Further steps

The magnetic levitation rig is not forgotten:

We will build a new levitator from scratch, with a strong electromagnet, an analog feedback loop for stability and a precise platform.

It will be designed that it can fit into our small vacuum chamber.

But this will take much time, so in the meantime we will perform experiments with a swimming platform.

The first results will be available probably next week.

Further in the future, the oscillator will be replaced by a custom build with 500mW

Discussions

Blaine wrote 06/30/2015 at 15:12

How goes the EmDrive experiments? Sorry, but curiosity and enthusiasm got the best of me and I had to ask.

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Paul Kocyla wrote 07/01/2015 at 06:38

I am designing a digitally controlled RF generator with feedback antenna right now. It will take some time to get it to work, as a lot of firmware is required and the cavity has to be modified (or a new one has to be made)

The swimming platform is almost ready, so we hope to see new results with the actual setup soon.

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David wrote 06/22/2015 at 15:03

There are a lot of cheap 5W 5.8GHz amplifiers for sale on the internet, as well as up to 800mW 5.8 GHz AV transmitters. These have multiple channels. Could they be used as a microwave source for a test EMDrive?

Jrodal, would you be able to calculate the optimal cavity dimensions and antenna geometry and placement for this wavelength? McCulloch recommends curved endplates as well I see: https://www.blogger.com/comment.g?blogID=4637778157419388168&postID=2382778000598121830

Maybe with this info, someone with a machine shop can also make a test setup.

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jrodal wrote 06/21/2015 at 22:05

@movax, I run a number of calculations based on your Baby EM Drive geometry you may be interested in. My (~45 pages long) report is posted as an attachment to my message on the NASA SpaceFlight Forum EM Drive thread 3: http://forum.nasaspaceflight.com/index.php?topic=37642.msg1392223#msg1392223

Best regards

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Paul Kocyla wrote 06/23/2015 at 08:10

Great work! I´ll check it out.

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TheTravellerEMD wrote 06/21/2015 at 04:21

Even with 500mWs and an optimistic Q of 25k, the thrust is at best 50uN or the weight of 1.67 snowflakes. That is assuming the cavity is impedance matched to the generator, your antenna is properly positioned and of the proper length to excite your chosen mode.

BTW what is the mode you are exciting? I used TE013 as there is length resonance there.

Are you measuring your VSWR to ensure your cavity is impedance matched as if not, all or most of your Rf may be reflecting back to the generator and produce little or no thrust.

Shawyer has stated he doesn't know of any successful EMDrive build that didn't have the ability to tune the cavity impedance to match that of the Rf generator.

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Paul Kocyla wrote 06/21/2015 at 07:17

Did you publish your results?

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TheTravellerEMD wrote 06/21/2015 at 08:21

I'm currently in bed, recovering from major surgery. Should start on my build in 4 or so weeks.

My latest design spreadsheet can be found here, along with pictures of how Shawyer did his thrust measurements. The overhead spring method is the simplest build.

http://emdrive.wiki/Useful_EMDrive_Design_and_Test_Tools

That said my comments are still valid. Getting a good antenna design and location that causes impenance match, desired mode excitation and optimal internal placement to sync with the internal standing wave is not easy. In fact it is the hardest thing to do and what causes many EMDrive builds to fail. Roger Shawyer told me he didnt know of any successful EMDrive build that didn't have the ability to manually tune for lowest VSWR or best cavity impedance match to Rf gen impedance.

Best of luck with the new build.

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Paul Kocyla wrote 06/21/2015 at 16:14

We can´t measure the VSWR due to lack of equipment for that high frequency. Our cavity is based on the Chinese paper, scaled to match our frequency.
Our new design will have an integrated transceiver IC to measure the power exactly for tuning the cavity properly.

This one is a firstie. We just want get some implication that it works.

Thanx for your comments and best wishes for your recovery.

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TheTravellerEMD wrote 06/21/2015 at 16:31

The Chinese paper? They never disclosed all 3 dimensions as far as I know.

What mode are you exciting? Would guess TE013?

You will need that new chip to give you feedback as you manually tune your cavity to match Rf gen impedance. Might suggest 1 or better still 3 screws on the opposite cavity side to the antenna feed. You need every mW you can get inside the cavity.

Heath is recovering. Thanks. Hate to be restricted to bed. Too much to do.

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Paul Kocyla wrote 06/21/2015 at 17:08

We collected all information we could get. Some people reversed engineered the dimensions from published piictures - we don´t even know which picture belonged to which experiment.
As our goal was to just replicate a 2.4 GHz drive we didn´t care about calculation, we just wanted to build it and eventually see some thrust.
Then we decided to make the small version, just as a blind shot, and we used the dimensions we got to scale them down to our 24GHz choice. So the mode will be TE013 as you said - but naive as we are, we didn´t know it.
Anyway it´s an opportunity for us to learn more about microwaves. I come from EE and CS, Jo comes from machine engineering, so there´s still som theory to learn for us. Is your tool open or top secret project related? I guess it would be really helpful for developers who are new in that area.

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TheTravellerEMD wrote 06/22/2015 at 00:31

The spreadsheet is here along with pictures of the various ways Roger Shawyer used to measure the generared force:

http://emdrive.wiki/Useful_EMDrive_Design_and_Test_Tools

You can contact me via private PM on NSF to get my email. Will then help you to understand the spreadsheet.

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Paul Kocyla wrote 06/23/2015 at 08:13

Thanx a lot - you did an amazing work. I´ll check the spreadsheet out and will contact you.
Currently I am building the swimming platform, let´s see if it shows some positive results.

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jmossman wrote 06/20/2015 at 20:06

Best of luck on the new design. May I suggest flash storage for telemetry/logging? Storing not just hi-resolution gyro but also hi-resolution control loop data would likely aid experiment analysis.

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Paul Kocyla wrote 06/21/2015 at 07:45

Thank you. The swimming platform will track two LED markers with at least 30fps.
It should be more accurate than the gyro I was using before.
We´ll provide the high resolution data for download too.

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Torsion Test 4 (inversed)

Swimming Platform

Discussions

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