To stop any shifting, especially as I plan to ship finished EMDrives all over the planet, the single 1/4 wave stub antenna was replaced by 3 x 1/4 wave stub antennas that are joined at the centre and attached to the centre of 3 Rf connectors fitted into the side walls.Trust the attached crude drawing makes it clear how I intend to excite TE013 mode and do so in a way to introduce min phase distortion into the internal resonant standing wave by the excitation antenna.
Quote from: TheTraveller on 07/09/2015 05:20 amTo stop any shifting, especially as I plan to ship finished EMDrives all over the planet, the single 1/4 wave stub antenna was replaced by 3 x 1/4 wave stub antennas that are joined at the centre and attached to the centre of 3 Rf connectors fitted into the side walls.Trust the attached crude drawing makes it clear how I intend to excite TE013 mode and do so in a way to introduce min phase distortion into the internal resonant standing wave by the excitation antenna.I understand you will connect your RF amp to those three 1/4 wave stub antennas. But after that, does that also allow your design to connect 3 separated RF amps to multiply the input power x3? If so, how to couple those? In read a few pages ago that some dual magnetron geometries can automatically tune themselves. What about multiple solid-state WiFi amps? Do we need some external controller or would they naturally lock their frequencies and phases together?
Maybe we could upvote and get Adam Savage's, co-host of MythBusters, attention. It would be a dream to have this myth busted (or confirmed!). http://www.reddit.com/r/IAmA/comments/3cfqzf/z/csvcjt3Outer Space or Bust!
The Chinese may have figured out how to make a cavity with a Q of 117,500 using flat end plates.As per the attachment they build in a short section, at each end of the tapered wave guide, of constant diameter circular waveguide that allows the spherical waves in the tapered portion of the cavity to transition from/to a planar wave that will generate no phase distortion as it bounces off the flat end plate.Very clever.The drawings also show how they do impedance matching.See attachment.I now know my 100,000 Q goal is obtainable. Yea!
Quote from: TheTraveller on 07/09/2015 07:54 amThe Chinese may have figured out how to make a cavity with a Q of 117,500 using flat end plates.As per the attachment they build in a short section, at each end of the tapered wave guide, of constant diameter circular waveguide that allows the spherical waves in the tapered portion of the cavity to transition from/to a planar wave that will generate no phase distortion as it bounces off the flat end plate.Very clever.The drawings also show how they do impedance matching.See attachment.I now know my 100,000 Q goal is obtainable. Yea!If you draw a horizontal axis through the middle of the waveguide in the picture you show, what does the waveguide opening into the cavity on the plane perpendicular to that axis look like?In other words, what does the other view look like?It would be nice if we could guesstimate what the waveguide opening aspect ratio is, compared to the lateral cavity dimensions
Sooooo..... the Poynting vector has a DC offset eh? Who would've thought that! LOL!http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=1041397This means E and H should have a DC component as well, which means there are probably DC circulating currents around the frustum as it's charging.At least that is how I would interpret these extrapolations and the uni-directional poynting vector.Todd
...More info is in the paper, which is in Chinese. Attached.I don't think the drawing is dimensionally correct.
Quote from: TheTraveller on 07/09/2015 12:00 pm...More info is in the paper, which is in Chinese. Attached.I don't think the drawing is dimensionally correct.Please let us know if you guesstimate what the waveguide opening dimensions used by Prof Yang are.QUESTION: are you planning to use a waveguide feed into the cavity in your experiment, as used by Prof. Yang?
How would you suggest building a rotational measuring system?If we were to build it with a few 1 inch peaces of wood as a rotational system which bearing would be fitting?It would have to take the weight of the "em drive" or whatever and weight of the wood as an axial force and still have less then say 20 micro Newtons of tangential friction resistance.
Quote from: Rodal on 07/09/2015 12:58 pmQuote from: TheTraveller on 07/09/2015 12:00 pm...More info is in the paper, which is in Chinese. Attached.I don't think the drawing is dimensionally correct.Please let us know if you guesstimate what the waveguide opening dimensions used by Prof Yang are.QUESTION: are you planning to use a waveguide feed into the cavity in your experiment, as used by Prof. Yang?Will be using a 100W narrow band Rf amp feeding the internal frustum spherical antenna array via 3 coax cables & connectors.
