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    This is a simple 27MHz FM-CB receiver circuit built with TCA440 for listening CB ( citizen’s band ) transmissions with FM (frequency modulation). The selection is made with ceramic filters. This 27 MHz receiver works with an intermediary frequency of 455 kHz. The input filter is 27 MF type, so we obtain an acceptable attenuation of the mirroring frequency.

    CB 27MHz Receiver Circuit Schematic

    cb fm 27mhz receiver circuit diagram

    Because the intermediary frequency filter is used without adapting transformer, the selection is at 40 dB. Because of the noise in the transmission pauses, the CB receiver circuit has a squelch circuit which reacts at 4.5 kHz domain noise.

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    10 Responses to "27MHz CB Receiver Circuit"

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    1. Where is the coil winding details????????????

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    2. There are no details, the coil has a serial number KXC/K3265

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    3. i don’t understand the cct

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    4. he he the most disgusting part of a transmitter the coil isnt explaned

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    5. Just one more circuit copied from Elektor without giving credit to the magazine.

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      • Ted, please send us more information about your comment because we are receiving emails with these circuits in pdf formats and then publish them. If it is from Elektor we will give them credit or remove the article if necessary. Use the Contact Us page.

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      • You can recognize Elektor schematics from their appearance; this one is certainly coming from that magazine.
        Anyway, besides the hard to find coil, both ceramic filters tuned at 27 MHz (FI1 and FI2) will be nearly impossible and/or expensive to get.

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    6. Never mind the magazine credit, WTF is this :|
      “…for listening CB ( citizen’s band ) transmissions with FM (frequency modulation…”
      FM ? On Citizen’s Band ?
      Dear friends, THERE IS NO FM on the 27Mhz Citizen’s Band!
      There may be SSB – Single Side Band, which was institued when they went from 23 to 40 channels, but the first 23 are Amplitude Modulated, not Frequency Modulated.
      IMHO, that is…

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    7. hassan delghavi says: on March 26, 2014 at 4:52 pm

      hi to every one i am comment from Iran please help me about one simple 27mhz receiver map pll . schématic diagram
      thank you very much .

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