Hello again, hope I am not bothering, but are you referring to this when you say fixed plate cavity
 ?

No, it´s the new one, just without the tuning screw. Instead, there is a metal plate at the end. I took a picture, but somehow can´t post it here, drag and drop doesnt do it.

You mean this one? Didn't see the big plate side, is it like the one with the adjustable screw where the big plate is covered? Also try pasting the link :)

Yes, it´s this one. Still can´t paste the pic. Maybe it´s my browser.

 i just found out how to paste images: just copy  the link into the reply field..  And if you want to use a picture on your computer: stash it first on a imageserver like tinypic or similar.

Paul. 

When the freq hits frustum resonance, initially the empty cavity will appear to have 0 impedance (act like a short, reflecting back all Rf) and then over 5 TCs fill to max capacity. 1 x TC seconds = (2 Qloaded) / (2 Pi freq). Should add that after the frustum is filled and the Rf is turned off, the frustum's energy will flow back to the Rf generator (taking 5 TCs) and become heat.

So even without measuring Force generation, you should be able to do a sort of rtn loss scan to search for and map out frustum resonances by just monitoring for current spikes as the frustum absorbs Rf energy. If you can measure reflected power can then get VSWR & maybe tune for best VSWR.

You should be doing this frustum resonant freq mapping and lowest VSWR tuning 1st, before looking for Force generation. Why? Cause if you don't get the 1st 2 steps right, you may find it hard to get Force generation.

Thanx a lot. I´ll look if i can implement that. I´ll have to do a firmware change on the RF board to get this data fast enough. Currently I can just send and receive via 9600bps UART. I put a stub antenna near the connector to the RF cable, so maybe I can measure VSWR through it indirectly.

Can you measure reflected and forward power?

I can measure the current to the PA and (indirectly) the leaking power from the power amplifier output (via a stub antenna) near to the connector. The current is the yellow graph in the charts, the RX power is the blue graph (not sure about the polarity and absolute value, these are only ADC values)

Paul. 

You need 100% to get access to a VNA and run a S11 rtn loss sweep across your Rf gens freq range. From that you should get resonant freqs and rtn loss dBs or VSWR. To get Force you need to KNOW you have BOTH resonance and low VSWR at the resonant freq, otherwise you will be chasing ghosts.

As you can vary Freq, would suggest you consider building in a forward & reflected Rf measurement circuit. Plenty of examples on the net. Then you can tune the freq for highest rtn loss dBs / lowest VSWR and measure your frustum Q, VSWR, forward & reflected Rf power in real time.

Then getting a good Force generation should be relatively easy.

Any indication as to where the thrust is vectored? Is it to the smaller end or larger?

I don´t know. Although I can see in which direction the interference rings are going, it´s hard to determine in which direction the rig goes, without having a reference.

I can try to hold a magnet to the rig and attract it into a defined direction. Then I´d see in which direction the rings are going. This might work.

Reason why I ask is if you can determine if the force is forward or if the force is backward really helps. If the force diagrams and the original theory is to be believed. It doesn't matter the drive configuration, it should always be pointing forward, or if you fitted the drive on a track it would be moving with the small plate being the front. If instead it was moving backwards, or with the large plate being the front, I believe at that point you have discovered something akin to an inverse drive. That would be almost far better then a zero drive in learning how this thing actually ticks.

Yes. For the next tests I will check in which direction the platform moves according to the interferometer rings, so we´ll know which endplate is leading. Then I´ll make tests with just the cavity turned around, and we´ll see if the forces inverses too.

Thanx for the accurate explanation. I´ll try to use the existing hardware to make the RF measurements you propose.
In future, I´ll make another board capable of doing this. The problem is, that the 24GHz range is much harder to handle than lower frequencies. I´ll have to use specialized ICs , a discrete build is imho impossible in that band.

Finding someone with a VNA would be great, maybe I can ask at the university, we got a good HF institute here.

i'm curious about what happen if 24 magnets turn around the cone at 1GHZ ...

