On Thu, 12 Jan 2006 19:08:07 -0800, Dr. Anton T. Squeegee
wrote:
In article ,
says...
Nothing to do with coupling the Tx energy to the "atmosphere". Terminating the
line in a resistor of the line's charactertistic impedance will present a nice
SWR and radiate very little.
I beg to differ, and I would invite you to think further on this
topic.
An antenna is a coupling device. Its purpose is to efficiently
"couple" or radiate your signal into another transmission medium (open
space, including our atmosphere).
The antenna (effectively an inductor) needs to be resonant at your
operating frequency of choice. It seems to me that the density and
composition of the transmission medium you're coupling to has an effect
on any antenna's resonant frequency.
This, to my understanding, means that an antenna designed for use
in open air will not work underwater, nor will, say, a VLF antenna
designed for submarine usage work in open air.
If you believe I'm misunderstanding, then please point me to some
documentation on the subject, and I will cheerfully STFU.
Pity you snipped your original statement:
"SWR = Standing Wave Ratio. Put simply, it has to do with how good
of a load the antenna presents to the transmitter, and how efficiently
it will couple the transmitter's energy to the atmosphere."
Roy has kindly addressed the antenna aspects. But because you snipped, the
essence of my comment was cut adrift. A nice 50R resistor will not "couple the
transmitter's energy to the atmosphere" at all efficiently, but should certainly
provide a rather good match to your 50 ohm line. You should not attempt to
equate radiation efficiency with line matching.
I suggest you need to think further, or stick to plumbing.