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ASK transmitters in parallel

  1. Nov 3, 2015 #1
    I have built a remote control car, pwm speed controll and all, using picaxe microcontrollers and gained a lot of experience doing it.
    I used a low power i think 20mw transmitter you can find all over ebay that uses a 433hz carrier wave. A long time ago i found a 1w transmitter meant to be a step up from the common 20mw i mensioned but if i do not want to use the larger 1W transmitter, then will 2 20mw transmitters double my range?
    It may seem like an obvious question but i lack in knowledge reguarding electrmoagnetic waves and such.
    Or will even using 2 recievers increase this sensitivity?
  2. jcsd
  3. Nov 4, 2015 #2


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    Science Advisor
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    Gold Member

    No you can't use two transmitter modules like that. Hard to know where to begin to explain but it won't work. The simplest answer is that the receiver will see two signals on the same frequency. One will appear as interference to the other making the range worse or non-existent.

    I've not used these 433MHz modules but getting the aerial length right will be important. It might be possible to double the length for example. Fine tuning the length may also be necessary. It may also be possible to turn up the supply voltage to the transmitter module (some modules only and at your own risk). Google found..


    Edit: Oh and well done for getting the project working!
  4. Nov 4, 2015 #3


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    Staff: Mentor

    What country are you in? You probably are not supposed to be trying to increase your power in the 433MHz band above that 10-20mW -- there are other users in that band, and you are limited to low power for a reason, to avoid interference.


  5. Nov 4, 2015 #4
    I am in the US and didn't realize there was a law so ill keep bellow 20mw.
    I really want a somthing plug and play, could I possibly take one f these modules and tap a mosfet amplifier circuit onto the antenna pin and take measurements in order to achieve a true 20mw thus using the module only for its encoder purpose and create a transmitter which will simply amplify the signal it creates and put that through a coil?
    or what about the zab-3000 transmitter?
  6. Nov 4, 2015 #5


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    Staff: Mentor

    You shouldn't try to make an amplifier unless you have access to an RF Spectrum Analyzer and know how to use it to be sure that your amp doesn't have any harmonics that would violate the FCC specs for out-of-band interference. If you want more range, just use the 2.4GHz stuff that was mentioned previously. You can use a fair amount more power in that band, I believe...
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