"Martin H. Eastburn" wrote in
:

Remember cellphones. Analogs had wip antennas that you pulled out...

Then the digital trend - antennas were internal.

What happened - range dropped and dropped. Analog can be used for
miles. Digital is good for a mile or two. It is also absorbed by pine
trees and is almost line of sight.

Martin

Ed Huntress wrote:
"Mark Rand" wrote in message
...
On Sat, 26 Sep 2009 14:44:31 -0400, "Ed Huntress"

wrote:

What Justme said has been common knowledge to ham radio operators
for more than half a century. SWR doesn't matter much with ladder
line, partly because of its low loss and partly because most of the
antennas it's usually
feeding are no great shakes themselves, and radiation from the
transmission
line is tolerable. I switched from a balun-type coax-fed dipole to
a ladder-line-fed folded dipole once, both of them in the exact
same position,
and I got much better reports on the one fed with (300 ohm) ladder
line. And
I'm sure that the SWR on that line was out of whack.

But a folded dipole is nominally 300 ohm (292 ish). Am I
misunderstanding the
magnitude of "not mattering much"? I had the image of people
sticking a quarter wave stick on the end of a ladder line and
calling it good...

They might get away with it, too. g

At the HF bands most of us are familiar with, it's unusual to see
simple antennas that are high enough to avoid radiation distortion
and impedance distortion as a result of their proximity to the
ground. If you have a VSWR meter and a willingness to tune the whole
affair, you can get good matches all around. If not, you'd might as
well feed the antenna with a low-loss ladder line and be done with
it. You'll get more radiative power out, in most cases, even if some
of it is coming off of the feedline.

The best gadget for calculating VSWR & mismatch losses is a plastic
slide rule from Phil Smith's (inventor of the Smith chart) "Analog
Instruments" company. Phil passed away a number of years ago, but his
wife was still selling stuff a few years back. I've been an RF engineer
for decades, and despite all of the modern CAD tools, I still use that
slide rule once or twice a week. We've got a problem with an antenna at
work, and I've been able to run instant loss calculations in the middle
of a meeting. Besides, when I fish it out & give out numbers in a
meeting, it enhances my senior guru status considerably.

I bought a whole stack of the slide rules a while back to give to the
younger engineers, but I think my stash is about gone. Most of the
youngsters have been conditioned to find a computer, locate a VSWR
calculator on Google, discover it doesn't do what they want, find a
couple more, and then finally come up with an answer. I can usually walk
back to my office, grab my slide rule & have an answer in less time.

Doug White