Developing a small fuelless microwave thruster

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The EMdrive is a new type of thruster - recently invented by Roger Shawyer & Guido Fetta.
Unlike other propulsion systems which need to repel mass to produce thrust, the EMdrive can convert electrical energy into thrust directly.

There are endless uses for an EMDrive - in terrestric and in space applications.

A working EMdrive would start a revolution in spaceflight, enabling manned deep space exploration.

Several builds have been made worldwide (eg Chinese University, NASA), many show positive results. This topic is still quite new and needs a lot of research.

Most EMdrive builds work with frequencies around 2.4 GHz because a high power RF source for them can be made out of a microwave oven magnetron.
My attempt is is to build one which works with 24GHz, which reduces the form factor significantly and makes it possible to be used in small satellites.
A so small EMdrive could be flown to space for 20000$ on a pocketqube satellite.



The EMdrive is derived from a closed cylindrical microwave waveguide. The main difference is that one end is larger than the other. When RF is fed into the cavity and a resonance is achieved - according to Shawyer a thrust force will occur.


The first builds have not been summarized due to documentation cleanup process


EMDrive V3


The V3 is a silver cavity build, fed by a fully controllable RF source capable of beeing tuned between 22 and 26 GHz.

The reflected power can be measured in amplitude and phase.

First measurements with acoustic vibrations (by OOK modulation of the RF source) show a force near the designed target resonance frequency. The last experiment is reproducible and shows clear signals. Further tests must be performed to check for directivity of the force.

PS: Many many thanx to all the people who gave us very helpful hints how to improve the system. It has been an exciting ride for us until now, and we hope to provide a functional Baby-EMdrive soon

Special thanx go to TheTravellerEMD, Marvin Macportain, Keegan Reilly, Aurelio Chargb Ramos

EMDrive V4


This build was a complete integrated version which has been tested at the TU Dresden with Prof. Tajmar.

It should have been the flight version for our satellite in case the test would heve been more successful.

We had thermal issues during testing, with temperatures of the amplifier rising up to 90°C.

This led to a massive power derating in the amp.

We had to reduce power to keep the temperature low, so the final force was only slightly above the scale´s resolution.

Other effect like lorentz forces and thermal deformation had a significant pattern in the measure plot.
Tests have been made for 0°, 180° and 90°
Results are not for publilcation yet - we will perform further tests with version 5.

EMDrive V5


This is a development unit - derived from the V4 - which is intended to be tested at TU Dresden. It has some improvements to solve the problems that we had during testing of the V4.

It has an amplifier with better efficiency and is well thermally coupled to the casing for better heat management.

The new silver cavity geometry has an improved shape based on a proposal in Shawyer´s actual patent paper.

This shape will ensure that the pathlengths of the reflected waves on the longitudinal axis of the cavity is always kept to a multiple of lambda/2 of the resonance frequency.

  • New kind of thruster in development

    Paul Kocyla4 days ago 0 comments

    Just a quick update after a long time:

    The Dresden University will probably continue measurements on the BabyEMDrive thruster with an improved torsion scale. It can resolve 20nN.

    Please check out another promising technology for propellantless propulsion. I decided to share the development and tests on a Mach Effect Thruster:

  • Tests

    Paul Kocyla03/23/2017 at 21:20 1 comment

    In February the EMDrive V6 has been under test on the Technical University Dresden.

    As the pretest-board didn´t output the expected power, I made a quick redesign right before the test date.
    The output after a day in vacuum was around 500mW, that´s "only" 3dB less than the desired 1000mW. Not so bad for a simple 4-Layer board.
    Here is the board inside the scale box:
    I am not allowed to publish detailed results, but some information upfront:

    The thermal drift was much bigger than the possible thrust - anyway the force is depending on the frequency and seems - I say seems because that´ s only a quick observation - to be proportional to the amplitude of the resonance peaks.
    I was only able to spend two days in Dresden so the following long duration tests has been made without my presence.
    Possible forces are lower than 0.1µN, it´s still not 100% to say without eliminating the thermal drift, so we have to wait until this problem is solved.
    The thermal drift shows always in the same direction and disturbs the interesting signal into uncertainty. So thrust is not confirmed but also not busted yet.
    From my side - the Baby EMDrive is completed, unless an affordable amplifier with a significantly higher power appears.
    There is an IAC abstract from Prof. Tajmar submitted about this EMDrive with details available on the conference beeing held in September this year in Australia.
    Thanx to the many interesting discussions and suggestions.
    Special thanx go to Prof. Tajmar, Matthias Koessling and Marcel Weikert for making the measurements possible, and Dave, who boosted the project by financial help - hope we get some thrust out of it so we can send it to space.