They will become plasma, but probably they will desintegrate within nanoseconds :-D

Paul your magnets are too strong
very small coils and alternative electricity should mimic it without destroy
can you make a small module in openscad to give peoples easy stl of cones for any wavelength of interest in EM* ?
you can't test anything that can pop in mind of anyone ;)

Yes, we´ll post the OpenScad files for the cavity - actually it´s almost a one-liner, cause the cylinder procedure expects two radius parameters anyway.

Paul i asked a module not 1 cone.scad ;)

i know openscad is simple

i can only use it : i'm too handicapped to correctly use a mouse or touchscreen

but i don't know the math to make correct size for any resonnator cone for any wavelength that have an interest in EM*

it should take you less than 3 hours ...

Paul, i have a question about the densities of the materials you use:

copper has a density of 0.324  lb/in3 (the material Shawyer uses copper for his cavity

silver has a density of  0.379   lb/in3 

Does this have a affect on the overall measurements?

I don´t think so. But the conductivity is important, because it has direct effect on the Q factor. Silver has a slightly better conductivity than copper, so given two identical cavities, one of silver one of copper, the silver one would have a better Q factor.

So a cavity of thermal pyrolytic graphite would be even better! and a less weight too!

Don´t mix electrical conductivity with thermal conductivity. Pyrolytic graphite is a poor conductor.

not if you give it a galvanic coat of of silver..

Hey Paul, I've been wondering - what do you predict the maximum thrust from this scale version of Shawyer's EMdrive will be (is it 100g)? Also, what is the scale of your device compared to Shawyer's original thruster?

Scale is about 1:10

According the thrust: Shawyer´s thrust force (fed with several hundred watts) was 0.2-1g.
We are feeding with max.500mW and expect something in the µg range. The forces are very tiny, that´s the reson why we build an interferometer arund it.
Nevertheless, even these tiny forces have a big value in space - because you don´t need fuel, you can run the thruster theoretically forever as long as there is electrical energy available (sun, nuclear)

Thanks, that is so cool! I can't tell you how excited I am to see the results (or lack thereof). If you confirm thrust, do you have any other experiments in mind? The effect of thrust on another object (a feather, for example), placing the device on a rail to see if it can move itself? etc.   

These kinds of ideas only brings up another question, according to your specs, is this drive even capable of moving itself inside and outside of a vacuum in a meaningful way? I get that in the vacuum of space, any force, however tiny can push the drive (which is cool) but people are getting excited (prematurely so) about alternate applications (to include terrestrial) and other such claims like a hypothetical limit of .66 the speed of light, which seems unlikely. At this point in time, even if thrust exists, the force being generated seems rather weak, so such speculations really feel counter intuitive to what I have observed from Shawyer's videos and other DIYs. 

On another note, I can't help but notice no one is discussing your DIY build with the others setups on the SubReddit forum for EMdrive: https://www.reddit.com/r/EmDrive/

I'm sure there are a lot of people there who would be interested in your project.

Thanks

There was a big discussion on reddit, and we got many comments, hints and help from the people there. For example TheTraveller who calculated the stuff for Roger Shawyer.
Maybe the pause in discussion is that we were building our new setup which is almost - but still not - ready, so there were and are  no results available at this time.
There are several builds worldwide which measured some thrust, but it´s still not proven that this thrust came solely from the EMdrive and was not any parasitic force.
We are just another group trying to verify the theroy and trying to build a working setup. We plan to run the tests before the semifinals deadline on September 21st 2015

If there really is a tiny force - whoever proves that - then there is a good chance to develop an emdrive (with a superconducting cavity) that is capable of realizing the dreams of frictionless terrestric application like personal flying devices etc.
It´s like the invention of the steam engine which pushed the industrial revolution. 

This topic is quite new, it might prove wrong, but it might also prove right and give us another science fiction technology which might change the world.