@SeeshellsWhy not use an interferometer to measure the displacement? Too much noise?http://www.instructables.com/id/Desktop-Michelson-Morely-Interferometer/
Quote from: TheTraveller on 07/09/2015 01:03 pmQuote from: Rodal on 07/09/2015 12:58 pmQuote from: TheTraveller on 07/09/2015 12:00 pm...More info is in the paper, which is in Chinese. Attached.I don't think the drawing is dimensionally correct.Please let us know if you guesstimate what the waveguide opening dimensions used by Prof Yang are.QUESTION: are you planning to use a waveguide feed into the cavity in your experiment, as used by Prof. Yang?Will be using a 100W narrow band Rf amp feeding the internal frustum spherical antenna array via 3 coax cables & connectors.Where in the frustum will your spherical antenna be located? (is it going to be located in the longitudinal axis of axisymmetry of the cone?, is it going to be located near the big base? near the small base?
Further info on the antenna arrangement I'll be using on my 2.45GHz version of the Flight Thruster.As the EM waves in a cavity with spherical end plates are spherical, the antenna also needs to be spherical as per the sidewall insertion point curve of the EM wave at that point.I could have used a single stub 1/4 wave antenna curved to match the spherical EM wave shape but I had reservations that the end point of a single 1/4 wave stub inside the cavity may shift over time.To stop any shifting, especially as I plan to ship finished EMDrives all over the planet, the single 1/4 wave stub antenna was replaced by 3 x 1/4 wave stub antennas that are joined at the centre and attached to the centre of 3 Rf connectors fitted into the side walls.Trust the attached crude drawing makes it clear how I intend to excite TE013 mode and do so in a way to introduce min phase distortion into the internal resonant standing wave by the excitation antenna.
Quote from: TheTraveller on 07/09/2015 05:20 amFurther info on the antenna arrangement I'll be using on my 2.45GHz version of the Flight Thruster.As the EM waves in a cavity with spherical end plates are spherical, the antenna also needs to be spherical as per the sidewall insertion point curve of the EM wave at that point.I could have used a single stub 1/4 wave antenna curved to match the spherical EM wave shape but I had reservations that the end point of a single 1/4 wave stub inside the cavity may shift over time.To stop any shifting, especially as I plan to ship finished EMDrives all over the planet, the single 1/4 wave stub antenna was replaced by 3 x 1/4 wave stub antennas that are joined at the centre and attached to the centre of 3 Rf connectors fitted into the side walls.Trust the attached crude drawing makes it clear how I intend to excite TE013 mode and do so in a way to introduce min phase distortion into the internal resonant standing wave by the excitation antenna.I would hope you take in consideration the phases of your antennas and the distance from each other, you wouldn't want them to cause standing wave attenuations with each other canceling out a good idea.
Quote from: SeeShells on 07/09/2015 01:43 pmQuote from: TheTraveller on 07/09/2015 05:20 amFurther info on the antenna arrangement I'll be using on my 2.45GHz version of the Flight Thruster.As the EM waves in a cavity with spherical end plates are spherical, the antenna also needs to be spherical as per the sidewall insertion point curve of the EM wave at that point.I could have used a single stub 1/4 wave antenna curved to match the spherical EM wave shape but I had reservations that the end point of a single 1/4 wave stub inside the cavity may shift over time.To stop any shifting, especially as I plan to ship finished EMDrives all over the planet, the single 1/4 wave stub antenna was replaced by 3 x 1/4 wave stub antennas that are joined at the centre and attached to the centre of 3 Rf connectors fitted into the side walls.Trust the attached crude drawing makes it clear how I intend to excite TE013 mode and do so in a way to introduce min phase distortion into the internal resonant standing wave by the excitation antenna.I would hope you take in consideration the phases of your antennas and the distance from each other, you wouldn't want them to cause standing wave attenuations with each other canceling out a good idea.Shell, there is also the issue that in the drawing, the assumption is made that the wave-patterns in the longitudinal direction are sinusoidal harmonic with equidistant nodal points. This is true for a cylindrical waveguide but it is not true for a conical waveguide. With a conical waveguide the wave-patterns in the longitudinal direction are not sinusoidal harmonic: the nodes are not equidistant. How different from equidistant the nodes are depends on the mode(s) being excited and their participation