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#3520
by
Bob Woods
on 06 Jun, 2018 15:19
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Data content looks good. Couple of minor suggestions/questions. What's the A/D resolution on each channel? Can you increase the sample rate? i.e. your ambient RF channel rise & fall times are awfully slow sample speeds. Don't know if it will ever matter, but transient events or simple power on/off events may have ringing which could matter which can't be seen at your current sample rates.
With a little processing, it seems I can get some pretty good data. I am having a voltage issue with the amplifier temp skipping, but that can be subtracted easily. Overall, I'm very pleased with the quality of the data collected on the first run. 
Two things I noted is that the pendulum appears a little over-damped. That is easy to fix by lowering the damping fluid reservoir. And second that the 6.8uN of thrust appears to be mostly related to the temperature of the amplifier MOSFET...
Nomenclature suggestion: Push To Talk is a little cryptic, describing an action rather than a source.
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#3521
by
Monomorphic
on 06 Jun, 2018 15:55
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Nomenclature suggestion: Push To Talk is a little cryptic, describing an action rather than a source.
I'm open to suggestions on better wording. It is a logic level enable pin that requires grounding to enable power to the amplifier, which can also be used for a PTT/KEY control.
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#3522
by
chongma
on 06 Jun, 2018 22:05
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Two things I noted is that the pendulum appears a little over-damped. That is easy to fix by lowering the damping fluid reservoir. And second that the 6.8uN of thrust appears to be mostly related to the temperature of the 30W RF output GaAs FET...
we haven't heard from Rodal in a while. he usually gives good advice about damping
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#3523
by
oyzw
on 07 Jun, 2018 00:32
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As for the phenomenon of self-resonance in RF circuits, I have also observed that I have tested my own design of the cavity and peaked at the predetermined TE013 resonance point, but there is a strong peak in the distance not far from the cavity. The resonance mode does not exist in the intrinsic mode. So there is a similar situation in Professor Tajmer's test chart. In short, the coupling of emdrive is difficult
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#3524
by
TheTraveller
on 07 Jun, 2018 01:03
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The miniVNA tiny+ has shipped. Should take max 10 days to arrive.
I would have gone with the Windfreak SynthNV2. For an extra $120 you get so much more. 18dB of drive vs -6dB. So if you expect to use it or the cheap chinese signal generator (-10dB drive), you will need a pre-amp to get the full 100W from your amplifier - which adds complexity.
Remember that I also own the miniVNA tiny and don't you recall that it would return ridiculous numbers for return loss, like -50 to -60dB? The only thing is it useful for is the Smith Chart function, IMHO. The cheaper + version you ordered doesn't seem to have many changes except access to lower bandwidth.
I also hope you purchased the calibration kit because you will need it to get the miniVNA to work.
Jamie,
It is claimed the miniVNA tiny+ is an improved build. Will see. Lower price only on AliExpress. Higher price elsewhere.
As for the output, at 2.5GHz it drops to around -20dBm. Don't plan to use it to drive the Rf amp. It was bought to tune the coupler. Yes I did buy the calibration kit.
Will checkout the Windfreak SynthNV2. Was not aware of that unit. Thanks.
It Is Time For The EmDrive To Come Out Of The Shadows
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#3525
by
SteveD
on 07 Jun, 2018 01:31
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Interesting. Dave reported a noticeable force on his last run, where the magnetron was known to be defunct. The self contained nature of monomorphic's setup seems to negate the hot wire expanding hypothesis. Heated air would seem a likely cause. On the other hand, a heat engine also produces an observable force when it gets hot. I have to wonder if a hot device might be putting out IR photons across a wide enough band that some randomly are the right frequency to be in resonance in the can. Would help explain why polishing to a mirror finish seems important for what should be microwave resonance.
Just to be clear, a more mundane heat related cause seems likely.
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#3526
by
TheTraveller
on 07 Jun, 2018 01:50
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As for the phenomenon of self-resonance in RF circuits, I have also observed that I have tested my own design of the cavity and peaked at the predetermined TE013 resonance point, but there is a strong peak in the distance not far from the cavity. The resonance mode does not exist in the intrinsic mode. So there is a similar situation in Professor Tajmer's test chart. In short, the coupling of emdrive is difficult
Oyzw,
Correct.
Which is why DIYers need to be able to use an E field probe inside the cavity and determine they are exciting a real cavity resonant mode, not some Rf system resonance, and that mode is the one they wish to excite.
Plus the coupler design and position must create opposite direction travelling waves so their superposition creates the resonant lobes they simulate.
Caution is always needed with TE01x modes as the degenerative TM11x mode resonates at the same or very near freq. Coupler design and position is what determines which mode is excited and which mode is suppressed. This is again why an E field probe is very important to ensure you are exciting TE01x mode and not TM11x mode.