  • Pre-Test smulations

    Paul Kocyla02/05/2017 at 16:18 1 comment

    Jamie (monomorphic) ran a simulation on the new EMDrive V5 cavity model. Great work and many thanx!
    He detected two modes - would correspond with my two resonance peaks on the real thing.

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  • New board ready for testing

    Paul Kocyla02/02/2017 at 22:42 3 comments

    The last board showed some power leak. The expected power could not be reached. It even degraded to 40mW - bad. Now I made a new board with better connectors and more careful routing which is ready for testing in Dresden.

    It is prepared for the highly sensitive scale and can deliver more than 200mW with 24GHz at 85°C (after cable- and connector lossed), so we should not get thermal issues this time. The ALU-Plate will be also fixed to the scale for better heat dissipation.The cavity is new (blogged about it before). It shows two clean resonance peaks at which we will test for thrust.
    Sweeps will also be made in case there are some other phenomena which may occur beside the two resonance frequencies.
    For an eventual integration into a satellite, the board can find and track the resonance peaks automatically.

    I´ll make a 360° video of the test preparation in Dresden (if allowed).

  • Measurement followup

    Paul Kocyla01/06/2017 at 06:07 1 comment

    Improvement in cavity resonance after simplifying the feed antenna:

    In the previous measurements I soldered a stub to the feed connector to reach lambda/4.
    In this configuration, this stub is missing. The feed pin is shorter than lambda/4 and its angle is the angle of the cone wall.
    There are only two peaks now, the first was also visible before, the second has a more narrow bandwidth and higher amplitude.

    Probably these peaks represent two different cavity excitement modes in this frequency range.

    We will track both of them in the next test session.

  • Cavity V5 measurements

    Paul Kocyla01/03/2017 at 21:19 5 comments

    Here is the setup:

    The EMDdrive V5 board is connected to the cavity´s feed antenna (lambda/4 stub).

    A shorted antenna is used as feedback port which is connected to a power sensor.

    First, I measured the amplifier´s performance by connecting it directly to the power sensor.
    Here are the results:

    At over 23.5 GHz the power is over 100mW - hmmmm it´s a 1000mW amplifier, so that´s not that good, the board is probably not perfectly designed, cables and connectors have losses. The sensor has a 20dB attenuator (compensated calculations for that) and a SMP to 2.92mm adapter, they will probably also cause some losses. So let´s say it´s around 150mW at the working frequency range.

    Now comes the interesting part: The feedback port is connected to the sensor, and frequency sweeps are performed. It´s basically a scalar network analysis.
    First, I left the cavity opened - this means the big endplate was not connected.
    Here is the result - flat, almost no feedback. That´s not surprising, should be like this:

    Look what happens when the big endplate is attached:

    We get three main peaks. Two strong and one weak - and some smaller artefacts.

    I assume the small disturbances are caused by the antennae destroying the optimal shape of the cavity.

    When you look at the power level, it seems that the feedback antenna is sucking all the power out off the cavity, not good, it was probably too long - but better starting off too long than too short. So I cut the feedback antenna shorter, from around 1.7 mm to 1mm (approximately). Here´s the result:

    That´s better. The feedback antenna now sucks 40mW instead of 100mW. That´s better, but still too much.

    Now I cut the antenna to the ground, it´s just a pin in the hole, but the result seems ok:

    Note that the V/div is now 20.0mV instead of 200mV, so it´s sucking just 10mW now.

    Probably some room for improvement here - let´s see, but that´s acceptable.

    BTW before the trolls cry again because of missing axis labels: The two last pictures have same labeling than the third last - I´m just too tired to insert them - have a newborn baby now and a full time job: X:FRQ sweep, Y: power 10mV <=> 1mW

  • EMDrive V5 and cavity prepared for testing

    Paul Kocyla01/02/2017 at 20:48 0 comments

    New EMDrive cavity and board prepared for measurements.
    A precise power sensor, cables (just assembled), adapters and attenuators are all rated for 26GHz.
    I will be able to tell soon exactly how much power the amp is delivering and will be able to measure the cavity properties and resonance condition.
    After these tests I will optimize the feed antenna for maximum power delivery. I will try dipole and loop.
    The cavity has two ports: One with the feed antenna at lambda/4 distance to the big plate and another with a short stub for feedback.

