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#4020
by
zen-in
on 22 Jul, 2016 21:26
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Saw this placed under the EM drive topic elsewhere online.
Newly discovered material property may lead to high temp superconductivity
http://m.phys.org/news/2016-07-newly-material-property-high-temp.html
There have been many compounds that have appeared to exhibit room temperature superconductivity, based on critical transition temperature measurements. The tests have been done on single crysals or other small samples. Scaling that up to a superconducting cable or anisotropic sheet is another story. It would transform many industries if the yield was high and production costs low. Right now experimentation with superconductors is within the reach of almost anyone. High temperature superconductors are available from many sources and liquid Nitrogen can be purchased at most welding shops. Just bring your own dewar or a vacuum thermos with a wide opening and allow plenty of air circulation when it boils off. Never seal the opening of a thermos containing liquid Nitrogen. If gas does not escape the container will explode. Common sense safety practices should be used or in some cases, adult supervision.
Liquid Nitrogen Safetyhttps://engineering.dartmouth.edu/microeng/ln2.htmlRecent Superconductor News, Speculativehttp://www.superconductors.org/news.htm
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#4021
by
Space Ghost 1962
on 22 Jul, 2016 22:05
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Saw this placed under the EM drive topic elsewhere online.
Newly discovered material property may lead to high temp superconductivity
http://m.phys.org/news/2016-07-newly-material-property-high-temp.html
Thank you, interesting. In the past we've been able to make microwave sources from CDW.
The way they've fallen apart is due to too much heat destroying the effect, both dimensional stability (it warps) and in losing the effect (here, -53C). But this is better than the -200C from that.
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#4022
by
RERT
on 22 Jul, 2016 23:16
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FL - better if someone else responded: my ignorance of government control of satellite launches is profound. I don't really see why Cannae would be denied permission to launch an experiment with a resonant microwave cavity, but a lot of things don't make sense to me!
I don't know what you mean by 'too slick'. They do seem to care about their website. I can't think of reasons to announce a cube sat thruster with no intention to follow through which don't involve fraud of some kind. Might be a failure of my imagination I guess. Someone - you I think? - seemed to have some contact with the players. Don't you think they plan to follow through? Are they crazy enough to announce this when their (?admired?) test rig shows no thrust?
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#4023
by
JonathanD
on 22 Jul, 2016 23:17
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Well if they actually launch this thing in 24 months (which is a claim worthy of skepticism obviously) then, outright shenanigans aside, it should pretty clearly prove or disprove the ability of the proposd Cannae drive to both move to and maintain this orbit for some period of time, no?
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#4024
by
zen-in
on 22 Jul, 2016 23:41
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Well if they actually launch this thing in 24 months (which is a claim worthy of skepticism obviously) then, outright shenanigans aside, it should pretty clearly prove or disprove the ability of the proposd Cannae drive to both move to and maintain this orbit for some period of time, no?
It is very difficult to distinguish thrust caused by escaping cryogens from the em-drive thrust Cannae hopes to observe. That's why careful ground based tests are needed. I don't know if the Cannae device has been independently tested and proven to work. Like all em-drive experiments there have been a lot of claims that appear to be speculative. I doubt there is any taxpayer money going into this and only time will tell if they are able to launch a device. Just satisfying the flight safety requirements of a launch provider and getting a payload filled with cryogens on the manifest would be an accomplishment by itself. If they can do that in under 3 years I would be very surprised. It might be a lot easier to just drop it off a tall building.
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#4025
by
Monomorphic
on 23 Jul, 2016 01:22
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Build update: Wedge is tuned and ready to go.
I replaced the small end-plate with thicker copper - the same as the big end-plate. I also reinforced the wall on the opposite side of the magnetron, and added the more robust tuning mechanism I referred to in earlier posts. I tune the wedge by manipulating the bolts on the two opposite side-walls seen in the images below. It is very effective.
Center frequency is 2.454Ghz. RL -32dB. Q-factor ~8,000
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#4026
by
Flyby
on 23 Jul, 2016 08:57
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Build update: Wedge is tuned and ready to go.
I replaced the small end-plate with thicker copper - the same as the big end-plate. I also reinforced the wedge on the opposite side of the magnetron, and added the more robust tuning mechanism I referred to in earlier posts. I tune the wedge by manipulating the bolts on the two opposite side-walls seen in the images below. It is very effective.
Center frequency is 2.454Ghz. RL -32dB. Q-factor ~8,000
Your clever use of the bolts reminds me of one of Shawyer's EM drive 2.0 drawings, where he planned on using computer driven Piezo elements on the side walls of his device.
No, i'm not a Shawyer adept, but it does make me wonder to what extend his drawing are " mere imaginary" or are indeed real engineering drawings of a working device...?
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#4027
by
RERT
on 23 Jul, 2016 10:53
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It would be difficult to distinguish between a leak and 100 micro-Newtons of thrust in the short term, but not over 6 months. Even if they leaked 6kg, that's only about 4*10^-7 kg per second over six months. At 100 micro-Newtons, it's being ejected at around 260 metres a second, if I have the arithmetic right. More anecdotally, the idea that a leak might have the same total impulse as an engineered thruster (off the shelf as discussed a few posts back) seems to me implausible.
Essentially, if they can fly this thing for long enough, it is working. I think they have chosen a low orbit to shorten 'long enough'.
