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RC frequency interference — Parallax Forums

RC frequency interference

ShoshiShoshi Posts: 1
edited 2008-03-05 14:47 in BASIC Stamp
I have two RC·cars with controllers·that operate on 49Mhz,
how do I·hack one of them to work on a different frequency ? do I have to replace the parts or can I somehow fix the frequency of one of them ?

Comments

  • FranklinFranklin Posts: 4,747
    edited 2007-10-15 00:15
    I would ask on a site that runs RC vehicles. You might get better answers. Also changing the frequency outside the official methods will probably violate the law.

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    - Stephen
  • DataFreedomDataFreedom Posts: 6
    edited 2008-03-05 10:38
    I would ask if it was digital or analog but after looking the LM1872N is a RC reciever and decoder IC. Respectivly used with LM1871N which is the transmiter.

    both have 2 analog channels and 2 digital channels

    the DataSheet 'http://www.ortodoxism.ro/datasheets/nationalsemiconductor/DS007912.PDF') is there.


    also, I dont think the RC signal transmission would effect much. The analog channles support the carrier wave and the digital channles are for the timing (ie pulse width ect.). the frequency is close enough to the amature radio (ham) band 50.0 that no one would notice.

    Post Edited (DataFreedom) : 3/5/2008 10:46:39 AM GMT
  • terry_bearterry_bear Posts: 84
    edited 2008-03-05 14:47
    Shoshi,

    There are several issues here. First, if you get out of the frequency that is allocated to these things you will be trespassing on the territory of some of other service. There are NO un-allocated frequencies below 2 Gzh! (I don't re-call if there is any "free range" left anywhere above that...

    That said, the frequency seems to be controlled by an external tank circuit and its primary component is a crystal. Frequency change would depend on how far you wish to change... Do you have the test equipment necessary to re-tune the transmitter and receiver to the same new frequency?

    You say that "the frequency is close enough to the amature radio (ham) band 50.0 that no one would notice" Actually, the only thing that allow you to "slide under the radar" would be the low power transmission of these things. The 50 Mhz ham band is sometimes used by hams for RC, and if you inadvertently shot down someone's plane, he (or she) would be (rightfully) rather perturbed...

    Regards,

    Terry
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