[Antennas] Simple dipole

[Robert Lay (W9DMK)]

Dear Milt,


> The 300 Ohm twin lead and the 450 Ohm ladder line are common impedances 
> for which 6:1 and 9:1 baluns are available "off the shelf".  The natural 
> impedance of a folded dipole is ~ 300 Ohms, so making it of 300 Ohm 
> impedance cable and feeding it with 300 Ohm balanced cable or 50 Ohm 
> unbalanced cable through a 6:1 balun is the common method for which 
> components are readily purchaseable, or for which there are textbook 
> articles describing their construction.

You seem to be under the impression that there is a majority of antennas 
being fed with balanced line that use a balun at the antenna end. I don't 
remember ever seeing such. In fact, in those instances where baluns are 
used, it is usually at the tuner end - not at the antenna end.

So, again, I ask, why are you presuming that everyone using balanced lines 
are doing it incorrectly.

For me, personally, I could care less whether I have a good match or not at 
the antenna end of the line. That's why I use balanced line - because it is 
relatively unaffected by the high SWR - certainly more so than is coax.

My rationale is that even if it IS a good match at this frequency or that 
frequency, it is going to be severely mis-matched at MOST frequencies.

Agreed?

73,
Bob