  • Equipment update

    Paul Kocyla12/22/2016 at 08:52 0 comments

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    New member in the lab family: A precision power measurement device.
    This device is capable of measung power qualitatively up to 26GHz.
    The funny thing is that although the design comes from 1975, it´ s still in use today and it still has its price. It´s the only thing you can buy to achieve the measuring precision for these frequencies which doesn´t have the price of a new familiy car - 40 years later. At the time of release it was different.
    Sensor head is the 8485a - was lucky to shot one on ebay for half the price they usually go.
    But now finally we get exact measurements for the EMDrive, which will help to optimize the overall design.
    The EMDrive itself will get its own power meter on board - in form of a small chip with less accuracy but good enough to do the job. But until then, this buddy will help to get qualitative results.

    The 26GHz equipment is quite expensive, for example a simple 2.92mm to SMP adapter costs over USD 70 - but it´s important to have the connectors and cables rated for the max. frequency, because in other cases the frequency response of the devices will have notches. Imperfections in the connectors lead to resonances and reflections inside the connectors, the connectors act like a weak cavity.

  • Cleaning up

    Paul Kocyla12/17/2016 at 18:54 0 comments

    The "Flying an EMDrive" project has been removed due to maintenance overhead.
    This doesn´t mean that the EMDrive will not fly - in fact we got a partnership which will make a launch available soon - stay tuned :)

    More details will come later - after we signed the contract

    The things changed a little bit now. We had a test session at TU Dresden with Prof. Tajmar and will establish a lasting partnership.

    The test results are not to be published yet due to an agreement, but what I can say is that the force was not high enough for a reasonable orbit test. The reasons were thermal issues in the high vacuum which caused the amplifier´s TX output power to degrade.
    I made a newdesign with a more efficient amp in an externall box which can be thermally cupled to the scale.

    Here´s the setup:

    I invested some of the funded money in a good used but affordable test equipment going up to 26GHz and will make a careful redesign for a next version V6.

    The paperwork for the satellite launch has been initiated, there´s a lot to do in 2017.

    I plan to do video blogging on the process. I am also expecting trolling as usual, so only constructive comments will be answered.

    The project page will be cleaned up as many of the first steps to get to the current state are not helpful anymore (learning fails).
    If you still need them then feel free to make a backup.

  • EMDrive V5

    Paul Kocyla11/27/2016 at 20:55 3 comments

    The EMDrive V5 board is assembled.
    The metal box can be attached to the scale body for better heat dissipation as we had heat issues during the testing in Dresden. There is also a more efficient amplifier on board which can delliver twice the power than the version V3.
    Now waiting for the new silver cavity to come.

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Enjoy this project?



hobbesalpha1 wrote 11/27/2016 at 15:59 point

Paul, are you going to include the sapphire plate to the big plate inside the vessel as the new patient shows?

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Paul Kocyla wrote 01/17/2017 at 10:02 point

As I read it the sapphire was only a support for the superconducting material. My endplate is just silver, as YBCO would not give any benefit at 24GHz. 

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bigattichouse wrote 11/18/2016 at 04:53 point

Is your python code on github? I'd like to try building a genetic algorithm to see if there might be better shape/Q values out there.

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Paul Kocyla wrote 11/18/2016 at 07:30 point

It´s written in C, but embedded in other code I used for an orbital simulator, so nothing publishable yet. When I fnd time, I´ll post the relevant functions or strip the code down.

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Justin Kenny wrote 10/09/2016 at 01:25 point

Probably been covered before, but why would an EM-drive be better than simply expelling photons (either RF or light) efficiently? That is, not making a "reactionless" thruster but just a normal photon thruster?

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Paul Kocyla wrote 10/09/2016 at 09:34 point

I´m not completely sure, but it looks like a photon only transfers a very small amount of energy during a reflection, so the more often it bounces, the more energy it can transfer. The simulation shows that the push-vector on the body accumulates into the direction of the small plate.
This would also explain why a higher Q factor of the cavity resulted in a higher thrust.
^^ my guess, no guarantee for correctness

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Justin Kenny wrote 10/09/2016 at 20:22 point

Did a little research, I think the EMDrive may end up being more efficient than photonic thrusters with optimization:

(From the "On the exhaust of electromagnetic drive" paper):

mean thrust of 91.2 μN with 16.9 W was recorded at 1932.6 MHz corresponding to the first TM211 mode in the tapered cavity having a quality factor of about 7320 and the mean thrust of 50.1 μN with 16.7 W was recorded at 1936.7 MHz corresponding to the second TM211 mode and the quality factor of about 18000 => 5.4uN/W

(From Wikipedia, Photonic Laser Thruster):

thrust of 3.5 mN ... the amplified laser power of the photonic laser thruster was greater than 500 kW, which was powered by a 500 W laser => 7uN/W

