Changing the output power of a radio circuit

Discussion in 'Wireless & RF Design' started by Brian D, Jul 23, 2016.

  1. Brian D

    Thread Starter New Member

    Jul 23, 2016
    I have this schematic for a 27mhz radio transmitter it just sends a signal that is then received and turns an led on when the button is pushed down. what I want to know is how do I change this circuit using the simplest method to change how much power is outputted. for example if I wanted more transmitting power what do I need to change or add and if I want less power what do I change or remove. Capture.PNG
  2. AlbertHall

    Distinguished Member

    Jun 4, 2014
    Reducing the output power is fairly simple and safe. Use an attenuator pad between the transmitter and the aerial.

    Some caution may be required when increasing the output power. Depending on your jurisdiction, there will be regulations on output power, harmonics and spurious outputs.
    You could increase the output power by a reasonable amount by increasing the supply voltage. To get a greater increase than is achievable that way you will need to add an extra power output stage.
  3. DickCappels


    Aug 21, 2008
    Or just shorten the antenna, and probably increasing R7 and/or R2 will reduce output as well.
  4. upand_at_them

    Active Member

    May 15, 2010
    Raise or lower the battery voltage?
  5. radiohead

    Senior Member

    May 28, 2009