

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    It seems to me that some barrels are being scraped pretty vigorously!

    Kind Regards, John
     
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  14. SUNRAY

    SUNRAY

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    Unless it's changed in the last 30 years the enamel is only rated at 50v, in order to increase the rating an additional barrier or gap is added between turns.

    To achieve KV's of isolation the windings will usually be on separate bobbins or sections.

    I have known ethernet to be operating at high PD's between between equipment do to an incorrectly earthed generator and seeing no apparent errors.
     
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  15. JohnW2

    JohnW2

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    Indeed, but one would need some awfully massive 'surges/spikes to get anything like 50V between adjacent turns of the same winding.
    Again indeed. Even when primary and secondary are on the same bobbin, there is usually at least some oiled paper, plastic tape or somesuch between the windings.

    As I said, albeit all sorts of things are theoretically possible (aka "not impossible"), I do think that "barrels are being scraped" :)

    Kind Regards, John
     
  16. SUNRAY

    SUNRAY

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    I wasn't thinking of adjacent turns, rather a block of 50V worth of turns, ie a 230V winding will consist of 5 layers of turns with a barrier between them.
    I'm not sure where the barrel scraping comes in, it would not occur to me to introduce any additional isolation between systems or buildings but the untimate is of course a fibre optic.
     
  17. bernardgreen

    bernardgreen

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    To get a good symmetry the wires for the two ( or three ) windings is twisted before being wound onto the core. Hence the isolation depemd on the enamel on the wire.

    [​IMG]
     
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