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hobbesalpha1 wrote 10/09/2016 at 00:51 point

Paul, now more than ever I think I have found out the mechanism as to how this works. I think what we have made is interestingly something we have made before, only this time we haven't used a ruby crystal to set everything up. If I am correct, we have something like a ruby laser. Everything that you can find in a laser we have in the EMdrive, a resonance chamber (in a laser it is a rod of ruby with mirrored ends, one with a small hole in it, the EMdrive is the same except everything goes through a vacuum) a pump source (in lasers, that is a light source that flashes at a particular rate, in the EMdrive it is the microwave source) , it even needs to be a certain length for the resonating chamber for a particular wavelenght of light, in our case we need a particular wavelenght to get force. What if the two concepts are exactly what we have been needing to look at, the partical escaping would be correctly idenified as a photon, and it's emittion would cause force to go in the opposite direction as one of the plates failed to act as a refective source.

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willemstaal wrote 10/18/2016 at 13:27 point

a smart observation.  i wonder why they not just use a maser in the experiments? 

One note: the EmDrive requires the use of spread-out waves (in order to
resonate), it would produce no thrust. So there is something different working here. I personally think that the presentation of the waves in the frustrum is essential. Thats why Guido Fetta choose a form that looks like the wave itself.  the em-drive needs a synchronised "clean" wave to work, not a distorted one. In the new patent  you find more information..

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hobbesalpha1 wrote 10/18/2016 at 13:51 point

In a way, the laser does the same. If anything, the one true difference is that any stray light rays from the ruby cylinder get discarded. Where as in the EMdrive, very little is being discarded because what ever might be leaving is very small in comparison to that which is staying. Also, I don't say the form of the EMdrive needs to change, quite the opposite infact. The new patient for the EMdrive actually made me quite happy with my theory. The shape is nessary as, unlike a laser, it would be almost impossible to focus the microwaves to the point where it could be useful with a regular cylinder. It might be also why a Maser might have an issue, but that is an interesting experiment for another time. It is possible that the next logical step up is the introduction of a maser or sets of masers.

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willemstaal wrote 10/19/2016 at 06:46 point

The interesting addition in the new patent is the use of a helix shaped antenna, to "guide" the rf wave into a specific form. There is also a phase locked loop attached to the system to sync the waves. Shawyer choosed carefully for mechanical parts that dont need much maintenance. A maser maybe dissipate too much heat in  the frustrum, unless they choose for a solid state one that works on lower temperatures. But nevertheless, if you can implement stimulated emmisions in a em-drive, this would be a huge improvement.. :)

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hobbesalpha1 wrote 10/20/2016 at 00:19 point

Another thing of note, and it caught my eye in the newest patent is the sapphire substrate. Information gleaned from patent figure 1 (4). This is of interest as sapphire is used in room temperature masers. It is possible that Shawyer is thinking one step ahead both in a mechanical sense and in a pure physics sense. Though there is one aspect I think we might also be overlooking and it is the reason I believe there is photons that are leaving the resonating chamber, no matter how we look at it a photon is still a small partical and I believe that there is quantum tunneling at work. The basis of this theory is we are pretty much ensuring that there is multiple impacts of photons aginst the inside of the chamber, almost the textbook case as the starting condition of quantum tunneling. Making photon escape not just a possibility, but a probable outcome.

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pete93003 wrote 09/04/2016 at 12:48 point

If what I hypothesize is correct there could be a electron shift in the outer shells  of the arriving adatoms based on the article out of ETH Zurich

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hobbesalpha1 wrote 09/05/2016 at 14:11 point

I once theorised the same, was hoping they would cover one of the ends with an insulator to test, but they are just hoping to get some forces out that they can see and I don't have the money or means to do the tests myself.

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pete93003 wrote 09/04/2016 at 12:31 point

Ok I have a challenge for your Em drive without in situ space testing. In Vacuum!

I have access to as the retired owner a Vacuum chamber capable of 10-7 torr with a ion beam sputtering source  that sputters metals and metal oxides at substrates. 

As these are very well defined optical structures with well  known packing densities and optical constants  any structural change to their arrival on substrates  could be determined post deposition, if a em drive was situated in a way to push the arriving adatoms away from their intended arrival pattern   ,Ie know thickness, uniformity across a given area and there change in optical constants both in Transmission and reflection of their polarized components, this could be easily measured against many 1000 of runs of optical filters with very narrow line frequency at multiple wavelenths.

