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Author Topic: Tilted Inductors at "The Magic Angle?"  (Read 3755 times)
W8JI
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« Reply #15 on: September 09, 2012, 10:31:35 AM »

A goniometer would be quite useful for a noise canceller, because of the 360 degree phase rotation available.

I researched this a little.

The goniometer injects no phase shift at all, other than a phase flip.

If field coils were excited in a phase relationship other than zero or 180, then the goniometer could mix the two differing signals in various amplitude relationships, which would rotate phase as the ratio being vector summed changed.

The reason it works with two small loops or Adcock arrays, to electrically rotate those arrays (it really only electrically turns them 180 degrees), is it mixes the signals from those sources in varying ratio. That's all it does.  

A pot would do the same thing, if levels could be maintained and if we added a phase flip switch.

This is very easy to model and prove in EZnec. Make two small vertical loops on the same vertical center with the axis of one horizontally in the X direction and the axis of the other in the Y direction. Make one very slightly higher so the wires do not bump into each other.

Now as current ratios are changed from 0 1 to 1 0, we see a 90 degree rotation in null. Now when the goniometer crosses the 1 for the first loop phase will abruptly flip 180 for the zero level loop. Now as level comes up the null moves past and completes another 90 degree swing.

This is what I recalled from the past, although that was before EZnec or computers were thought of.

The technically correct description would be the goniometer changes levels, with a 180 degree flip as one level crosses zero. This can be used to "rotate" two bidirectional antennas, but it really only rotates them 180 degrees. Since that moves one of the two nulls over 180 degrees, we can force a null at any heading (with one opposite).

We could shift phase in a goniometer if we excited the field coils with a phase relationship not zero or 180.

73 Tom
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KA4POL
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« Reply #16 on: September 09, 2012, 11:07:21 AM »

The so called Magic Angle of 54.7 degrees is the angle between the space diagonal of a cube and any of its three connecting edges. And interestingly it also plays a role for decoupling in Nuclear Magnetic Resonance spectroscopy.
So the answer on how they arrived at that angle would really be interesting. They did not know anything about NMR for sure.
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W8JI
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« Reply #17 on: September 09, 2012, 02:07:42 PM »

The so called Magic Angle of 54.7 degrees is the angle between the space diagonal of a cube and any of its three connecting edges. And interestingly it also plays a role for decoupling in Nuclear Magnetic Resonance spectroscopy.
So the answer on how they arrived at that angle would really be interesting. They did not know anything about NMR for sure.

I don't want to get into a thing about coils, but the angle of minimum coupling will vary with distance between the coils and offset of the coil centers. They must have had some specific application.

I know for a fact, from measuring coupling when there were problems, it isn't always 54.7 degrees any more than it is always some other angle. I'm not saying there aren't specific cases where it is 54.7, but I can think of two or three cases that were close to 90 degrees.   
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K7KBN
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« Reply #18 on: September 09, 2012, 06:35:01 PM »

Maybe I should see a patent attorney about ... well, it's a discovery I made...

Π®
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73
Pat K7KBN
CWO4 USNR Ret.
W8JI
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« Reply #19 on: September 10, 2012, 03:08:25 AM »

Maybe I should see a patent attorney about ... well, it's a discovery I made...

Π®

They patent anything that has not been written as prior art, even very old things. Things don't even need to work to be patented.
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G3RZP
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« Reply #20 on: September 10, 2012, 04:28:15 AM »

My experience of patents is that they are good for two things. They look good on your resume, and my last employer paid you $5,000 for each one granted. Admittedly, there was 40% income tax deducted....before the company was taken over, you got one dollar. Most of mine have expired because they don't pay the renewal fees any more.
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