[TowerTalk] ladder line vrs coax

k0dan k0dan at comcast.net
Thu Feb 9 23:06:23 EST 2006


You don't say what frequency you wish to operate on, but...

If you have a very long run of feedline, the ladderline will have lower
losses, but you need a balund and/or tuner to get it to 50 ohms at your
transmitter.

The coax fed dipole should have a pretty decent impedance match (L=468/F)
for one band. It will only preform well as a multiband antenna on 3X
mutliples of the resonant freq (ie 7 Mhz dipole also works well at 21 MHz).
The same antenna, fed with ladderline, should be a decent allband antenna,
assuming you have decent tuner to match impedances.

Type of ground, proximity to ground, trees, etc., are all variables, but
lots of sub-standard wire configurations can work pretty well.

At 28' high, your "inverted parallel dipole" (you mean, and inverted-V?) is
too close to the ground for almost every HF frequency (might be OK on 10-15M
if cut for those bands, but both those bands are kind of dead now), so you
will have ground losses and the takeoff angle will be pretty vertical.
However, depending on the freq you have the wire cut for, and what type of
contacts you wish to make, a vertical radiator can work pretty well for
close-in contacts.

Bottom line, if this is all you can put up, go for it, learn to know how it
performs, and enjoy it!

Good luck and 73

Dan
K0DAN


----- Original Message -----
From: "Merlin-7 KI4ILB" <merlin-7 at sc.rr.com>
To: <TOWERTALK at contesting.com>
Sent: Thursday, February 09, 2006 5:40 PM
Subject: [TowerTalk] ladder line vrs coax


> I am a bit confused here.
> I have an inverted  parallel dipole setup now fed by coax with an air
wound coke at the feed point.
>  the feed point is about 28' high and the ends are about 18' high.
>  I picked up a flat top kit fed with ladder line.
>
> What are the pros and cons between the two other than less loss on the
flat top?
>
>  Thanks
>  Joe
>  KI4ILB
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