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paul mccherry wrote 08/31/2016 at 09:29 point

Could you guys point me in the direction of reading material to understand the concepts of photon pairs, phases and other advanced concepts you are talking about in these comments. Unfortunately my physics education ends at conservation of momentum and I would dearly love to understand things more. I also think i need to brush up my maths.

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RandyKC wrote 08/17/2016 at 06:53 point

Beautiful model! 

Does your model look at paired photons out of phase with each other? Each bounce would reflect the photon in a different phase depending on the wavelength and the distance traveled before collision with a wall. Then they would need to pair with a photon of the opposite phase before being able to exit taking the momentum with them.  When the momentum of the pair exceeded the Q of the wall then it would punch through transferring the momentum. The question there would be "is it possible to change the angle of the sides of the nozzle's cone to maximize that pairing based on wavelength?"

If it was just photons punching through wouldn't they be detectable? It would be interesting if it was just the momentum that is escaping.  Maybe there are momentum particles like the Higgs and those are what is escaping. I understand that CERN is looking for something similar this next round. 

Your model does agree with your observations though.

Really looking forward to your posting the model.

  Are you sure? yes | no

Paul Kocyla wrote 08/17/2016 at 15:57 point

I didn´t implement the paired photon theory. While developing I just implemented the reflection including momentum transfer - which actually includes the conservation of momentum. I expected the EMDrive´s momentum to be zero after releasing photons, but it turns out that the momentum of the body builds up towards the small end - at least in the simulation with this simple model.

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wrote 06/30/2016 at 13:07 point

In german:

It seems a chinese team did this experiment with a battery as power supply, all contained on the measured platform, and then the effect vanishes.

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Paul Kocyla wrote 06/30/2016 at 13:55 point

I read the abstract - cause that´s the only part in English ;)
Their scale can measure 3mN and more. NASA Eagleworks measured 50µN thrust, that´s like one order of magniture smaller than the Chinese paper´s experiment test rig can resolve. I must check if they had similar power input.
It´s difficult to compare results when the testrig sensitivities vary so much.
Checked it: Nasa had less than 20W input and max. 90µN thrust

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hobbesalpha1 wrote 06/25/2016 at 23:23 point

Was there any measurements of the thickness of both the small round plate and large round plate?

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Paul Kocyla wrote 06/26/2016 at 05:06 point

There was no detailed information as far as I remember. They were talking about "interesting results".

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hobbesalpha1 wrote 06/26/2016 at 10:39 point

Reason why I ask is can we make the small round plate thinner? Doesn't have to be by a lot to test my new assumption. If it is a paired phased photon package that is the cause, decreasing the thickness of the smaller plate should increase thrust, as it provides less material to block the release of the paired phased photons.

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Paul Kocyla wrote 06/26/2016 at 10:54 point

Ok, I get what your idea is. My answer is I don´t know. So IF the paired photon theory is true, it would be good to know how far the photons propagate with 180° phase difference. If it´s forever or if they unpair after a few micrometers. I don´t know..

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RandyKC wrote 06/27/2016 at 19:02 point

If the Finnish paired photon theory is correct and if they unpair after a short time then the photons would be of different frequencies. Therefore they would only pair briefly as the frequency was changed.

If the photons unpaired wouldn't they then be detectable?

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hobbesalpha1 wrote 06/27/2016 at 22:36 point

Oddly enough, that was going to naturally be my next question. All it should take is something like a can of undeveloped film and putting the drive in a darkroom and turning it on. The undeveloped film should capture the photons as they exit and leave evidence of them, as long as everything that could give off light was covered.

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RandyKC wrote 06/16/2016 at 05:13 point

Have you read the latest theory presented by researchers from two universities in Finland on the operational theory of the EM drive?

Paired nonmagnetic photon pairs generate the thrust and according to their model the thrust is generated at the small end as you've found. My noob reading makes me think that they think it is similar to gravity. Could a interferometer be used, like they seem to imply, to detect these photon pairs?

Amazing theory. I hope they are right. If it's understood it can be made more efficient. 

  Are you sure? yes | no

Paul Kocyla wrote 06/16/2016 at 05:36 point

I read it. They say that the photons which are paired are phase shiftet by 180° and so don´t interact with the walls of the cavity. They seem vanished but in fact they leave the cavity and take momentum with them - which creates the thrust.
But I don´t understand it in detail.

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RandyKC wrote 06/16/2016 at 06:11 point

Would a silicon crystal photovoltaic detect them?

