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Thread: problem connecting a Mitsubashi amplifier to the HC-12 transmission circuit

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    Default problem connecting a Mitsubashi amplifier to the HC-12 transmission circuit

    Hello guys, I have a problem connecting a Mitsubashi amplifier to the HC-12 transmission circuit. I connected the power coming from the circuit to the amplifier directly, so the circuit became warm, knowing that the amplifier is set as shown in its data sheet, and the transmitter power in the circuit HC_12 is 25 mw. This is the link

    iDoes anyone have an idea of the correct method of fastening?
    Last edited by naseromar; 29-06-20 at 09:36 AM.



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    Uh.. that module requires a certain PC board with support components, a heat sink, voltage bias adjustment. Did you look at the manufacturers data sheet?

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    Quote Originally Posted by RFI-EMI-GUY View Post
    Uh.. that module requires a certain PC board with support components, a heat sink, voltage bias adjustment. Did you look at the manufacturers data sheet?

    Indeed...I did fine some homemade references, but I guess this is what you were referring to


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    Quote Originally Posted by wotnot View Post
    Indeed...I did fine some homemade references, but I guess this is what you were referring to

    That module requires a heatsink. The transceiver you have is 100 milliwatts so be sure to attenuate if required for the module. What are you going to do for a TR switch? Hard to transceive without a TR switch unless your app is TX only.

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    Quote Originally Posted by RFI-EMI-GUY View Post
    That module requires a heatsink. The transceiver you have is 100 milliwatts so be sure to attenuate if required for the module. What are you going to do for a TR switch? Hard to transceive without a TR switch unless your app is TX only.

    Sent from my SM-T350 using Tapatalk
    Thank you guys for interacting
    I read the datasheet well, but there are only four capacitors, two in a VGG leg and two in a vdd leg. It is mentioned that the circuit can be connected to the power source directly and that the input impedance is 50 ohms like the output of the transmitter circuit but the TR switch in the transmitter board be hot
    As for the vGG voltage, I installed a 5V voltage regulator and a variable resistance to calibrate the voltage. It was mentioned in the data sheet that it can be controlled from 2.5 to 3.5 to determine the output power. I did not exceed these limits. also i limted transitter power to 25mw
    i add heatsink and fan but the amplifir be hot
    I just wan t a transmission circuit, that is, I don't need a TR switch. I searched a lot for a circuit for this amplifier, but I find pictures without explanation so I hope one of you will mention to me the work of these added parts (diode and capacitors) that are not mentioned in the data sheet and their values.

    My expressions may be unclear because I do not speak English well
    Last edited by naseromar; 30-06-20 at 12:13 PM.

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    Designing a PCB for a RF transmitter is possibly beyond the scope of this forum, and without that understanding explaining the functions of various support components is a moot point.

    If I were doing this, I'd just buy a kit and be done with it -->

    Perhaps RFI-EMI-GUY can give some quick, wise words...but all I can say, is without the proper test gear, designing an amplifier board (RF or otherwise) is not as straight forward as you might think...ie; your module may well be running hot, because the circuit is oscillating madly, because there's no support components/groundplane/etc/etc/etc to define the operating conditions.

    Last edited by wotnot; 30-06-20 at 03:20 PM.

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    I concur. It is best to use one of those kits specific to the module you are using.

    If you don't mind sending an actual photo of what you have built so far, as well as the test gear being used to measure power, etc,

    The module will get warm as it is only so efficient, gives up extra power consumed as heat. A suitable heat sink is important to prevent module damage.

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