Recently I have reconfigured a coaxial end fed antenna in an attic to a dipole fed with ladder line that goes directly to the balanced input of a vintage shortwave radio.
From what I read, the impedance of the center of the dipole is approximately 73 ohms but the ladder line is 450 ohms. Yet, there is no impedance matching required between the ladder line and the antenna. Why is that?
Also, it seems that it is recommended when feeding a dipole with coax, to use a 4:1 balun but I have also seen 1:1 recommended. But this does not seem to properly match typical 50 ohm coax (though TV coax would be closer in impedance).
Anyway, just confused on what the rules of thumb are for ladder line vs. coaxial fed dipoles going to a radio with a balanced input.
Lastly, doing a little experimenting I noticed that some frequencies come in better shorting one of the balanced posts to ground. On other frequencies, this makes reception worse. Yet on other frequenices, it makes little to no difference. Why is that?
From what I read, the impedance of the center of the dipole is approximately 73 ohms but the ladder line is 450 ohms. Yet, there is no impedance matching required between the ladder line and the antenna. Why is that?
Also, it seems that it is recommended when feeding a dipole with coax, to use a 4:1 balun but I have also seen 1:1 recommended. But this does not seem to properly match typical 50 ohm coax (though TV coax would be closer in impedance).
Anyway, just confused on what the rules of thumb are for ladder line vs. coaxial fed dipoles going to a radio with a balanced input.
Lastly, doing a little experimenting I noticed that some frequencies come in better shorting one of the balanced posts to ground. On other frequencies, this makes reception worse. Yet on other frequenices, it makes little to no difference. Why is that?