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Paul Kocyla wrote 06/16/2016 at 06:17 point

I made some measurements with the cavity behind the interferometer beam, but the result was not clear.
I ordered a new polished silver cavity for the flight model, it will have a higher Q. Thanx for the info, I´ll perform the interferometer test again when it´s assembled.

  Are you sure? yes | no

Paul Kocyla wrote 06/16/2016 at 07:23 point

I really don´t know if they can be detected at all. I remember having read somewhere that they are very hard to detect because they don´t interact on electromagnetical level with matter anymore when paired. But "very hard" is not impossible. I need to look for more infos online.

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Paul Kocyla wrote 06/16/2016 at 20:00 point

Hey Randy. I´ll try to code a simulator for the paired photon theory during weekend. Waiting for parts for the #EMPQ satellite anyway, so I can use the time to do that. It will be a simpliied 2D version - just an experimental quick try to see what happens if you throw photons around a tapered cone and superimpose their phase. I won´t publish it until it´s ready. I´ll release the software if it shows interesting behaviour so everyone can try their EMDrive shape with it. The model will be not exact, because it´s 2D and it´s quantized to pixel-leve.l. But it might be plausible. So I just treat is as a "toy" but hey let´s see what´s the outcome.

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RandyKC wrote 06/17/2016 at 05:04 point

I know you're crazy busy. Thanks for talking. This is such a cool project. Wish I could "like-like" it:-)

I wonder if there are ways to simplify the test. 

If the Finnish model is right, then the photon pairs only escape when they exceed the Q(is that right?) of the small end. If the photon pair is low enough energy they would bounce off the higher Q silver mirror. Too high and they will pass through. So we won't know what percentage could be detectable and we'll only detect the photon-pairs for a relative narrow band of energy. We also don't know how long it takes for a photon-pair to form.

Is it possible to just measure mirror deflection with the drive on and with it off?

Would thrust be more directional if the material at the larger end was a higher Q value?

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hobbesalpha1 wrote 06/18/2016 at 11:30 point

Oddly enough I was toying with that same idea myself. Entirely possible as copper is of a lower Q factor then silver, but still higher enough that it might be able to work well enough for resonance.

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Paul Kocyla wrote 06/18/2016 at 15:10 point

 I think the overall Q factor of the cavity will be lowered when changing the endplate to a material with lower conductivity. The material itself has no Q factor. Q factor is reciproc proportional to the bandwidth of the resonator and has no dimension.

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Paul Kocyla wrote 06/24/2016 at 07:41 point

Hey Randy: Actually it was not meant as a sarcastic joke with writing the simulator :) That software is really on the todo-list. I blew the dust from my OpenGL sources and will do a 3D-Simulation for the paired photons.

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RandyKC wrote 06/25/2016 at 17:55 point

I'm having trouble understanding where the photons come from. Is it the interference of the microwaves or the interaction of the microwaves with the gas in the chamber (eg. Oxygen)?

Some papers talk about microwave frequency photons being very weak. 

They all point out to me how much more I need to read to learn more about microwaves.

BTW HAD, the reply structure is too shallow.

  Are you sure? yes | no

Paul Kocyla wrote 06/25/2016 at 18:49 point

Reply structure: Definitely crappy :-D
Waves and photons are the same thing. It´s the particle-wave duality. The higher the Q factor of the cavity is, the more often the photons can bounce around, therefore more photons are inside the cavity - therefore the probability arises that two photons pair with 180° phase difference and leave the cavity (assuming the finnish theory is true).
Microwave photons are weak compared to light , because Energy=h*frequency ( h is planck constant) Light has a much higher frequency than the microwaves in the cavity.

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RandyKC wrote 06/25/2016 at 20:15 point

Arrgh, I "knew" that but never made the connection. Ok, then why would this only work with microwaves? Does something to do with the higher energy state of visible light photons make it harder for them to pair?

  Are you sure? yes | no

Paul Kocyla wrote 06/25/2016 at 20:41 point

I don´t know. Maybe the conical shape of the cavity is advantagous for the photons to take the same path after a few reflections. I think I´ll have to spend some time to write that simulator. Maybe the answer will come that way.

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Monomorphic wrote 06/14/2016 at 00:31 point

Hey Paul. Can confirm that "IslandPlaya" is a known troll from /r/emdrive. 

Other DIY builders have started a new subreddit here:

Please feel free to join and submit. We hope to see you there! I'll make sure to drop by and visit you here from time-to-time. 

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Paul Kocyla wrote 06/14/2016 at 15:36 point

Thanx, i´ll do it.

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Paul Kocyla wrote 06/12/2016 at 14:33 point

Troll alert for "IslandPlaya". He appeared here as an already known troll from reddit to spread his crap. Please ignore him, he´s not here for discussion.

