[TowerTalk] ladder line vrs coax

Merlin-7 KI4ILB merlin-7 at sc.rr.com
Fri Feb 10 22:04:39 EST 2006

I was not planing on using any coax at all. My antenna tuner has conections
for bal. line.
 Is there a problem using this connection without a balun?
 Also the tuner is grounded.

> I'd vote for a flat top dipole as high as you can get it, with ladderline
> feed (or a variety of loops, as others have suggested). 300 ohm or 450 ohm
> line will be an easier match than 600 ohm. You can bring the ladderline to
> balun, then your tuner. You may have to experiment with different lengths
> for the ladderline...1/2 wavelength feedline at lowesat freq is ideal
> for velocity factor), avoid 1/4 wavelength.  Also, once in the shack, try
> keep your coax lengths as short as possible as well.
> A grounded tuner is less than optimal for keeping open wire line balanced
> balanced or link coupled tuner is better for this, but you might get by).
> Stray pickup by the ladderline should only be a problem if it is seriously
> out of balance. If the currents are equal & opposite in both legs, the
> feedline line should neither radiate nor pick up signals. Make sure both
> dipole elements are the same size and heigh above ground. Avoid proximity
> trees and other objects. Try to have the feedline drop vertically from the
> center of the antenna, don't let it run parallel to or get close to the
> dipole elements. There is plenty on this topic online and in the various
> handbooks.
> Goodluck & 73
> Dan

More information about the TowerTalk mailing list