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#4028
by
rfmwguy
on 23 Jul, 2016 11:15
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Build update: Wedge is tuned and ready to go.
I replaced the small end-plate with thicker copper - the same as the big end-plate. I also reinforced the wedge on the opposite side of the magnetron, and added the more robust tuning mechanism I referred to in earlier posts. I tune the wedge by manipulating the bolts on the two opposite side-walls seen in the images below. It is very effective.
Center frequency is 2.454Ghz. RL -32dB. Q-factor ~8,000
I always prided myself on using repurposed, unique methods of construction and fabrication...I now bow to a new master
Well done and smart!
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#4029
by
Monomorphic
on 23 Jul, 2016 14:43
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Return Loss (RL) sweep of the wedge from 1.5Ghz to 3Ghz. The mode I am exciting is marked. Notice the RL of -52.46 immediately after 2Ghz... I wonder what mode that is.
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#4030
by
SeeShells
on 23 Jul, 2016 15:21
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Return Loss (RL) sweep of the wedge from 1.5Ghz to 3Ghz. The mode I am exciting is marked. Notice the RL of -52.46 immediately after 2Ghz... I wonder what mode that is.
No time to do the numbers this morning, have an appointment. Although from watching some of my sweeps and if your running a TE013, I'd guess it's a TE012 mode.
Shell
VERY nice build monomorphic!
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#4031
by
Monomorphic
on 23 Jul, 2016 15:35
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Neat picture from the inside showing waveguide launcher and VNA monopole antenna.
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#4032
by
rfmwguy
on 23 Jul, 2016 15:39
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Neat picture from the inside showing waveguide launcher and VNA monopole antenna.
I've built a contraption to polish the inside of the cavity and will test it out tonight. If it works, I'll do a quick video. If it doesn't, I'll delete this post
After several weeks of testing and oxidation, it might be something you'll need down the road.
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#4033
by
WarpTech
on 23 Jul, 2016 16:05
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Neat picture from the inside showing waveguide launcher and VNA monopole antenna.
I've built a contraption to polish the inside of the cavity and will test it out tonight. If it works, I'll do a quick video. If it doesn't, I'll delete this post
After several weeks of testing and oxidation, it might be something you'll need down the road.
I recall using Nox-on metal polish to clean brass and copper. Just rub a light coat of it on the metal. Wait a little while, and wipe it off.
http://www.acehardware.com/product/index.jsp?productId=1418968
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#4034
by
zen-in
on 23 Jul, 2016 18:11
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Neat picture from the inside showing waveguide launcher and VNA monopole antenna.
I've built a contraption to polish the inside of the cavity and will test it out tonight. If it works, I'll do a quick video. If it doesn't, I'll delete this post
After several weeks of testing and oxidation, it might be something you'll need down the road.
One thing that might help is a rouge cloth. They are really meant for Silver but might work for Copper. Your dilemma reminds me of Sir Joseph Porter's song in HMS Pinafore:
When I was a lad I served a term
As office boy to an Attorney's firm.
I cleaned the windows and I swept the floor,
And I polished up the handle of the big front door.
I polished up that handle so carefullee
That now I am the Ruler of the Queen's Navee!
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#4035
by
Monomorphic
on 24 Jul, 2016 02:22
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Vector network analysis when the wedge is cool vs when the wedge is warm. I used a heat gun for several minutes to simulate warming as if via microwave RF. I expected the frequency to drift lower because of thermal expansion, but that was very minimal.
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#4036
by
RotoSequence
on 24 Jul, 2016 03:16
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Vector network analysis when the wedge is cool vs when the wedge is warm. I used a heat gun for several minutes to simulate warming as if via microwave RF. I expected the frequency to drift lower because of thermal expansion, but that was very minimal.
This looks like a great idea for a control test! Any temperatures for the values of hot and cold that were tested?
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#4037
by
RERT
on 24 Jul, 2016 10:39
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Vector network analysis when the wedge is cool vs when the wedge is warm. I used a heat gun for several minutes to simulate warming as if via microwave RF. I expected the frequency to drift lower because of thermal expansion, but that was very minimal.
Great idea, and nice clean data! I notice the charts are auto-scaling: the hot wedge is about 31.15 return loss versus 32.65 for cold. What's that difference translated to Q?
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#4038
by
Monomorphic
on 24 Jul, 2016 12:19
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Vector network analysis when the wedge is cool vs when the wedge is warm. I used a heat gun for several minutes to simulate warming as if via microwave RF. I expected the frequency to drift lower because of thermal expansion, but that was very minimal.
This looks like a great idea for a control test! Any temperatures for the values of hot and cold that were tested?
I didn't record the temperatures. Cold was room temperature, so probably around 75F. Hot was warm to the touch. Next time maybe i'll capture IR images.
Vector network analysis when the wedge is cool vs when the wedge is warm. I used a heat gun for several minutes to simulate warming as if via microwave RF. I expected the frequency to drift lower because of thermal expansion, but that was very minimal.
Great idea, and nice clean data! I notice the charts are auto-scaling: the hot wedge is about 31.15 return loss versus 32.65 for cold. What's that difference translated to Q?
I need to turn off autoscaling - keep forgetting to do that. The difference in Q can be up to 1,500 less. It will be best to perform experiments after the wedge has completely cooled down.
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#4039
by
rfmwguy
on 24 Jul, 2016 17:41
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Well done and smart!