It Is Time For The EmDrive To Come Out Of The Shadows
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#3527
by
TheTraveller
on 07 Jun, 2018 02:48
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2 x 0.55 x 450 x 900mm 110 Cu sheets arrive today.
Next steps after the silver epoxy arrives:
Remove the protective film on one side of one sheet,
Tape one sheet to a 900mm x 900mm white melamine covered work board,
Mirror polish the sheet, NO SCRATCHES ALLOWED!
Scribe the frustum curves on the sheet. Will describe how to do this later.
CAREFULLY cut out the frustum shape,
Clean up the cut edges. Will later describe and show how to grind the big and small diameter edges flat or at right angle to the frustum length axis.
Cut and apply the protective film to the mold,
Wrap the cut frustum around the flower pot form with the aid of the hoop rings,
Fit all 5 hoop rings over the wrapped frustum,
Carefully align the edges of the cut frustum. This is a critical step to get 100% right.
Epoxy the hoop rings to the frustum. No need to use silver epoxy here. Don't use 5 minute epoxy.
Wait 24 hours for the epoxy to cure,
Apply silver epoxy on outside of the butt join seam,
Apply 5 shaped reinforcing pieces of silver epoxy lined copper sheets between the hoop rings to add strength to the butt joint,
Wrap scrap wire over the copper pieces to hold them in place during silver epoxy curing,
Wait 24 hours for the silver epoxy to cure,
Remove the securing wire,
Pull the frustum away from the flower pot mold,
Remove the protective film,
Using a sharp pointed tooth pick carefully fill in any gaps in the butt joint inside the frustum with silver epoxy,
Wait 24 hours for the epoxy to cure,
Repolish the epoxied butt joint area if required,
BTW wear thin white cotton gloves at all times. Change them quite often. They protect your fingers and hands from copper cuts and protect the copper from your finger prints. Always wear a new pair when touching the inside highly polished surface of the frustum.
Any comments?
It Is Time For The EmDrive To Come Out Of The Shadows
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#3528
by
kubajed
on 07 Jun, 2018 06:10
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Hi,
my name is Jakub Jędrzejewski, also known as a “polish team”. Previously I was working with my friend, but we decided to split up, so now I am working on my own.
I would like to introduce my work: two cavities, two test stands and results obtained. The microwave generating system I used in first and second tests is the same so I would like to describe it at first. It is quite similar as James’s. To power it batteries are used. Communication in the first test was done via WiFi, in the second using radio. Maximum output power is about 25 W.
My first cavity have been demonstrated there already, it was shaped like a cone with a cylinder where a piston was used to match the impedance. I use aluminum casting, then it was turned to the desired dimensions. The first test stand acts like a teeter totter. The main disadvantage of this test stand is that it is built using steel, which is ferromagnetic material.
The second test stand is similar to the James’s one, but I use 1,5 um LDS, batteries to power, and radio communication. I changed dimensions of the first cavity and now it hasn’t got cylindrical part, additionally it is polished internally. Material used to manufacture whole test stand is aluminum. I have also built bidirectional power meter. Calibration have been done with a coil and a ferromagnetic screw, at first I measured force on the 0,1 mg scale, then I moved everything onto test stand. The results on the torsion pendulum are the first ones, so future test will be performed. Maybe cavity during testing wasn't properly impedance matched.
Photographs are available here:
First test stand:
https://drive.google.com/open?id=1o0C5tsZ3T_HzWdI5NNC8U0IjVX5cRnKXSecond test stand:
https://drive.google.com/open?id=1WueFLUnx3Afe0Tsx6qekSZhmVwDfyMrN
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#3529
by
ThatOtherGuy
on 07 Jun, 2018 08:34
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using either a thinner wire, or increasing the wire length will increase the sensitivity of the rig
However, i'm nearly at the limit of my LDS resolution.
Aside from the resolution issue; if you want to increase the wire length, you may place a (plastic) pipe of appropriate diameter (and length btw) on the top of the test rig box, at that point, the high end of the wire will be anchored at the upper end of the pipe; the idea is to use the pipe to shield the wire from air movement, although, I suspect that such a setup may/will induce a "chimney" effect and I'm not sure if/how it will impact the measurements
Anyhow, you're doing a really
IMPRESSIVE job !
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#3530
by
TheTraveller
on 07 Jun, 2018 10:00
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Hi,
my name is Jakub Jędrzejewski, also known as a “polish team”. Previously I was working with my friend, but we decided to split up, so now I am working on my own.
I would like to introduce my work: two cavities, two test stands and results obtained. The microwave generating system I used in first and second tests is the same so I would like to describe it at first. It is quite similar as James’s. To power it batteries are used. Communication in the first test was done via WiFi, in the second using radio. Maximum output power is about 25 W.
