I might be INSANE with this one

Discussion in 'Wireless & RF Design' started by jhave_21, Oct 20, 2017.

  1. jhave_21

    Thread Starter New Member

    Sep 14, 2017
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    hi, I think I'm insane right now, I wanna build my own RF transceiver, that runs at 2.4 ghz, could send 300 bytes of data, and a very high speed, and if possible with a 10 km range at least, I have a little bit of understanding of how everything works, (theories about radios) but I don't if how does the circuit works, I mean what part (electronic components )of the transceiver
    makes it send and receive data,
    I'm looking for tutorials online but all of it was all about theories I would like to know how the circuit works,
    if you have any tutorials, links , videos, or if you have any knowledge, where I can start with please help me,

    thank you
     
  2. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
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    The magic word here is modulation which means using the data to alter the RF carrier in some way. The simplest is probably ASK (amplitude shift keying) where the data simply turns the transmitter on and off (like the early morse systems used). There is also FM (frequency modulation) where the transmit frequency is varied by the data. There are plenty of others but they get increasingly complicated so you would probably want to choose one or other of those.

    If you transmit enough power at 2.4GHz to reach 10km you are going to wipe out all your neighbours wifi and, depending where you are in the world, break the rules for such transmissions.
     
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  3. jhave_21

    Thread Starter New Member

    Sep 14, 2017
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    I don't know man maybe I should start knowing how does the real circuit works to know if I can make my own.
    do you have any links for me to understand how does these circuit works (no matter what modulation types )

    I just wanna know how exactly these circuit works, I read and watched some tutorial, but they all give me a bunch of theories(which I already know)

    but thanks for the reply..
     
  4. AlbertHall

    AAC Fanatic!

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    Here's a simple example ASK transmitter. T1 is an oscillator and T2 is the output amplifier. The data is fed in to CN2. When CN2 is 0V there is no bias for T1 so it doesn't oscillate and there is no transmission. When CN2 is positive it provides bias for T1 which oscillates and so power is transmitted.
     
  5. jhave_21

    Thread Starter New Member

    Sep 14, 2017
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    thank you I understand a bit, but what about the other stuff, the capacitors and resitors,
     
  6. Papabravo

    Expert

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    They should be the smallest surface mount parts you can find. I can't even see 0402 resistors anymore, but that is what you need to use. I recommend you get some decent RF/Microwave layout tools as well. Your chances of doing this on the cheap are.....well, limited.
     
  7. AlbertHall

    AAC Fanatic!

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    Building a microwave transmitter and receiver with 10km range from scratch is a difficult proposition. I wouldn't attempt it. If you cannot understand the simple example circuit then your chances of completing this project are nil. I would strongly suggest you either find a different way of doing this (bluetooth, mobile phone apps, back to bluetooth perhaps) or abandon the project.
     
  8. Papabravo

    Expert

    Feb 24, 2006
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    Don't forget to include the cost of a 30x rife scope to aim your beam antenna. It's what the very best microwave DX'ers use.
     
  9. jhave_21

    Thread Starter New Member

    Sep 14, 2017
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    well thanks for the feedbacks, I think maybe I can't do it, I would like these to be applied to some arduino so...
    I looked at some of the RF modules online and I've seen this nRF24L01. these would suppose to work just fine but the range has limits,
    sorry for the interruption,
    but do you think it would be possible for this RF modules to go beyond limitations, 10km. maybe.
    I read some stuff online and from what I read, you can increase the range of your transceiver by:
    * giving it more power = which is not good for me I wanna make it as low battery "eater" as possible
    * by giving it an directional antennas = some thing like yagi antennas maybe
    * or increase the sensitivity = which I don't know how.

    sorry guys, some of you right now might find these irritating but please....
    thanks a lot,
     
  10. bertus

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  11. jhave_21

    Thread Starter New Member

    Sep 14, 2017
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    hi, thanks for the links, I think that's quite useful, but will it extend the range of my needs?

    and which is better a biquad or yagi?
    and what if I have a yagi or biquad with me and a simple Dipole on the other would it play nice?
    ty
     
    Last edited: Oct 23, 2017
  12. BR-549

    AAC Fanatic!

    Sep 22, 2013
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    Go to Amazon. Search for "Electronic Communication" sixth edition.......by Shrader. Mind was $10.

    If you start at the beginning and study.......your questions will be answered.

    It takes a textbook(studied in order) to answer your questions.
     
  13. Motanache

    Member

    Mar 2, 2015
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    I would suggest X-band Ham radio (10GHz).
    Many documentation on the Internet
    But it behaves like light. Obstacles are not good.
     
  14. jhave_21

    Thread Starter New Member

    Sep 14, 2017
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    hi, I today I just wanna tell anyone here thank this post
    I found some circuit, a long time ago, I don't even know what it is but it made me understand a bit. here it is:
    schematic (1).png
    but the way I understand it is it mixes the wave from(I don't really know what it is) the Q1(a 27Mhz SAW), and the square wave that was created around the 555 timer IC, and then it creates a bias on the T2 transistor.

    Am I right?
    this was with me a long time ago, I downloaded it somewhere.
     
  15. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
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    When the '555 output is low there is no bias on T2 so it is switched off and there will be no transmission. When that output is high a bias current is supplied to T2 base and now this transistor can amplify the oscillator signal from T1, and you have transmission.
     
  16. jhave_21

    Thread Starter New Member

    Sep 14, 2017
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    thanks, looks like I'm starting to learn,
    weeks ago I don't know what's happening on this circuit,but with a simple of explanation brought me somewhere I never imagined
    thanks
     
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