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    Matching 75ohm antenna to 300ohm receiver

    Hello i have this rabbit ear antenna and i want to connect it to my 300ohm receiver input. i wont use the 300 to 75 ohm balun but as i know the open dipole antenna is 75ohm but here its connected to a 300ohm cable .do i miss something here?How to match it properly to 300ohm balanced cable?
    Last edited by geotFM; 17th May 2019 at 08:59.

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    Re: Matching 75ohm antenna to 300ohm receiver

    Interesting observation. The only thing that comes to mind is that since the mismatch is not so high (~2dB) hence balun this is not included. Maybe to save cost?

    For Transmitter however, it would be important.



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    Re: Matching 75ohm antenna to 300ohm receiver

    Open Dipole Antenna has approx. 300 Ohm Impedance but there is a Balun in the TV Connector



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    Re: Matching 75ohm antenna to 300ohm receiver

    Quote Originally Posted by BigBoss View Post
    Open Dipole Antenna has approx. 300 Ohm Impedance...
    This is contrary to all known calculations and empirical evidence.
    This IS true for a closed (folded) dipole.
    Last edited by kripacharya; 17th May 2019 at 15:32.



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    Re: Matching 75ohm antenna to 300ohm receiver

    Here is the deal. If your length of 300 ohm cable is short (less than 1/8 wavelength) it does not matter.

    Only if you have a long transmission line is it a concern

    Balanced to unbalanced conversion is more important than impedance matching. An unbalanced load can screw up a dipole’s performance something fierce



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  6. #6
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    Re: Matching 75ohm antenna to 300ohm receiver

    Are you sure it's a 300 ohm line? What is the wire diameter, and the wire spacing??

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    Quote Originally Posted by biff44 View Post
    Here is the deal. If your length of 300 ohm cable is short (less than 1/8 wavelength) it does not matter.

    Only if you have a long transmission line is it a concern

    Balanced to unbalanced conversion is more important than impedance matching. An unbalanced load can screw up a dipole’s performance something fierce
    Good point. So in this particular case the antenna is obviously balanced and so is the cable. But that connector looks like an unbalanced 75ohm. There's probably a balun hidden inside that black end-plug

    - - - Updated - - -

    You should open it up and have a look-see



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