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Some More Simple FM Transmitters

Discussion in 'Electronic Projects' started by Iceman_Chris, Nov 28, 2004.

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  1. tytower

    tytower Banned

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    What I meant by bandwidth is the precision of the tuneable range ie 108Mhz to say 110 Mhz. for fine wire as opposed to sau 106Mhz to 113Mhz for thicker wire . See what I am asking?

    I take it you are probably not a radio ham?
    Wire cross -section is quite a factor at HF. The cross section of the driven element can change the sharpness of bandwidth of a beam antenna by as much as 30%.
     
  2. audioguru

    audioguru Well-Known Member Most Helpful Member

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    I know that very high frequency RF travels on the surface of a conductor and if it is thicker then it has a larger surface and therefore its RF resistance is less.
    You mention "driven element" and "beam antenna". We were talking about just a single whip antenna. I used 22AWG wire.
     
  3. mvs sarma

    mvs sarma Well-Known Member

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    Pardon me- A person of like AudioGURU, with his exposure to electronics and RF engineering, need not, I fear, be a radioHAM to be able to answer me or us in the field of RF.

    In technical society, there are eminent persons in in RF and AudioGURU is no less. . RadioHAM is only a practical experimentation of RF theory.
     
  4. dave

    Dave New Member

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  5. HiTech

    HiTech Well-Known Member

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    ^^^^ wut? lol :confused:
     
  6. audioguru

    audioguru Well-Known Member Most Helpful Member

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    I have made only two transmitters in my life. They were both FM transmitters.
    The first one was from a magazine.
    The second one was when I fixed then improved a defective one and copied things from others.

    An RF expert on another website boosted the output power of my transmitter 10 times and reduced its harmonics by adding many parts. I don't want more output and I don't want more parts.
     
  7. tytower

    tytower Banned

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    Fair enough mate.
    I just wanted to see if you had tried . I might do so and I fear you will be pretty right anyway. I will not be able to discern any appreciable difference.
    Same applies to verticals and horizontal antennas of all kinds- people using dipoles get the same effect with smaller diameter wire.
    Thanks
     
    Last edited: Jan 10, 2008
  8. anilgupta

    anilgupta New Member

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    dear audioguru

    i have builed many sort rang transmetere but i have no idea how can i increas range of transmeters suppose i want 5km range of thansmeters than what i do for this. so pl send us suggestion for this.
     
  9. simrantogether

    simrantogether New Member

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    One question...

    Hi,

    One question has always been with me...

    I can get a resistor , can get a capacitor of a certain value...

    Can we get an inductor of 0.1 uH as shown in first picture..

    Regards,

    Simran..
     
  10. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    You 'could', but it would be a pointless exercise, paying good money for a few turns of wire round a pencil!.Toko make such coils.
     
  11. mvs sarma

    mvs sarma Well-Known Member

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    Why take the risk of being caught by cops and move around courts stopping your education or job, Sir?
     
  12. audioguru

    audioguru Well-Known Member Most Helpful Member

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    If you transmit a powerful FM signal then its harmonics will cause TV interference to many people. Then you will be in trouble.

    It will be easy for the RF cops to find you. Then they shoot you and chop off your head.
     
  13. ftsahin

    ftsahin New Member

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    :)

    Bad cops huh ?
     
  14. audioguru

    audioguru Well-Known Member Most Helpful Member

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    No.
    The people who cause radio and TV interference are bad.
     
  15. batusai2425

    batusai2425 New Member

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    hi anyone,, can you pls send me a walkie talkie schematic tnx.appreciate it a lot.
    here's my email add batusai2425@yahoo.com
     
  16. audioguru

    audioguru Well-Known Member Most Helpful Member

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    A cheap walkie talkie is a child's toy. its range is only 100m.

    Good tranceivers are made, are inexpensive and have a range of 13km and more. You won't find the parts to make them and won't be able to design and align the complicated circuit.
     

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  17. zlatkoA

    zlatkoA Banned

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    right stuff

    your fm transmiter is very good,bravo and sorry for bad words...:) :)
     
  18. roykik

    roykik New Member

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    well,I'm going to build this one.
     
  19. petrv

    petrv New Member

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    Hi,

    If you are looking for more ideas about building FM transmitters, look here:

    http://pira.cz/eng/

    PiRa = Pirate Radio :)

    I haven't built any transmitter from that site but I believe it would work - just be careful that operating such transmitters can be illegal ...

    There is a description on that site of a very simple frequency counter which I have built a few years ago and it works very well so I believe the transmitters would work as well.

    Petr
     
  20. locust

    locust New Member

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    What kind of board is your circuit assembled on? I have never seen one like that. Is it soldered or wire wrapped? It looks really cool.
     
  21. audioguru

    audioguru Well-Known Member Most Helpful Member

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    My FM transmitter is made on Stripboard. It is perforated and has parallel copper strips. The copper strips are cut at a hole then the remainder of the strip is used for another part of the circuit. The strips make half a pcb and the parts and a few jumper wires make the remainder of the pcb. Each hole has a single wire in it.
     

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