Yet another report from a DIY experiment showing NO thrust from an EM Drive and instead reporting thermal effects: https://www.reddit.com/r/EmDrive/comments/3kxvjr/emdrive_build_update_5/
Absolutely no one, has ever replicated the claims of Shawyer and Yang (who never reported a single test performed in vacuum and therefore never properly accounted for thermal effects).
l
Well if I used dimensions meant for a 900mhz rf source with a 2.45ghz rf source to test a theory involving "and the Q is important" I'm not sure it bricking is going to tell me much useful information.
On the contrary, if a cavity of given dimensions resonates at a lower frequency, it will certainly also resonate at higher frequencies, and the higher the frequency the closer to each other (on a % basis) are the natural frequencies to each other.
True, that said I remain relatively sure that taking a frustum designed for a 900 (and change) mhz industrial magnetron, hooking a 2.45 Ghz consumer magnetron to it via coax feed of a random length and expecting it to do something without any further tuning (except burn a potato), is probably not the way to go.
Yet another report from a DIY experiment showing NO thrust from an EM Drive and instead reporting thermal effects: https://www.reddit.com/r/EmDrive/comments/3kxvjr/emdrive_build_update_5/
Absolutely no one, has ever replicated the claims of Shawyer and Yang (who never reported a single test performed in vacuum and therefore never properly accounted for thermal effects).
l
Well if I used dimensions meant for a 900mhz rf source with a 2.45ghz rf source to test a theory involving "and the Q is important" I'm not sure it bricking is going to tell me much useful information.
On the contrary, if a cavity of given dimensions resonates at a lower frequency, it will certainly also resonate at higher frequencies, and the higher the frequency the closer to each other (on a % basis) are the natural frequencies to each other.
Pick any one of the frequencies out of a consumer magnetron to start, but first figure out whether it's driven by a single HV diode @ 220 VAC 50 Hz or a 220 VAC Inverter @ 50 Hz (South Africa's power grid is 220VAC @ 50 Hz). If it's a single HV Diode PS driving it then the range for harmonics and shifting frequencies will be greater than a Inverter which operating frequencies should be on the order of 20 KHz into the HV coil and a more stable output.
Whether his magnetron will provide a output that excites the frustum is anyone's good guess considering these two facts. There is no bad data. He gets a A for doing it.
Shell
Got the new magnetron and inverter late this afternoon (yea!!!), been waiting for a long time it seems. Tomorrow I'll start to get the inverter power supply and magnetron mounted on the Aluminum plate and wiring it. I still need to build a 555 timer to provide a data good signal to switch on the inverter without the front panel controls.
Shell
What I learned this week:
Most replacement magnetrons have an advertised frequency center at 2460, not 2450.
A standard non-inverter microwave on 60hz power produces 4250v pulses at twice the line frequency, on for 8.3 ms, off for 8.3 ms.
With 2 caps and another diode you can replace the
https://en.wikipedia.org/wiki/Voltage_doubler#Villard_circuit output stage with a
https://en.wikipedia.org/wiki/Voltage_doubler#Greinacher_circuit . This provides continuous power output instead of pulsed.
You MUST cut the leads to the heater and supply power to them separately before running the magnetron grid on DC. The heater uses an RF choke to pull the HV down to 3-4 volts DC in a stock mangetron. Running 4.3kv through it will kill it and possibly you.You can use oven diodes for this, but the oven caps aren't rated for the voltage. I found 10kv film capacitors on ebay for <$25. For safety add bleeder resistors to these caps.
Now I have a new question: How can I further change the output voltage and/or current limit this? That's this week's project.
Thanks in advance for the advice.
What I learned this week:
Most replacement magnetrons have an advertised frequency center at 2460, not 2450.
A standard non-inverter microwave on 60hz power produces 4250v pulses at twice the line frequency, on for 8.3 ms, off for 8.3 ms.
