Need Help AM Transmitter & Receiver

Discussion in 'Wireless & RF Design' started by ahm7373, Dec 26, 2012.

  1. ahm7373

    Thread Starter New Member

    Dec 26, 2012
    1
    0
    Could anyone help me

    I need an AM Transmitter & Receiver working in 200KHz to 300KHz


    anyone have a schematic for this project?




    Thank you all
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,163
    1,796
    There's not much utility in that frequency range so I imagine there won't be very many contemporary circuits. You might try back issues of QST from the 1920's or 1930's. The antennas you might use are going to be large and cover a wide area, and you need to get them up pretty high in order for them to be effective. Then there is the legal problem of not having the right to operate a transmitter there.

    In the not too distant future an Amateur Radio License might get you a spot on the 2200M band, but an AM station there will be out of the question. Slow CW will be the order of the day.
     
  3. TecknoTone

    New Member

    May 20, 2012
    21
    1
    Is that necessarily the case? For instance, in this part of the world where we spell licence with two 'c's, we have MPT 1337 which has been superseded by ETSI Standard EN 300 330.
    It describes Low power transmitters and receivers for use in the frequency bands 0 - 185 kHz and 240 - 315 kHz allocated for use with low power induction communications and control systems
     
  4. Papabravo

    Expert

    Feb 24, 2006
    10,163
    1,796
    There is quite a bit of daylight between what the OP asked for and the short range stuff that those specs are talking about.
     
  5. tinamishra

    New Member

    Dec 1, 2012
    39
    1
    Amplitude Modulation (AM) is a form of modulation in which the amplitude of the carrier wave is varied in direct proportion to that of a modulating signal. AM was the first method used to broadcast commercial radio. This example illustrates how AM modulation and demodulation works.

    AM Receiver.vi is the receiver for the AM Transmitter.vi. It is just like any AM radio, but it receives signal using NI-SPEEDY 33 microphone instead of an antenna. This VI demodulates the modulated music that is "broadcasted" by the AM Transmitter.vi.
     
  6. tinamishra

    New Member

    Dec 1, 2012
    39
    1
    A model demonstrating the transmission of an AM signal that is then passed through a detector and filter circuit, with a graph displaying the signal and carrier wave.
    Total Harmonic Distortion is a measure of non-linearity in an audio system and is calculated as the RMS voltage of all the harmonics divided by the test tone RMS voltage multiplied by 100%.. The THD of my AM transmitter over the air signal as received by two receivers was measured.
     
  7. Papabravo

    Expert

    Feb 24, 2006
    10,163
    1,796
    @tinamishra -- Your posts seem relatively devoid of useful content. Do you have a circuit for a useful AM receiver and transmitter for the 200-300 kHz range. I know I don't, because such a device cannot be operated legally in the US at this time. The FCC (Federal Communication Commission) is considering an allocation in the 2200M band which would make a VLF project much more attractive.

    http://en.wikipedia.org/wiki/2200-meter_band

    Problem is that the entire band is 2.1 kHz wide and a conventional AM signal takes about 10 kHz. Even SSB takes 2.4-2.8 kHz.
     
  8. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    A throat microphone produces only low frequency vowels. It would work with the very narrow bandwidth but nobody would know what is being talked about. The consonants sounds of speech carry the intelligence and extend up to about 14kHz.
     
Loading...