If we really confirm thrust, then we will develop a flight version and hope to put it into a cubesat or pocketqub satellite. We willdefinitely send up a satellite with an EMdrive into space in case we win the Hackaday Prize - but don´t count goals that havent been shot yet :-D

Absolutely, Paul. Thanks and goodluck. Until then I'll stay tuned

To ensure you have a stable system try to comparise your beam like this:

Try to focus the laser on a small droplet of mercury and bounce that onto the splitter . Measure that . If the despersion  moves  the same amount as your em readings that your result can have a error caused by trembles. Mercury will react on any force that moves it. You will see fringes.

Mercury is not so harmless, I´ll try the simple approach first.

Alloys of gallium, indium and tin are harmless and liquid at room temperature.  You can use that in place of mercury: https://en.wikipedia.org/wiki/Galinstan

 I was thinking about the Koch island patch resonator and i suddenly remembered a Book about Fractals written by Denny Gulik a few year ago who, he was  talking about a curious phenomena that was observed by (as i remembered well) Christian Huygens in the 16th century, who notized that pendulum clocks syncronise themselves at some intervals.

Nobody knows how, but it happens.

Now my theory about this is,  that this phenomena can occur  in the cavity too, on atomic levels.
A nice experiment would be to try to modulate the frequenty of the microwaves (if your able too) to make a alternating resonator.

This question might be obvious but where can I find a parts description, etc

We are posting every update in the project logs, there´s a lot of valuable information already.
As the 2015HackadayPrize is running, there is no time to write descriptions now, we have to build up the setup.
The detailed descriptions will follow after the next deadline, including part lists, CAD files for 3D printed parts and more detailed instructions how to build the setup.

UPDATE: Much information can be found here: http://emdrive.wiki/Main_Page

oops i didn't understood that the cone is one cavity 

it is much more complicated then to add a second resonator

did you test the resonance Paul ?

Our previous setup was not able to test for resonance, and it was not tuneable.

The new setup has two methods of testing for resonance. We can measure the current of the power amplifier, which changes with SWR and we can detect RF energy directly which comes back from the feed with a small stub antenna near to the feed connector trace on the PCB. Both have been tested in the lab, but not yet in the cavity. Our new setup is still beeing built, but we aim to perform first tests before September 21st for the semifinals deadline.

why not add a second smaller inverted cone in the center?

Tell me why we should.

to maximize bouncing and resonance ??? 

Let´s make a deal - you give me a valid simulation and I make the experiment - no cost for you

how much cost you the cone ?

i imagine a second cone smaller in R and designed by you will cost less

a second cone should have a resonance to the rf source

and both cones should have resonance to each over

is this thinking wrong ?

Best way to say it is doing an extra design costs money and time. Plus they have to get the base theory down and get success. Without that it isn't even known if a new design would even work any better. So let them test the base design. We are seeing the information. They are actually doing this for a grade.

As the wavelength is about 12mm, a second cone inside our cavity would leave such small distance to the wall that the wave would not even get through to the other side, that´s why I wonder. Personally I don´t think this would make any sense, so I ask for a simulation. Maybe my thinking is wrong, but then prove me your idea is right - and I will consider to build it up. We are using proven designs because we don´t want to risk trying new ideas now without having a first working device.

could be working, but as Paul wrote: first get the first experiment working, than the rest!

Another idea popped in the goulash soup i call my brain: a multi cavity em drive. Make cavities inside the cavities, like a onion. 

I have similar thoughts. I keep wondering whether or not the actual shape of the cavity could have a significant impact in how this drive will or will not function. Multiple ocilators and cavities, open ended or slotted designs, etc. etc. It really stimulates the imagination and I'm anxious to see a proof of concept. This reference in EagleWorks article caught my attention in reference to a computer simulation one of those guys ran, 

"Dr. White’s computer analysis also shows that increasing the input power focuses the virtual particle flow from near omnidirectional at the low powers used in the NASA experiments, to a much more focused jet like beam at the higher power (kilowatts as compared to less than 100 Watts) used in the UK and China experiments." 