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IslandPlaya wrote 06/12/2016 at 11:31 point

This paper I believe describes the best experiment yet on the em drive anomalous force. It finds ZERO force. Paul, please continue to improve your experiments by all means, but can I suggest you withdraw requests for donations of cash from others to fund your hobby. It appears to me to be less than totally honest, which I'm sure is not your intention. Thank you.

EDIT: I removed the accidental dupe post.

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Paul Kocyla wrote 06/12/2016 at 13:57 point

Please don´t post the same comment twice. And may I suggest that you introduce yourself first before throwing comments at me. It´s getting annoying of waving away trolls. BTW this is not the right platform to discuss your problems with sex.

Addidtional information to others: This guy has been classified as a troll already on reddit.

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IslandPlaya wrote 06/12/2016 at 14:24 point

My name is IslandPlaya. I have been following the saga of the em drive since Shawyer's appearance in New Scientist magazine many years ago. I am (amongst other things) an investigative journalist.
Can you please share your opinion of the paper I posted and how you are going to improve your equipment to better it. A suggestion would be for you to invest in a graph-axis-labeling machine to start with.
Your BTW is a bit strange I think.

Thank you.

EDIT: If you prefer we can continue this conversation at if you prefer that platform.

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Paul Kocyla wrote 06/12/2016 at 14:30 point

Axis labels described in the logs - so far for "investigative journalist".
Maybe a valuable information for the others as the paper is out there: This paper claims that there is no force WITHIN THE RESOLUTION of the setup tadaaaa nothing new my journalist - it has no specific meaning so far. There are other papers with positive results. That´s why it´s  still controversial.
Don´t play clever with me, you are not a journalist, you are not a scientist and you are not an engineer, right? Not hard to guess.

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pomeziri wrote 06/12/2016 at 14:13 point

This would be a more complete bibliography:

Second generation EmDrive propulsion applied to SSTO
launcher and interstellar probe by Mr. Shawyer 


Numerical and Experimental Results for a Novel Propulsion
Technology Requiring no On-Board Propellant 


Youtube video by Mr. Berca “EmDrive Success, I have thrust
!!!” ().

Microwave Energy Injection into a Conical Frustum by Dave


Direct Thrust Measurements of an EMDrive and Evaluation of
Possible Side-Effects.


EmDrive: Propellantless Electric Propulsion 


Net thrust measurement of propellantless microwave  thrusters*

Later Modified by Thrust Measurement of an Independent
Microwave ThrusterPropulsion Device with Three-Wire Torsion Pendulum Thrust
Measurement System 


Anomalous Thrust Production from an RF Test Device


My understanding is several other independent researchers
are claiming positive results, but have yet to revealed their final reports.



Also, NASA Eagleworks, based on their last communication,
has continued to claim positive results 


However, NASA continues to await publication of their peer reviewed materials. (

A private company, Cannae, just recently completed a successful demonstration of their superconducting EmDrive-like cavity. 


All the experiments, however, are still very controversial
and better experiments will be needed to convince the scientific community and rule out other explanations for the alleged "thrust". Thermal and electromagnetic spurious effects have not been totally ruled out entirely.

Hopefully, Paul Kocyla and his team will help to validate or invalidate the
EmDrive. Putting the EmDrive into orbit is probably the only way to demonstrate
a definitive proof one way or another and a Cubsat is likely the only economical way to do that in the short term. 

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Paul Kocyla wrote 06/12/2016 at 15:18 point

Thanx for summing up the information to the point, great!
We will try our best to make the satellite launch happen. And no matter what results we get, it will be an exciting time.
The satellite is designed to be interesting for radio amateurs and those who want to become one because of its special transmitting mode. We are writing "visually" a text into the frequency spectrum which can be received with a simple antenna and an USB stick. As no EMDrive has been in space yet it could be an exciting adventure for everyone to receive and track it.

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Jamie Sibley wrote 06/10/2016 at 04:53 point

I have taken a look at your latest data from June 1st and 2nd and I think I found some meaning full data buried in there.  I wrote a quick c# program to confirm my suspicions.

1. First I took the data and calculated the angular rate for each line.
2. Then I took a 20 minute moving average of the angular rate because it was so noisy.
3. Then I graphed both runs on top of each other with frequency on the X axis and magnitude on the Y.  I also included power and phase in the graphing.  

What I found is that when the power is at its peak value, the phase is near its median value and the two graphs of angular rate are opposite and of equal magnitude !

The frequency is near 23.250 GHz when this occurs.

