If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #58454
Joined: Thu Feb 18 2016, 06:33AM
Location:
Posts: 23
This article gives a skeptical review of the experiments testing the EM-drive:
SCIENCE — NASA’s EM-drive still a WTF-thruster. New paper generates more noise than experimental thrust. CHRIS LEE - 11/22/2016, 5:17 PM
The researchers measured 128 micronewtons at 60 watts in vacuum. The problem is this thrust is very small so its difficult to rule out experimental errors. It's about the weight of a grain of sand.
They would be better off to redo the experiment at much higher powers. This actually isn't that hard to do. For instance common household microwave ovens put out 1,000 watts. So using six of these to get 6,000 watts you should get, if it is a real effect, in the range of 12.8 milliNewtons, or 12.8/9.81 = 1.3 milliKilograms-force = 1.3 grams-force. Forces at this weight range, about the weight of a cubic centimeter of water, are commonly measured in university labs.
In fact, this could probably tested by amateurs or university students. You can find amateur experimenters who have posted on the net various (dangerous!) experiments with microwave generators, magnetrons, taken from out-of-use microwave ovens:
Crazy Ukrainians Experiment with Microwaves. Lindsay Handmer at 10:01 AM Jul 30 2014 ,390449
The hardest part would be doing the EM-drive experiment in a vacuum though. Experiments showing positive results that have been done in air can be discounted because air currents can be the cause of the results observed.
For instance, here's an amateur doing a test of the EM-drive in air showing positive results. Numerous commenters to the video observed the results are unreliable because of the effect of heated air generating rising air currents:
EmDrive Test No.03 Success, I have thrust !!! - YouTube.
For an amateur though doing the experiment at high power in a vacuum chamber would be expensive because of the large size of the required vacuum chamber able to hold six 1,000 watt magnetrons. What might work is to use a waveguide to direct all the microwave energy to a small area that can be enclosed in a small vacuum chamber.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141
I doubt that approach will help, . getting 6 magnetrons to reliably phase-lock would require a lot of experimentation . if the microvaves enter via a waveguide, this may add its own forces when carrying microwave power (electromagnetic waves have momentum) . 6 times more signal power from 6 times the weight and volume does not help much.
I have avoided playing with domestic magnetrons because the hv, and especially the rf, scare me, and I've never had a use that outweighed these two concerns. I used to work on a LINAC, using 4x 20 MW klystrons so I understand the physics a little, here is a fairly recent document that I came across which may help a little
Registered Member #58454
Joined: Thu Feb 18 2016, 06:33AM
Location:
Posts: 23
Sulaiman wrote ...
I doubt that approach will help, . getting 6 magnetrons to reliably phase-lock would require a lot of experimentation . if the microvaves enter via a waveguide, this may add its own forces when carrying microwave power (electromagnetic waves have momentum) . 6 times more signal power from 6 times the weight and volume does not help much.
I have avoided playing with domestic magnetrons because the hv, and especially the rf, scare me, and I've never had a use that outweighed these two concerns. I used to work on a LINAC, using 4x 20 MW klystrons so I understand the physics a little, here is a fairly recent document that I came across which may help a little
Wow! Was that 100 MW total power continuous???
Some of these amateurs do experiments with multiple microwave generators combining their power:
TRIO OF MAGNETRONS POWER A MICROWAVE RIFLE. Dan Maloney October 22, 2016
Obviously if such is to be done in a university undergraduate lab it would have to be done under microwave expert supervision.
About the waveguide addings its own forces, the proposers of the EM-drive have considered that, and argue the results they've seen are orders of magnitude higher than that due to electromagnetic wave's momentum.
Registered Member #72
Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659
From what I read of the recent NASA vacuum experiments, a lot of the odd behaviour seemed to be due to the heating of the apparatus when under power, so unwanted/assymetrical torsion beam expansion rather than aircurrents. Without better experimental design, increasing the operating power would just increase the uncertainties. The interdigitated electrostatic calibration motor was quite capable of generating nice crisp torque steps, so there was no issue with sensitivity even down at that low power level. At its very least, the technique has to show torque/thrust monotonic with input power, and IIRC even that wasn't achieved.
Registered Member #2906
Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727
Robert, dont make a fool out of your self, this magnetron combining is fake as fuck. There is neither a appropriate power delivery system on their stick nor do they wear any eye protection.. which is the one body part thats most susceptible to RF heating. Even if this thing does actually output RF energy, think again if those 4 batteries could ever deliver the power to even drive one magnetron to its full potential. The whole thing is a piece of shit (technically). I guess its fine if you call it art-work.
Registered Member #135
Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735
Yea a real setup would require those magnetrons be connected to some rectangular transition (it'd be huge, like 2" x 4" transition) then it would have to be coupled to a "Magic Tee" to sum the power. All of which have to be silver plated, and even then it would get very hot. The magnetrons would probably arc over constantly because they are not really being loaded, or would probably burn out faster because of reflected power.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141
I disagree;
They are generating short intense microwave pulses, so do not need huge batteries, and body-part damage due to heating is minimal. (I'm of the opinion that there is more to rf damage to humans than just thermal effects, but I'm in the minority)
The horn antenna would load the magnetrons, it is a fairly efficient transmit antenna.
Magnetrons can be 'tuned' to phase lock, as they mentioned in the video.
The rf interference on the video gives a good clue to operation.
Would you walk back home through town wearing those outfits if you did not have to ?
I think that at least some of the video is real, and realistic.
I'm unable to do the math for the e.m. drive and I don't really understand it so I can't comment other than, whether it works or not, it will not make any difference to me in my little shed/workshop/lab/hideaway :)
Registered Member #42796
Joined: Mon Jan 13 2014, 06:34PM
Location:
Posts: 195
i don't get how the EM drive could ever generates trust... wouldn't the microwaves also bounce from the cone walls thus negating the top and bottom plates bounce inequality?
Registered Member #2906
Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727
Sulamain.. which EM interference? You mean the video editing to simulate image sensor artifacts? All that why they press the trigger and simulate the thing would have some kind of recoil to make it more like shooting something? One question: why would an image sensor be affected (and that only partially at a time, so you can still see the action for youtube!!), but the MP4 or whatever encoding processor works flawlessly... do you have ever seen a blocky corrupted encoded file? Guess what, it wouldnt look good on youtube. Also have you ever seen an overloaded image sensor due to laser damage? Those image artefacts take a lot of time to vanish... also the purple nature of the artifacts is very interesting. Somehow the 2.45GHz of the magnetrons manage to excite only the blue and red sensors, but not the green ones which there are twice as much of.... Please, think critically; dont say its true because you wish it was.. And its not a short pulse. The duration of the simulated image sensor artefacts (if they were true) can last a second or more... 3 Magnetrons would have a power of at least 2kW... this means 2000J energy delivery.... you are on the forum long enough to know how a 2kJ energy storage looks like... i just wonder why you ignore the basics. unbelievable that one has to debunk a video like this on a forum like that. shouldnt happen.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Amateurs testing the EM-drive?
