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Zenneck Waves




 
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WA4WAX
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« on: July 31, 2022, 12:38:51 PM »

An Optoelectronics M1 is not all that sensitive.  Yet we just about pinned the bar graph with 1V rms from my old 606A.  The foil on the floor was 75 feet long. It was tuned to the 6 meter band.

The experiments were performed at Coca Cola U about 4 months ago.


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WA4WAX
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« Reply #1 on: July 31, 2022, 12:40:23 PM »

Another  shot.  Now go find a BC-610 coil.



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WA4WAX
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« Reply #2 on: July 31, 2022, 02:33:45 PM »

The treat gets sweeter as you lower the frequency.  Someone ought to try 10 or 15 watts on 160m.
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WA4WAX
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« Reply #3 on: August 01, 2022, 12:15:06 PM »

I have the construction details available for interested parties.

Start around 100 mW or so.  Get an an old diode field strength meter with a whip antenna.

Instead of small copper balls, get a couple of copper pleated toilet tank floats. I would try 40 or 80 meters.

You will tune the input circuit for (series resonant link) with a NanoVNA or other suitable device.  Of course, the parallel output circuit will also be adjusted.

At a given frequency, there will be found a good "mode match" at a certain height above ground, and a certain spacin between the conductive balls.
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DMOD
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« Reply #4 on: August 01, 2022, 06:40:41 PM »

I have the construction details available for interested parties.

Start around 100 mW or so.  Get an an old diode field strength meter with a whip antenna.

Instead of small copper balls, get a couple of copper pleated toilet tank floats. I would try 40 or 80 meters.

You will tune the input circuit for (series resonant link) with a NanoVNA or other suitable device.  Of course, the parallel output circuit will also be adjusted.

At a given frequency, there will be found a good "mode match" at a certain height above ground, and a certain spacin between the conductive balls.

Just my opinion but I don't see how any of this Z-wave technology has any iota of relations to Amateur Radio.

Phil


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WA4WAX
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« Reply #5 on: August 01, 2022, 08:58:15 PM »

Phil:

I am going to try it on 40 meters.  The idea is to see what kind of range.  If range is good, it would be very useful to Hams.

Nothing ventured, nothing gained.
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w3jn
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« Reply #6 on: August 01, 2022, 09:44:32 PM »



Just my opinion but I don't see how any of this Z-wave technology has any iota of relations to Amateur Radio.

Phil



Maybe some context or at least an explanation of what this is all about would be helpful?Huh
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« Reply #7 on: August 02, 2022, 06:28:58 AM »

I had the same question - what the hell is being discussed here?

Well here’s a little background:

https://www.popularmechanics.com/technology/infrastructure/a8778/skimming-the-surface-the-return-of-teslas-surface-waves-15322250/
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Chris, AJ1G
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WA4WAX
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« Reply #8 on: August 02, 2022, 12:32:59 PM »

I am discussing the Zenneck wave device in the pictures.  It was tested about 4 months ago.  A series/Parallel circuit is connected to the two copper balls via a 1/2 wave line.

I want to try it out in the open on one of the lower bands. 

https://www.jensign.com/surfacewave/
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WA4WAX
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« Reply #9 on: August 02, 2022, 03:45:14 PM »

If I get some decent range on the next test, who would be up to come and see it?
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Pete, WA2CWA
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« Reply #10 on: August 02, 2022, 06:11:22 PM »

Surface waves, i.e. ground waves, aren't some new revelation.

Wave propagation over a surface isn't new. At HF frequencies, it probably would be difficult to keep the signal from just moving along the surface and not radiating up into the ionosphere.
Wave guides at microwave frequencies have been used for a long time.
A wave guide can consist of a rectangular or cylindrical metal tube, pipe, or sheet. The electromagnetic field can propagate lengthwise over the surface. Bandwidth, to some degree, can be controlled by its width.

I seem to recall doing material surface wave guide experiments in my college physics class back around the beginning of time.

I still like propagating my signal the old fashion way. Don't need a lot of math to figure it out because too much math hurts my brain.
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« Reply #11 on: August 02, 2022, 06:39:09 PM »

Just when you thought it was safe to dig into 'alternative waves', a reference to J.C. Maxwell's Scalar Waves as discussed in the 1st edition of his book pops up Huh.

73DG
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Pete, WA2CWA
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« Reply #12 on: August 02, 2022, 07:32:29 PM »

Here's a wave:

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« Reply #13 on: August 02, 2022, 08:50:55 PM »

One never knows what is possible; a friend of mine has demonstrated full duplex, realtime video/audio wireless linking at the bottom of a very deep mine.

73DG
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« Reply #14 on: August 03, 2022, 06:00:50 PM »

If I get some decent range on the next test, who would be up to come and see it?

I guess I have to ask the obvious questions;

Q1: How do you know you are launching the Transverse Magnetic Mode 0 (TM0) and how do you know you will be detecting that TM0?

