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Can't find this symbol

Discussion in 'General Electronics Discussion' started by Hsnopi, Jun 20, 2016.

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  1. Hsnopi

    Hsnopi

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    Dec 9, 2015
    hello all,
    noob question. i have this diagram i'm trying to understand. see image below. if you look on the right side near the po u-182, just to the left of the dotted line is a kind of dashed circle. it does something between connector D and connector A. It's not a join that i can tell because there are other locations that have the small dot as a symbol of that.
    Any idea what it means?
    Thanks
    [​IMG]
     
    KeithM likes this.
  2. donkey

    donkey

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    Feb 26, 2011
    ok having found a source of what this is for you are referring to a headset used in the army around 1966....
    I am assuming the that wire with the circle around it is a shielded wire similiar to antenna wire. he outer shielding helps negate RF interference.... I could be very wrong but it kinda makes sense
     
    davenn likes this.
  3. donkey

    donkey

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    Feb 26, 2011
  4. Externet

    Externet

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    Aug 24, 2009
    Means the red cable is a coaxial and its shield/jacket/braid is connected to pin -> A and to J1/P5
     
  5. 73's de Edd

    73's de Edd

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    Aug 21, 2015

    Sir Hsnopi . . . . . . .


    Being a Mega-ditto of Sir Externet.

    Look at the top left mike element and its matching transformer T3 it then makes a very short run and then connects into P5/J1.
    After that, the "hot /sensitive " RED wire is being within a shielded cable, as designated by your "mystery symbol / shielded wire run"
    Then the push to talk action of the IC / Rad switch then ascertains if the Interphone / intercom or the Radio xmitter receives the mike signal.
    If mike signal should be routed thru the outgoing RED wire again, it is still shielded until it reaches D pin of P2 connector.

    This precautionary shielding precludes any hum pickup by the wires routing, any RF pick up from the transmitter or any ground loops in the wiring run.

    73's de Edd
     
    Last edited: Jun 20, 2016
  6. Hsnopi

    Hsnopi

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    Dec 9, 2015
    Thank you for all the replies! I will now try to understand before asking yet more noob question:)
     
  7. Hsnopi

    Hsnopi

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    Dec 9, 2015
    ok, your replies helped immensely and that pdf is great! (love the typeface). What I'm endeavoring to do is hardwire the p3-p4 connector. It is a bulky rubber bit and has poor connectivity because it is infrequently used. The shape of the rubber doesn't help as it sometimes pushes just of the connector apart to make it unusable.

    2 questions
    would it help if each wire was shielded?
    does the shielding actually carry a signal or is it entirely for shielding/grounding purposes?
     
  8. Hsnopi

    Hsnopi

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    6
    Dec 9, 2015
    ok 3 questions
    Looking at the p3-p4 connector, the WHT on the P3 side seems to just end. Ideas? I'm about to take one of these apart, I think.
     
  9. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    Sir Hsnopi . . . . .

    Not necessary for every cable being shielded,
    as you can see, they only deemed that audio line to be shielded.

    That shield line,and it's continuity is carried forward until some physical change requires a short carryover
    and then it starts again JUST after passing that hindrance.

    It ends up as a complete, intact ground at the right A.

    #3 . . . . With none to go . . . .

    The VERY top circuitry loop is being a stand alone self powered two way phone . . . .No batteries are used ! . .you just have to string a WD1tt WIRE PAIR BETWEEN them however far they are separated.(limited)
    There is the normal switched access that you see that get field communications amplified into o the radio loop.
    OR you can listen in via a connection being made between the P3/4 top white and black pair, and you see the
    WHITE being carried over to the right.
    I would have to see the interconnect of that line to see how it related to that signal past that point.
    It was commonly used with a "Prick" 68 walkie talkie to tie a couple of mobile field phones into radio communications.
    With that . . .W3 . . . line coming in from field phone communications of belly crawling "grunts".
    With their observing forward "activity", sending corrections for artillery fire or calling in air support and correcting them.


    Thasssssssit . . . .

    73's de Edd
     
    Last edited by a moderator: Jul 3, 2016
  10. Hsnopi

    Hsnopi

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    Dec 9, 2015
    thanks all,
    lastly,
    is there any way you can tell what gauge the wire is from this diagram?
     
  11. davenn

    davenn Moderator

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    Sep 5, 2009
    nope
     
  12. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    I will say that if this was plugged into a Prick 68 That the wiring interfacing would be into stranded 20-22 AWG sized wiring.
    Fully relying upon my 50 year memory.
    The miniscule power being involved was the grounding of " C " wires connection to a relay coils winding within the transmit function.


    73's de Edd
     
    Last edited by a moderator: Jul 3, 2016
  13. Hsnopi

    Hsnopi

    43
    6
    Dec 9, 2015
    fantastic, thanks! so i need 5 or 6 wire bundle to replace this? If I got shielded wire would I need to wraap it like it is in the diagram?
     
  14. 73's de Edd

    73's de Edd

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    Aug 21, 2015
    Sir Hsnopi . . . . . . . . . . . .

    If your "reconstruction" does not incorporate using connector set P4-P3 the only shielded wire run there is, is being the P5 connector run over to P2 connectors pins A and D.

    All of the other wires require no shielding and the W1 thru W5 assigned designations are merely signifying separate insulated wraps that convert loose wiring into neat, tightly wrapped wiring bundles.


    73's de Edd
     
    Last edited by a moderator: Jul 27, 2016
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