My first cavity have been demonstrated there already, it was shaped like a cone with a cylinder where a piston was used to match the impedance. I use aluminum casting, then it was turned to the desired dimensions. The first test stand acts like a teeter totter. The main disadvantage of this test stand is that it is built using steel, which is ferromagnetic material.
The second test stand is similar to the James’s one, but I use 1,5 um LDS, batteries to power, and radio communication. I changed dimensions of the first cavity and now it hasn’t got cylindrical part, additionally it is polished internally. Material used to manufacture whole test stand is aluminum. I have also built bidirectional power meter. Calibration have been done with a coil and a ferromagnetic screw, at first I measured force on the 0,1 mg scale, then I moved everything onto test stand. The results on the torsion pendulum are the first ones, so future test will be performed. Maybe cavity during testing wasn't properly impedance matched.
Photographs are available here:
First test stand: https://drive.google.com/open?id=1o0C5tsZ3T_HzWdI5NNC8U0IjVX5cRnKX
Second test stand: https://drive.google.com/open?id=1WueFLUnx3Afe0Tsx6qekSZhmVwDfyMrN
Jakub,
Both of your experimental results I suggest are the result of thermal expansion. The force plots are not the force plots produced by an EmDrive generating force.
Your frustum is cutoff as shown by the intensity of the small end plate eddy current ring being lower than the small end side wall eddy current ring.
Stay tuned for how to build a KISS thruster, coupler, Rf system and rotary test rig that will generate enough force to rotate the rotary test rig round and round.
It Is Time For The EmDrive To Come Out Of The Shadows and For EmDrive DIYers To Stop Wasting Time and Money On Builds That Will Not Generate Significate Force
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#3531
by
TheTraveller
on 07 Jun, 2018 11:26
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There is not a nice way to say this. The EmDrive NEEDS TO BE FREE to accelerate. Any test rig that does not allow the EmDrive to freely accelerate is a waste of time, no matter how well it is built. F = m * a. No a or acceleration and no F or force. Understand?
The EmDrive IS NOT A ROCKET engine. There is NO force generation if the EmDrive is not free to accelerate. I will not argue this point. It is a FACT as I will show.
Building a FREE TO ACCELERATE rotary test rig is how to do this. Stay tuned and see it in action. Plus learn all the other tricks and techniques you need to add to the recipe to make this work.
Or continue to follow failed examples, waste your time and money and achieve nothing. Your choice.
It Is Time For The EmDrive To Come Out Of The Shadows and For EmDrive DIYers To Stop Wasting Time and Money On Builds and Test Rigs That Will Not Generate Significate Force
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#3532
by
Monomorphic
on 07 Jun, 2018 11:45
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There is not a nice way to say this. The EmDrive NEEDS TO BE FREE to accelerate. Any test rig that does not allow the EmDrive to freely accelerate is a waste of time, no matter how well it is built. F = m * a. No a or acceleration and no F or force. Understand?
You do realize a torsional pendulum is no different from your rotary test rig? Torsional pendulums are free to accelerate, as evidenced by the thermal effects seen here lately. If the Emdrive needs to accelerate to work, then why didn't the effect kick in when it began accelerating from the thermal effects?
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#3533
by
TheTraveller
on 07 Jun, 2018 12:37
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There is not a nice way to say this. The EmDrive NEEDS TO BE FREE to accelerate. Any test rig that does not allow the EmDrive to freely accelerate is a waste of time, no matter how well it is built. F = m * a. No a or acceleration and no F or force. Understand?
You do realize a torsional pendulum is no different from your rotary test rig? Torsional pendulums are free to accelerate, as evidenced by the thermal effects seen here lately. If the Emdrive needs to accelerate to work, then why didn't the effect kick in when it began accelerating from the thermal effects?
Jamie,
Any EmDrive thruster needs to be excited in a E probe verified TE01x mode, have a good side wall coupler design that generates bi directional travelling waves plus needs to have a small end that is not in cutoff.
The Jakub results are thermal and their frustum was a bad build. It operated in cutoff, coupler design and placement can't generate bidirectional travelling waves, those that designed and built it ignored the TE01x 0.82 cutoff rule and visual data that showed it was cutoff.
As I stated I'll not argue the point. My results will reveal reality.
It Is Time For The EmDrive To Come Out Of The Shadows and For EmDrive DIYers To Stop Wasting Time and Money On Builds and Test Rigs That Will Not Generate Significate Force
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#3534
by
Monomorphic
on 07 Jun, 2018 13:07
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Any EmDrive thruster needs to be excited in a E probe verified TE01x mode, have a good side wall coupler design that generates bi directional travelling waves plus needs to have a small end that is not in cutoff.
Phil,
Are you saying that the infrared camera technique is not sufficient to verify modes?
I am more than willing to verify the mode using an e-probe. It shouldn't take long since I already have an e-probe I can modify handy.
