74MHz FM transmitter

Discussion in 'The Projects Forum' started by Vincyoxy, Jul 23, 2009.

  1. Vincyoxy

    Thread Starter New Member

    Jul 23, 2009
    1
    0
    Hi Expert,

    I doing a standard FM transmitter circuit.
    And it only can transmit in the frequency band of 88MHz to 108MHz which is radio frequency.
    But i want to make a tranmitter to transmit in 74MHz.
    I thinking to modify the tank circuit. But is it possible? Or other method to modify the circuit?

    CHEERS=)
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    Do you have the schematic for us?
    Without the schematic it is more difficult to answer,
    as there are several types of oscillators.

    The frequency can be changed by tuning the circuits.

    Greetings,
    Bertus

    PS Is the 74 Mhz allowed for transmitting?
     
  3. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    I think 74MHz is in the FM broadcast band in Japan.
     
  4. millwood

    Guest

    you may want to think again on that.
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
    907
    The question still remains, why 74 MHz?

    Model aircraft are on 72 MHz, surface models are on 75 MHz, and the Naval Observatory VLA is on 74 MHz to name just a few users in that part of the spectrum.

    The circuit to which I think you are referring can be tuned fairly broadly and potentially cause interference with any of the legitimate users.

    Thus, if you are not licensed to work on 74 MHz, I do not think this forum should support your effort to build such a transmitter.

    John
     
  6. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    I was close but wrong.
    The FM broadcast band in Japan is 76MHz to 90MHz.
    It is 65MHz to 74MHz in former Soviet republics.
     
  7. DickCappels

    Moderator

    Aug 21, 2008
    2,664
    634
    Yes, if the frequency is determined by the tank circuit.
     
  8. bertus

    Administrator

    Apr 5, 2008
    15,652
    2,348
    Hello,

    If the transmitter has more stages, the amplifier stages will need adjustment too.
    You have not posted the schematic yet.

    Greetings,
    Bertus
     
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