+ Post New Thread
Results 1 to 7 of 7
  1. #1
    Newbie level 3
    Points: 23, Level: 1

    Join Date
    Jan 2020
    Posts
    3
    Helped
    0 / 0
    Points
    23
    Level
    1

    How to design a DC block circuit

    I repair Satellite receivers and I often need to block the DC voltage on the IF line to do the repair . I need to block 13-18 Volts between 900mhz and 2Ghz while obviously letting the AC signal pass. If anyone can suggest a simple circuit I would greatly appreciate it.

    •   AltAdvertisement

        
       

  2. #2
    Junior Member level 1
    Points: 1,232, Level: 7

    Join Date
    Nov 2013
    Posts
    17
    Helped
    1 / 1
    Points
    1,232
    Level
    7

    Re: How to design a DC block circuit

    I have a bit curious, why do you need to block DC on IF line ?
    IF line in satellite receiver is on feeder, right? which repair method do you apply without DC voltage ?



    •   AltAdvertisement

        
       

  3. #3
    Super Moderator
    Points: 81,102, Level: 69
    Achievements:
    7 years registered
    Awards:
    Most Frequent Poster 3rd Helpful Member

    Join Date
    Apr 2014
    Posts
    16,451
    Helped
    3732 / 3732
    Points
    81,102
    Level
    69

    Re: How to design a DC block circuit

    Hi,

    The usual way to block DC is a capacitor, connected in series.

    Klaus
    Please donīt contact me via PM, because there is no time to respond to them. No friend requests. Thank you.



    •   AltAdvertisement

        
       

  4. #4
    Newbie level 3
    Points: 23, Level: 1

    Join Date
    Jan 2020
    Posts
    3
    Helped
    0 / 0
    Points
    23
    Level
    1

    Re: How to design a DC block circuit

    Quote Originally Posted by Sattek View Post
    I repair Satellite receivers and I often need to block the DC voltage on the IF line to do the repair . I need to block 13-18 Volts between 900mhz and 2Ghz while obviously letting the AC signal pass. If anyone can suggest a simple circuit I would greatly appreciate it.
    I forgot to mention that the circuit impedance is 75 ohm.



  5. #5
    Advanced Member level 5
    Points: 14,848, Level: 29

    Join Date
    Apr 2014
    Posts
    2,311
    Helped
    929 / 929
    Points
    14,848
    Level
    29

    Re: How to design a DC block circuit

    As Klaus mentioned, just use a 100pF series capacitor.



    •   AltAdvertisement

        
       

  6. #6
    Newbie level 3
    Points: 23, Level: 1

    Join Date
    Jan 2020
    Posts
    3
    Helped
    0 / 0
    Points
    23
    Level
    1

    Re: How to design a DC block circuit

    Quote Originally Posted by volker@muehlhaus View Post
    As Klaus mentioned, just use a 100pF series capacitor.
    What about the circuit impedance? It needs to be coupled properly.

    Thanks



  7. #7
    Super Moderator
    Points: 81,102, Level: 69
    Achievements:
    7 years registered
    Awards:
    Most Frequent Poster 3rd Helpful Member

    Join Date
    Apr 2014
    Posts
    16,451
    Helped
    3732 / 3732
    Points
    81,102
    Level
    69

    Re: How to design a DC block circuit

    Hi,

    You may calculate the impedance ...

    Klaus
    Please donīt contact me via PM, because there is no time to respond to them. No friend requests. Thank you.



--[[ ]]--