As for a sidewall coupler, that will be tested in time, likely with Oyzw's spun copper frustum.
Both my 3D printed frustum and Oyzw's frustum are confirmed to have small ends that are not in cutoff.
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#3535
by
TheTraveller
on 07 Jun, 2018 13:31
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Any EmDrive thruster needs to be excited in a E probe verified TE01x mode, have a good side wall coupler design that generates bi directional travelling waves plus needs to have a small end that is not in cutoff.
Phil,
Are you saying that the infrared camera technique is not sufficient to verify modes?
I am more than willing to verify the mode using an e-probe. It shouldn't take long since I already have an e-probe I can modify handy.
As for a sidewall coupler, that will be tested in time, likely with Oyzw's spun copper frustum.
Both my 3D printed frustum and Oyzw's frustum are confirmed to have small ends that are not in cutoff.
Jamie,
I believe those are EW thermal images and not your cavities? E field probe results are superior to thermal plots and are much quicker and lower cost to obtain than thermal plots. Please note the EW copper PCB end plates are 35um or 0.0014 inches thick, 1 oz copper, and as such do not easily distribute heat sideways plus the heat needs to transit the fibreglass backing material to be imaged. Bit harder to do thermal images of the side walls as they are 20x thicker.
Please post the Feko mode plots showing the end plate and small end side wall eddy current plots to confirm the cavities are not in cutoff.
Next goal is to use a side wall mounted stub antenna / coupler and to use a VNA / Smith Charts to tune the distance from the big end plate, antenna length and angle to the side wall for best impedance match and lowest VSWR when it is exciting an E probe verified TE013 mode and not TM113 or some other close mode.
Only trying to be helpful and to help you to measure significant force generatiion.
It Is Time For The EmDrive To Come Out Of The Shadows and For EmDrive DIYers To Stop Wasting Time and Money On Builds and Test Rigs That WILL NOT Generate Significate Force
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#3536
by
PotomacNeuron
on 07 Jun, 2018 13:31
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Phil,
Are you saying that the infrared camera technique is not sufficient to verify modes?
I am more than willing to verify the mode using an e-probe. It shouldn't take long since I already have an e-probe I can modify handy.
As for a sidewall coupler, that will be tested in time, likely with Oyzw's spun copper frustum.
Both my 3D printed frustum and Oyzw's frustum are confirmed to have small ends that are not in cutoff.
Monomorphic, your E probe looks like a loop antenna, thus a B probe. I think an E probe is small enough to probe the internal of a cavity through small holes drilled on the walls. That is also what I read from TheTraveller's description.
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#3537
by
TheTraveller
on 07 Jun, 2018 13:38
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Phil,
Are you saying that the infrared camera technique is not sufficient to verify modes?
I am more than willing to verify the mode using an e-probe. It shouldn't take long since I already have an e-probe I can modify handy.
As for a sidewall coupler, that will be tested in time, likely with Oyzw's spun copper frustum.
Both my 3D printed frustum and Oyzw's frustum are confirmed to have small ends that are not in cutoff.
Monomorphic, your E probe looks like a loop antenna, thus a B probe. I think an E probe is small enough to probe the internal of a cavity through small holes drilled on the walls. That is also what I read from TheTraveller's description.
PN,
Drill the small diameter E probe access hole in the centre of the big end plate. Should be no E field there, if excited in TE01x mode as it should be a 1/2 guide wave null zone, and min / no reduction in Q. If there is a strong E field as the E field probe is inserted in the small hole in the centre of the big end plate, well this is not TE01x mode.
It Is Time For The EmDrive To Come Out Of The Shadows and For EmDrive DIYers To Stop Wasting Time and Money On Builds and Test Rigs That WILL NOT Generate Significate Force
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#3538
by
Monomorphic
on 07 Jun, 2018 13:44
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Monomorphic, your E probe looks like a loop antenna, thus a B probe. I think an E probe is small enough to probe the internal of a cavity through small holes drilled on the walls. That is also what I read from TheTraveller's description.
I understood that as well. The image I used is of the B-probe that I use to sniff around. I'll remove that and replace it with an e-probe, which is basically a very thin coax inserted through a hole. I will drill a hole in the small end and insert there likely.
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#3539
by
Monomorphic
on 07 Jun, 2018 13:46
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Drill the small diameter E probe access hole in the centre of the big end plate. Should be no E field there, if excited in TE01x mode as it should be a 1/2 guide wave null zone, and min / no reduction in Q. If there is a strong E field as the E field probe is inserted in the small hole in the centre of the big end plate, well this is not TE01x mode.
I am going to go down through the small end about half radius out. If I insert the probe all the way down, I should be able to detect three distinct lobes. I don't want to scar up the large end-plate as it is harder to replace.
