Gobau? After 24 hours, the name came. Maybe another 48 and I can spell it correctly.

--
Crazy George
The attglobal.net address is a SPAM trap. Please change that part to: attdotbiz properly formatted.

Close. It's Goubau, from "Surface Waves and Their Applications to
Transmission Lines," J. Appl. Phys., vol. 21, 1950. An interesting
variation is described in "Low-Loss RF Transport Over Long Distances",
by M. Friedman and Richard F. Fernsler, IEEE Trans. on Microwave Theory
and Techniques, Vol. 49, No. 2, Feb. 2001, describing a system the
authors describe as "simple, inexpensive, lightweight, and [having] low
attenuation". They used a strip of aluminum foil 6 cm wide and 0.02 mm
thick with periodic punched holes as the line, strung it around a lab
with the strip suspended by threads, and measured low attenuation. How
this could translate to a practical outdoor system for "long distance RF
transportation" as the authors claim is beyond my feeble imagination.

Roy Lewallen, W7EL

Crazy George wrote:
Gobau? After 24 hours, the name came. Maybe another 48 and I can spell it correctly.

--
Crazy George
The attglobal.net address is a SPAM trap. Please change that part to: attdotbiz properly formatted.

On Fri, 08 Apr 2005 21:50:36 -0700, Roy Lewallen
wrote:

Close. It's Goubau, from "Surface Waves and Their Applications to
Transmission Lines," J. Appl. Phys., vol. 21, 1950. An interesting
variation is described in "Low-Loss RF Transport Over Long Distances",
by M. Friedman and Richard F. Fernsler, IEEE Trans. on Microwave Theory
and Techniques, Vol. 49, No. 2, Feb. 2001, describing a system the
authors describe as "simple, inexpensive, lightweight, and [having] low
attenuation". They used a strip of aluminum foil 6 cm wide and 0.02 mm
thick with periodic punched holes as the line, strung it around a lab
with the strip suspended by threads, and measured low attenuation. How
this could translate to a practical outdoor system for "long distance RF
transportation" as the authors claim is beyond my feeble imagination.

Darn it Roy, that's your problem... no imagination. These guys
apparently couldn't see the commercial applications either.

They should have written a companion article in Worldradio News about
the super performance they see when using this stuff to feed E-H and
Fractal antennas.

And if they had been really sharp they would have started a company
ahead of time---let's call it "Foilman"---(apologies to Press Jones)
and been ready to peddle this stuff to hams.

A coupla glowing reviews on eham.com and the money would roll in.

Wes

ps. I going to go out and start punching holes in the elements of my
20-meter beam and see what happens.

Roy Lewallen wrote:
Close. It's Goubau, from "Surface Waves and Their Applications to
Transmission Lines," J. Appl. Phys., vol. 21, 1950. An interesting
variation is described in "Low-Loss RF Transport Over Long Distances",
by M. Friedman and Richard F. Fernsler, IEEE Trans. on Microwave Theory
and Techniques, Vol. 49, No. 2, Feb. 2001, describing a system the
authors describe as "simple, inexpensive, lightweight, and [having] low
attenuation". They used a strip of aluminum foil 6 cm wide and 0.02 mm
thick with periodic punched holes as the line, strung it around a lab
with the strip suspended by threads, and measured low attenuation. How
this could translate to a practical outdoor system for "long distance RF
transportation" as the authors claim is beyond my feeble imagination.

In a Beverage antenna, how much transmit power is lost in the
terminating resistor? We know a Beverage is a very inefficient
transmitting antenna. Could it be because it's a fairly efficient
transmission line? Or is it because of ground losses?
--
73, Cecil http://www.qsl.net/w5dxp

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Cecil Moore wrote:

In a Beverage antenna, how much transmit power is lost in the
terminating resistor? We know a Beverage is a very inefficient
transmitting antenna. Could it be because it's a fairly efficient
transmission line? Or is it because of ground losses?

Model one with EZNEC to find out. At each end, put a few radial wires
just above the ground to connect the source and terminating resistors
to, and use High Accuracy ground. The Average Gain will tell you the
total loss which includes resistor and ground loss. Click the Load Dat
button to find the loss in the terminating resistor. From those you can
get the amount of ground loss.

Roy Lewallen, W7EL

Roy Lewallen wrote:
Close. It's Goubau, from "Surface Waves and Their Applications to
Transmission Lines," J. Appl. Phys., vol. 21, 1950. An interesting
variation is described in "Low-Loss RF Transport Over Long Distances",
by M. Friedman and Richard F. Fernsler, IEEE Trans. on Microwave Theory
and Techniques, Vol. 49, No. 2, Feb. 2001, describing a system the
authors describe as "simple, inexpensive, lightweight, and [having] low
attenuation". They used a strip of aluminum foil 6 cm wide and 0.02 mm
thick with periodic punched holes as the line, strung it around a lab
with the strip suspended by threads, and measured low attenuation. How
this could translate to a practical outdoor system for "long distance RF
transportation" as the authors claim is beyond my feeble imagination.

Heh, heh, maybe they modeled it with NEC2. Violating the
height above Mininec ground rule yields a source power of
396 watts and a load power of 340 watts (86% efficiency)
for a 1000 foot line, one foot above ground, on 20m. :-)
(While yielding a Beverage antenna gain of 13 dBi)

How would it work between two ships on a calm ocean?

Can the single-wire transmission line be modeled with EZNEC
if the height is greater than 0.2 wavelength?

Can it be modeled with NEC4? If so, could someone do it
and report the results?
--
73, Cecil http://www.qsl.net/w5dxp


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Cecil Moore wrote:
. . .
Can the single-wire transmission line be modeled with EZNEC
if the height is greater than 0.2 wavelength?

Can it be modeled with NEC4? If so, could someone do it
and report the results?

I don't think either program can model it. Single wire transmission line
operation depends on an interaction among the field from the wire
current, the insulation, and the air, that NEC-2 and -4 don't model. The
wire insulation calculation provided by EZNEC and NEC-4 only calculates
the effect of insulation on wire impedance, not on how the field
launches from the wire. You might be able to do it with a 3D field
solving program (which, last I heard, were in the $20k+ category).

Roy Lewallen, W7EL