With 2 caps and another diode you can replace the https://en.wikipedia.org/wiki/Voltage_doubler#Villard_circuit output stage with a https://en.wikipedia.org/wiki/Voltage_doubler#Greinacher_circuit . This provides continuous power output instead of pulsed.
You can use oven diodes for this, but the oven caps aren't rated for the voltage. I found 10kv film capacitors on ebay for <$25. For safety add bleeder resistors to these caps.
Now I have a new question: How can I further change the output voltage and/or current limit this? That's this week's project.
Thanks in advance for the advice.
You have a schematic of your power supply?
Shell
Here is one way.
http://www.google.com/patents/US4383156
What I learned this week:
Most replacement magnetrons have an advertised frequency center at 2460, not 2450.
A standard non-inverter microwave on 60hz power produces 4250v pulses at twice the line frequency, on for 8.3 ms, off for 8.3 ms.
With 2 caps and another diode you can replace the https://en.wikipedia.org/wiki/Voltage_doubler#Villard_circuit output stage with a https://en.wikipedia.org/wiki/Voltage_doubler#Greinacher_circuit . This provides continuous power output instead of pulsed.
You can use oven diodes for this, but the oven caps aren't rated for the voltage. I found 10kv film capacitors on ebay for <$25. For safety add bleeder resistors to these caps.
Now I have a new question: How can I further change the output voltage and/or current limit this? That's this week's project.
Thanks in advance for the advice.
You have a schematic of your power supply?
Shell
No, I'll draw one when I get home.
I didn't mention that you must -must- cut the leads to the filament heater before running the magnetron DC. I'll edit that immediately.
Never!
I can't claim to be a scientist as much as I would like to be able to. I did some ground breaking programming while in government. But few people saw the ground.
You're probably as near old as me. Possibly you remember this from college:
"Behold the turtle. They only make progress when they stick their heads out."
(Revised to compensate for 1970's sexism.)
Bob
Never!
I can't claim to be a scientist as much as I would like to be able to. I did some ground breaking programming while in government. But few people saw the ground.
You're probably as near old as me. Possibly you remember this from college:
"Behold the turtle. They only make progress when they stick their heads out."
(Revised to compensate for 1970's sexism.)
Bob
Hehe, haven't heard that one in 45 years Bob. And we know which one won that classic race, between the Tortoise and the Hare.
Shell
New emdrive build head's up:
https://www.reddit.com/r/EmDrive/comments/3l4clo/emdrive_build_update_version_001/Interesting test bed configuration; he's just getting started. Laser powered rather than magnetron. A little different, but hey, everyone has a right to start somewhere. Should be interesting!
NSF-1701 Update: New LDS display meter on its way. Will be installing it into an old PC where I'll use its power supply to fire up the LDS and also DAQ inputs. The display is simply a good visual tool, the DAQ will give me the tabular data for chart creating, etc.
I also will be experimenting around with labview or its open source equivalent. Figure an old PC is fine for DAQ stuff, but am still cautious about relying on it too much in high EM fields...thus the shielded LDS display module which is designed to work in tough industrial environments, heat, vibration, EM fields, etc.,
New emdrive build head's up:
https://www.reddit.com/r/EmDrive/comments/3l4clo/emdrive_build_update_version_001/
Interesting test bed configuration; he's just getting started. Laser powered rather than magnetron. A little different, but hey, everyone has a right to start somewhere. Should be interesting!
NSF-1701 Update: New LDS display meter on its way. Will be installing it into an old PC where I'll use its power supply to fire up the LDS and also DAQ inputs. The display is simply a good visual tool, the DAQ will give me the tabular data for chart creating, etc.
I also will be experimenting around with labview or its open source equivalent. Figure an old PC is fine for DAQ stuff, but am still cautious about relying on it too much in high EM fields...thus the shielded LDS display module which is designed to work in tough industrial environments, heat, vibration, EM fields, etc.,
take a look at this:
http://www.myopenlab.de/startseite/downloads.htmlDocumentation is in German and Spanish, but the installer permits a choice of English. If you speak German or Spanish, you're home free.