Well from the nasa tests, we know that the cavity shape isn't all that important as there was a drive called a canard drive that was tested at the same time as the emdrive. Both had similar designs, in that they were both copper vessels and both were pumped with microwaves. The canard drive also proposed a zero drive, or one that shouldn't have been able to move given all variables being the same per microwaves pouring into the vessel. They designed it so it had slits that opened to the outside air. Their zero drive failed as when it was tested, it was still giving off force. So funny enough design isn't all that important except for finding a way to make the process more efficient.

I like your ideas, I had the same one. As my theory is that actual force is coming from displaced electrons that are being hit from the inside of the vessel.

displaced electrons.. hmmm. 

That must be detectable with a electrometer inside the cavity...

In order to sense it you would actually have to put the sensing probes on both the inside and outside of the vessel. Issue is it would be hard as you have to protect the inside lead from microwave interference. Although a much simpler method of detection would be an electroscope. As the principal wouldn't be all that different from a electrostatic field.

Is it neccesary to make a one piece cavity? If not, you could also make a adjustable cavity with a design like a jet engine with adjustable choke..

Where do you attach the rf feed source? on a fixed point or can you slide it across the cavity?  I can see that youre able to adjust the endplate, is it no idea to adjust the rf source as well? 

The design for a sliding antenna feed is ready, we printed it in steel. But it will take some work to smoothen it from the inside and make the sliding mechanism ready.
So first we´ll focus on the silver cavity with fixed antenna feed.
What we can do is drilling another antenna hole into the cavity after the next tests and close the first one.

well you might attach a polishing brush on a powerdrill (use a clamp to fasten the cavity to a support) 

It just popped in my head : a tunable antenna! : make a antenna that works with spools that can be adjust ike a tuning unit in a transistor radio. 

To make measurements clearly visible; Why not place a laser pointer at a 5 degrees angle on the unit with the beam on the opposite wall, any changes and lift will be visual by a red dot moving on the wall.. 

The interferometer can do the same, but with more accuracy. By counting the fringe movements you can resolve half wavelength of the laser ( in our case ca. 300nm), with image processing of the fringes even fractions of that.
The advantage of  the interferometer is that the setup can be put into a box (or vacuum chamber) to avoid airflow.

With 3D printing its possible to print ceramics. You might try that and coat the inside with silver. The advantage of this is that you can beef up the power without melting the cavity. ( old ceramic insulators work like this too) 

I wish we had an RF source with that power :) Now we have a 500mW source in the 24GHz band.

Is it possible to contruct multiple 500 mW RF sources as a form of darlington unit? (thats combining 2 transistors to boost gain) ?

can you adjust the band? or is it fixed?

You could not measure an effekt, right? Dont worry, because emdrive do not work. It is all fake. For sure. All experiments in web, who show the effekt are fake.

Now you have verified. Believe in your results!

That´s funny, because I recently got an email telling me that the governments of the world are trying to kill me, because an Emdrive can be used as matter generator.
I call this BELIEFS.
As beliefs - and I assume your comment results also from a belief - are not reliable, I´d rather prefer to make some experiments.

PS: A comment for trolls:
Even if we don´t get any results - this project will have created many side products, like an USB milligram scale, wireless bridges, tracking software, laser interferometer, data acquisition and visualization software and a lot of experience gained.

Now i  think about it, the original cavity magnetron made  by Randall and Booth before the second world war had 6 cavities alternating to achieve maximum power. you might test a similar approach..  try multiple cavities and a cycling wire arrangement. you might also think about placing a magnet around the device to focus the waves

Sounds promising! : Did you try to make a concave cavity yet? or a cavity with arched ends? Sound funnels benefit from curved forms too. Now the microwaves make a angular pattern, a random angular pattern could boost the effect.  Or maybe a cluster of small cavities achieves more boost! 

We have a standard conical cavity with flat ends.
If we should measure a force, we will experiment with different shapes.
The simple shape is easy to build and is a design which showed results in others´ experiments already, so we stick to it in the first step.
With the silver 3D printing it will be easy to create complex forms.

If you ever need a elaborate 3d design: i can work pretty well with 3D programs and im able to make STL files. 

https://www.google.com/search?q=plasma+waveguide&ie=UTF-8&oe=UTF-8&hl=e