# Ever hear of the new "fractal antenna" designs ?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KD7SIZ, Dec 15, 2010.

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1. ### W1YWHam MemberQRZ Page

Considering we came first, it could hardly be a variation of that design, which it doesn't resemble anyway.

Also, do you understand WHAT their cloak is? Do you understand that it requires a grid of repeated objects AS THE THING TO BE cloaked?

Please: tell us how this in any way related to the practical realization of a wideband invisibility cloak shown at:

W1YW

Last edited: Jan 20, 2011
2. ### K4WGEHam MemberQRZ Page

Harry Potter and the Half-baked Prof

?

Is that why Chip failed to get tenure at Hogwart's?

3. ### W1YWHam MemberQRZ Page

Ahhh!

Number 2 AND Number 1--all rolled into one!

4. ### W8JIHam MemberQRZ Page

It is very common to measure things incorrectly and hatch a new invention or theory.

5. ### W5DXPHam MemberQRZ Page

Here's a good example:

http://www.w8ji.com/inductor_current_time_delay.htm

"Measure things incorrectly and hatch a new invention or theory", e.g. that the delay through a large air-core loading coil bears any resemblance to the standing wave current phase shift even when an extreme mismatch exists.

Pure standing wave current doesn't change phase over each 1/2 wavelength so it cannot be used to measure delay through a wire or through a coil. Reference: Antennas by Kraus, 3rd edition, Figure 14-2 where the actual current phase shift changes by 3 degrees over the entire 1/2 wavelength of a dipole (a standing wave antenna).

6. ### M3KXZHam MemberQRZ Page

"Current does not have to do with how far charges move in a second but rather with how many charges pass through a cross section of wire on a circuit............The rate at which charge enters the external circuit on one end is the same as the rate at which charge exits the external circuit on the other end. Current - the rate of charge flow - is everywhere the same. Charge flow is like the movement of soldiers marching in step together, everywhere at the same rate." (ref http://www.physicsclassroom.com/class/circuits/u9l2c.cfm )

Suppose a way to to make a comparison would be to use time domain reflectometry on a terminated line of a certain length, and then compare it with measurement on same length of line formed into a solenoid.

Last edited: Jan 20, 2011
7. ### N5RWJHam MemberQRZ Page

Hi Chip,seems like a lot of QRM on this topic today. Chip could you talk some on the future of Fractal antennas, also on Fractal antennas for 75,40, and 20 meters?

8. ### K1BQTHam MemberQRZ Page

"Perhaps you can articluate the process by which 'time tells'?"

I was thinking of the time-honored (and time-consuming) process of validation and verification that occurs normally within the scientific community. You know, like Cecil and Tom are doing right now!

9. ### W5DXPHam MemberQRZ Page

Unfortunately, that applies to a DC steady-state circuit, not to an RF distributed network. For a transmission line or coil that is 180 degrees long (series self-resonance) the rate of charge flow into one end of the coil is equal to the rate of charge flow into the other end of the coil.

10. ### W5DXPHam MemberQRZ Page

You mean like this graph of load current phase shift vs source current reference phase=0 through a Texas Bugcatcher coil as the load resistance is varied?

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