Q2: On another thread you were wanting to know Pi-net values for a 300 meter band circuit but here you say you will be using the 40m band. What's the connection?

Phil
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WA4WAX
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« Reply #15 on: August 04, 2022, 03:43:02 PM »

Phil:

Know for sure that it is TM0?  I might need some uptown instruments to convince people of TM0. BTW, there is no cut off frequency in a surface wave scheme as opposed to waveguide.

As to a surface wave: Swing the needle on a crystal diode FSM with low power from a distance is pretty telling.  Directivity is also telling, and it was in evidence in that hallway.  When I would move off the axis of the foil, the signal would drop precipitously.  The Optoelectronics widget has a minimum sensitivity of 2 mV.  When you are just about pegging it from 75 feet away with 1 V RMS into 50 ohms, that is prolly not Hertzian.

Now to your other question: Before I tackle the 400 KHz build, I am going to run the old 606A into a new probe built around a BC-610 coil tuned to 40 meters.  The conductive spheres will be larger.  I am going to try to launch a wave using the air/sod interface.  For detection, I will use an old Lafayette tuned crystal diode FSM.

We shall see......................
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WA4WAX
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« Reply #16 on: August 04, 2022, 03:48:48 PM »

If I get a good air/sod result, it will be a boon for Hams....especially on 160m.
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DMOD
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« Reply #17 on: August 05, 2022, 02:29:51 AM »

Phil:

...Know for sure that it is TM0?  I might need some uptown instruments to convince people of TM0. BTW, there is no cut off frequency in a surface wave scheme as opposed to waveguide....

Yes according to these two papers:

http://www.corridor.biz/FullArticle.pdf

https://www.jensign.com/surfacewave/

Phil

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WA4WAX
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« Reply #18 on: August 05, 2022, 11:04:20 AM »

Folks will have much fun if this works well on the air/sod interface.

One potential problem: Uncle Charlie.
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DMOD
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« Reply #19 on: August 05, 2022, 05:21:48 PM »


Know for sure that it is TM0?  I might need some uptown instruments to convince people of TM0.

Yes as explained here:

"Zenneck Surface Wave
The Zenneck surface wave is an inhomogeneous plane wave supported by a flat surface. It is a transverse magnetic (TM) mode and requires that the permittivities of the media either side of the interface are different but their permeabilities are the same. It also requires an inductive reactance term in the surface impedance, Zs for the medium it propagates along.

In order to excite a TM Zenneck surface wave, two conditions are required:
1. incidence close to the Brewster angle;
2. finite loss in one of the media. "

https://www.armms.org/media/uploads/1259319847.pdf

Phil
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DMOD
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« Reply #20 on: August 05, 2022, 05:47:22 PM »

Folks will have much fun if this works well on the air/sod interface.

One potential problem: Uncle Charlie.

Did you not read my response to you in the "809" thread?

http://amfone.net/Amforum/index.php?topic=47628.0

I have to apply for these occasionally and with supporting documentation, it's not that much of a deal:

Applicants in all services, except market-based services (i.e., services where licenses are issued through an auction), are strongly encouraged to file electronically via the Universal Licensing System (ULS). Applicants for Special Temporary Authority should apply on FCC Form 601 accompanied with the appropriate schedules. All applications for STA must also include an attachment justifying the need for an STA.

https://www.fcc.gov/applying-special-temporary-authority

The last time I applied it cost $70.00 and the authorization came out of the FCC field office in St. Louis.

Let me tell the OP why it is a good idea to file a 601. If a complainer hears you testing and reports it to the FCC, the FCC can check the database and tell the complainer that you are legal (not a pirate) and to go pound sand.

You will be issued a special call sign such as WY2XEZ, so you use that assigned call if you have to identify by voice or CW.


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WA4WAX
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« Reply #21 on: August 05, 2022, 05:56:19 PM »

Phil:

I did not see it as I have been in  pillar to post mode at work.

I like the idea.  Not a problem for 100 mW, but might be for 10 watts or more.

Thanks.

I see you found Janice Hendry (Now Janice Turner).  Nice woman.  I had some correspondence with her a few years back.  That ZW fabric is cool.
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« Reply #22 on: August 06, 2022, 12:07:46 PM »

to excite zenneck waves you need your radiator to match the complex-valued wavenumber (say the z-directed wavenumber, if z is perpendicular to the guiding surface) of such waves (as well as the real-valued wavenumber in the direction of propagation). Maybe your radiator does it, maybe it doesn't. And your metallic strip is most likely working as a perfect electric conductor stripline on a dielectric interface.

Think of a dielectric slab, you can't excite guided modes in the slab (modes that decay exponentially with distance outside of the slab) using propagating waves falling onto the slab from the outside. To couple to the guided modes you need special tricks (well-known and regularly used in the industry, a prism coupler, a finite grating, etc.).
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