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Please help to buy those components

Discussion in 'General Electronics Discussion' started by michael1978, Dec 11, 2017.

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  1. michael1978

    michael1978

    388
    2
    Mar 17, 2012
    please can somebody help, how to find in electronics shop online
    those components and to buy, is here juse one to make for all, i need juse one, wich i can use for all projetcs
    L1 antenna coil: 470uH with 1 turn wrapped = 2
    L2 antenna coil: 470uH primary, 23uH secondary = 2
    L3 antenna coil: 600uH to 680uH primary, to to 20 turn secondary = 2
    L4 antenna coil: 330uH primary 10 to 20 turns for secondary = 2
    L5 antenna coil: 600uH to 680uH with tap or secondary winding = 2

    i dont know how to find self and to buy, can somebody teach me how to select

    because i am reading on book, make your own radio transistor
    i was in one shop here, i whait 3 months he cant find me, because he say is very difficult to find and, they dont use anymore, but book is from 2013 is not old thnx
     
  2. BobK

    BobK

    7,682
    1,688
    Jan 5, 2010
    These are not off-the-shelf components. Does not the book not tell you how to make them yourself?

    Bob
     
  3. kellys_eye

    kellys_eye

    4,275
    1,147
    Jun 25, 2010
    Does the book not advise on how to MAKE those coils? They do sound like INSTRUCTIONS rather than a list of bits to be purchased.
     
  4. michael1978

    michael1978

    388
    2
    Mar 17, 2012
    no i read th book, can you help how to make please
     
  5. kellys_eye

    kellys_eye

    4,275
    1,147
    Jun 25, 2010
    All I can recommend is that you obtain some ferrite/dust iron toroids and wind coils to those values yourself. The Micrometals range are popular and fairly easy to obtain.

    There are various sites that offer help in doing this - tools for calculating the required number of turns etc, such as this:

    http://www.micrometals.com/downloads/Toroid.zip
     
  6. 73's de Edd

    73's de Edd

    3,138
    1,320
    Aug 21, 2015
    Can you copy relevant pages from the book, so that we can evaluate its content here ?
    Or the name of the book and its author, as we might also find it .
    73's de Edd
     
  7. michael1978

    michael1978

    388
    2
    Mar 17, 2012
    here the name of book Build Your Own Transistor Radios 2013
    you can find it on the internet
     
  8. kellys_eye

    kellys_eye

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    Jun 25, 2010
    Can you scan a copy of the pages you're referring to into here?

    I don't think we're about to purchase a book just to help you resolve some construction issues but if you posted the pages we could tell you how to proceed.

    I don't know of ANY construction book of that level that simply states the inductance of the coils required without giving some indication of either how to make them or where to purchase them.
     
  9. michael1978

    michael1978

    388
    2
    Mar 17, 2012
    ah ok no problem
    for example this Naamloos.jpg
     
  10. kellys_eye

    kellys_eye

    4,275
    1,147
    Jun 25, 2010
    Those inductors symbols are typical of the way they indicate the toroidal construction types.

    You can get tables of the various toroids and their parameters where the tables show how many turns of wire are needed to get a specific inductance.

    In your schematic, L1 is shown with two dots...... these indicate the START of the winding on the toroid core and that there are two such windings on the same core material.

    L2 and L3 are standard 'chokes' and available as axial devices from many component suppliers (they look like small fat resistors).

    In this example you would wind magnet wire around an appropriate core to get the 470μH value THEN wind another SINGLE turn around the same core. You then have the coil labelled as L1 in your schematic but you MUST take care to note the START point of your winding so they can be connected in the right phase.

    Here's a document that will help - it's 'Toroids for the terrified' and tells you how to chose and use the right one.
     

    Attached Files:

  11. BobK

    BobK

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    Jan 5, 2010
    In that schematic, the two coils on the left are almost certainly to be wound on a ferrite rod and make up the antenna for the radio. If the book does not tell you how to wind them, then it is useless. I don't believe they can be wound on a toroid because that would not make an effective antenna.

    Edited to add: The other two inductors are standard parts that you can buy.

    Bob
     
    Last edited: Dec 12, 2017
    kellys_eye likes this.
  12. michael1978

    michael1978

    388
    2
    Mar 17, 2012
    no they use for antenna this sort
    look
    Naamloos.jpg

    i dont know how to make
     
  13. BobK

    BobK

    7,682
    1,688
    Jan 5, 2010
    So, now are you telling us the book DOES tell you how to construct the antenna coils?

    And, by the way, that is what I meant by a ferrite rod.

    Bob
     
  14. BobK

    BobK

    7,682
    1,688
    Jan 5, 2010
    Is not a radio circuit?

    I build a TRF radio using MK484 which is pretty much the same thing but 3 stages all in a TO92 package to tune the local station that broadcasts the Red Sox games. It can separate the signal from a very strong station nearby, though I have to turn the antenna to null the strong station.

    Bob
     
  15. michael1978

    michael1978

    388
    2
    Mar 17, 2012
    No he just show this kind of antenna, but for more details NO, so please can you help me to make own. what i need?
     
  16. michael1978

    michael1978

    388
    2
    Mar 17, 2012
    this book teach you step by step up to fm tuner, but the problem was antenna, i told al ready i whait 3 months for those antenna, in the end he say i cant help you.
     
  17. michael1978

    michael1978

    388
    2
    Mar 17, 2012
    iam not agree, i dont know how to make tht antenna, because this book is 2013, and the author with not speak about old time, but he want to teach you......why you ont help how to make an antenna and you speak something else
     
  18. michael1978

    michael1978

    388
    2
    Mar 17, 2012
    i have but i dont know how to make antenna rf, i have a wire + the other stuck where you wind wire
     
  19. duke37

    duke37

    5,364
    772
    Jan 9, 2011
    Ferrite rods are available from many hobby stores but cost a considerable amount. Get a long one for maximum sensitivity. As has been suggested, get one from a scrap AM radio which will have the coil already fitted.

    To wind your own coil, you ideally should use Litz wire with cotton (or other) insulation. To do the winding, place the rod in a hand driven drill and carefully wind the turns side by side. Count the turns, it is easy to do it when winding but much more difficult to count when they are in place.

    A coil of a few turns one end connected to earth and the other end connected to a long wire will give more sensitivity. This winding is often available on old portable radios intended for use in a car.
     
  20. michael1978

    michael1978

    388
    2
    Mar 17, 2012
    thank you, ,
    but those antenna have 4 wire to connect, do you see, how can i make one like here Naamloos.jpg
     
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