English forum:
http://myopenlab.informe.com/myopenlab-english-df1.html
New emdrive build head's up:
https://www.reddit.com/r/EmDrive/comments/3l4clo/emdrive_build_update_version_001/
Interesting test bed configuration; he's just getting started. Laser powered rather than magnetron. A little different, but hey, everyone has a right to start somewhere. Should be interesting!
NSF-1701 Update: New LDS display meter on its way. Will be installing it into an old PC where I'll use its power supply to fire up the LDS and also DAQ inputs. The display is simply a good visual tool, the DAQ will give me the tabular data for chart creating, etc.
I also will be experimenting around with labview or its open source equivalent. Figure an old PC is fine for DAQ stuff, but am still cautious about relying on it too much in high EM fields...thus the shielded LDS display module which is designed to work in tough industrial environments, heat, vibration, EM fields, etc.,
take a look at this: http://www.myopenlab.de/startseite/downloads.html
Documentation is in German and Spanish, but the installer permits a choice of English. If you speak German or Spanish, you're home free.
English forum: http://myopenlab.informe.com/myopenlab-english-df1.html
Thanks! Will download this tonight. Have a 10=bit A/D module coming in as well as the new LDS display in a few days.
I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation
some more vids are available
I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation
...
some more vids are available
Interesting video...
So all we have to do is pressurize a cone and heat it up, and we should get a net thrust?
OK, an extension:
Behold the oyster. You only get the pearl when the Shell opens up.
Find that thrust. Try and try again. Then repeat.
OK, an extension:
Behold the oyster. You only get the pearl when the Shell opens up.
Find that thrust. Try and try again. Then repeat.
urk. You bet Bob, I'm not Shell Shocked.
Hmm...
I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation
1 - One of my first posts here (way back in thread one) dealt with this - that the EM Drive moved on account of its shape.
2 - I was told the concept violated the laws of thermodynamics. So, given that, are these simulations legit?
Ok, thought experiment. Say we use actual physical objects instead of photons. maybe old fashioned 'super balls' or something similar, though unlike photons they would slow down. A frustum in a zero G environment. Would the results match the simulation?
I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation
...
some more vids are available
Interesting video...
So all we have to do is pressurize a cone and heat it up, and we should get a net thrust?
Back in thread three this was discussed briefly in the context of ionized particles. Yang stated in one of her papers that the behaviour of ionized particles was important to understanding the behaviour of EM Drives. It has been pointed out numerous times that neither Yang or Shawyer published experiments ran in vacuum.
At one point I called this the "ionic wind tunnel" effect in those discussions. That said, these were general discussions and everyone felt that microwave energy was the primary source for trust...
Now we have some excellent simulations that bring this all back. Note that, say, nitrogen ions are orders of magnitude more massive than photons.
In my view, these simulations are a significant step forward in our understanding of this phenomena.
Congratulations!And once again I am in awe of the power of these forums!
@SeeShells,
Here are some views of the CE3 model. They are very preliminary but ... well, its as far as I have gotten.
https://drive.google.com/folderview?id=0B1XizxEfB23td2ZDeDFUUFdvLUk&usp=sharingIt resonates but it's not a mode that I recognize.
Specifics-
Cavity is the SeeShell Crazy Eddie 2, upgraded by replacing the loop antenna with wave guides, hence CE3 model.
Drive frequency 2.47 GHz, Harminv calculated resonant frequency 2.47837658E+009 Hz, Q is good: ~ 1 million.
Antenna - dual magnetron wave guides, 180 degrees apart. That is, on opposite sides of the frustum using WR 340 wave guides with bottom edge flush with the big base. Phase is adjusted to place sources 3 wavelengths apart.
Gaussian noise bandwidth at 0.05 * 2.47GHz is is double the expected magnetron noise bandwidth.
This is a debug run at resolution = 200, hence it may appear more granular than the resolution = 250 runs commonly uploaded. There are no csv files, resolution of 200 would adversely affect any data comparison calculations based on the csv files.