On the included graph, the Y-axis has been shifted and scaled for the power and phase.  

The equal and opposite angular rates are very strong evidence that your thruster is really working.

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Paul Kocyla wrote 06/10/2016 at 05:38 point

Wow! Thank you very much for your effort, these are excellent news :)

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RandyKC wrote 06/04/2016 at 20:26 point

So, what I see from the combined graph is a green line that I assume means angular changes in the unit during test and the yellow line is the thrust generated. The reason I ask is that the reports I hear about through the media seem to imply the thrust generated is very small and almost within measurement error. Your results seem to indicate a strong directional thrust with no measureable angular component that would seem to be proof this isn't due to parasitic forces. Is my interpretation correct?

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Paul Kocyla wrote 06/05/2016 at 06:38 point

The yellow graph is the frequency of the transmitter and the green line is the angular displacement.
I made a viewer so you can change the yellow graph to either frequency, phase, power, temperature or PA current.
The test data is saved as plain text. Take a look at the repository link.
During these tests, I sweep the transmitter frequency between 22,5 GHz and 25.5 GHz over several hours and measure the displacement at the same time. Around 24 GHZ, which is the designed frequency for the cavity, the displacement is strongest, and it changes directiion when the cavity is turned 180°.
I could assume that the temperature change of the cavity plays a parasitic role, but in fact id doesn´t. The temperature is rising constantly with rising frequency, but the peak first gets stronger and then weaker during the period. 
It´s a strong implication for me that the EMDrive works.
You can check the data with the viewer if you like. The latest files are june01sr.emd and june02br.emd

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hobbesalpha1 wrote 04/30/2016 at 23:18 point

Great work! Since there seems to be a method set up now, could we maybe try modifying the vessel design just a little bit more, like maybe changing the most of the vessel to ceramic, but leaving the small plate as silver?

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electronnja wrote 05/10/2016 at 04:41 point

Just out of curiosity, why ceramic?

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hobbesalpha1 wrote 05/11/2016 at 02:09 point

Well, microwave vessels can be made from ceramic, my thought is since a dialectric has proven to not hamper the possible creation of force, and everything being equal, that a ceramic vessel should be of similar ability. If there is a change, my thought is that it could be a direct result of vessel change. However if there is no change, then it points to a new reality, possibly even lighter drives.

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Paul Kocyla wrote 05/12/2016 at 05:41 point

According to the theory, the thrust is linearly proportional to the Q factor of the cavity.
When the cavity is made of non-conductive ceramic, the Q-factor will be a few thousand times smaller - resulting in basically no thrust at all.
What I can play with are different dielectrics inside.

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hobbesalpha1 wrote 05/15/2016 at 13:59 point

Any chance you could try dielectrics on the outside as well? Or was that the results you got from 4/22/2016 posting?

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Paul Kocyla wrote 05/15/2016 at 15:48 point

Putting it outside would theoretically have no effect, because the wave penetrates the conductive inside material in some micrometer depth -> skin effect

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hobbesalpha1 wrote 05/28/2016 at 17:40 point

The other reason for the dielectric on the outside is to test one of the main draws of this type of drive. To see if the drive can cause force when inside a vehicle or even inside a box. If the drive is in an enclosed box, it should still move the box as the force is due to what is happening inside the vessel, not outside. It should be a form fitted box around the vessel only. If a success, it means that it validates the main tenet of the emdrive. If it fails, it might give us a zero drive, which is just as important as it allows for even more effective emdrives.

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Horst Falting wrote 06/11/2016 at 20:08 point

What we could try, and I would like to help you organize a crowd fund for this,  is

coating the inner walls of the emdrive with YBaCuO and than cool the EMDrive with liquid nitrogen.

Would you like to do this?

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Paul Kocyla wrote 06/12/2016 at 08:06 point

@Horst: In a former log I mentioned to make a superconductive cavity. I have the materials here, chemicals, oven, dewars.
Due to time issues I suspend the superconductive build until the satellite is ready.

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Shpoople wrote 04/26/2016 at 22:48 point

It's so cool to see people that are much smarter than me running serious experiments on things that seem to violate the law of conservation of momentum, it shows that people are willing to try new ideas.

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Xark wrote 04/20/2016 at 22:33 point

Hello, I found this recent article regarding EM drive physics and I thought people interested in this project might find it interesting.

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Paul Kocyla wrote 04/21/2016 at 07:09 point

Thanx. Interesting article.

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mr-sunderland wrote 04/17/2016 at 23:27 point

Have you considered lining the cavity with bismuth?

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