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#880
by
TheTraveller
on 29 Dec, 2015 10:40
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...Take your time and make sure your surfaces are kept clean, I wore gloves to keep the oils and acids from my hands off the copper.
Shell,
Any chance to see your plans and photos of your magnetron to coax adapter build?
Phil
I'll see what I can do Phil. I have a very busy day, Doctor's appointment this morning and then rebuild my system, have one being delivered this morning to replace the one that just died.
Shell
Thanks Shell. Appreciated.
If not too much trouble, exactly which components & circuit elements failed? Would like to learn so as to not repeat.
Yes I know the big secret that all EEs are sworn to never reveal, well that is until you get too old to uphold the code anymore. Electronics actually works via stored & compressed magic smoke. How do I know this is true? Because when it leaks out, the electronics stops working.
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#881
by
OnlyMe
on 29 Dec, 2015 13:13
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...Take your time and make sure your surfaces are kept clean, I wore gloves to keep the oils and acids from my hands off the copper.
Shell,
Any chance to see your plans and photos of your magnetron to coax adapter build?
Phil
I'll see what I can do Phil. I have a very busy day, Doctor's appointment this morning and then rebuild my system, have one being delivered this morning to replace the one that just died.
Shell
Thanks Shell. Appreciated.
If not too much trouble, exactly which components & circuit elements failed? Would like to learn so as to not repeat.
Yes I know the big secret that all EEs are sworn to never reveal, well that is until you get too old to uphold the code anymore. Electronics actually works via stored & compressed magic smoke. How do I know this is true? Because when it leaks out, the electronics stops working.
TT I believe she was talking about her primary computer that died. She mentioned earlier that she had to work on a laptop because it had died.... I think that's the system she is talking about rebuilding.., recovering the hard drive and hopefully from backups?
I don't think she has gone into detail about the frustum problem beyond that the antenna burnt up. Don't even know if it was one or both. You would need two with two wave guides wouldn't you?
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#882
by
rfmwguy
on 29 Dec, 2015 13:34
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Freebie offer...anyone needing a magnetron to rf connector adapter, I will build one for you. This could be used as a vna probe for a cavity or primary rf injection point. I would recomment sma for vna probe and N, tnc or mini DIN for power applications.
Just need the bad or working magnetron and connector, I'll do the rest. Make sure ceramic BeO on radome is not cracked or discolored/blackened which would be a sign of overheating.
PM me with your request.
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#883
by
oyzw
on 29 Dec, 2015 13:56
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Hello, I am a Chinese Emfans。I am preparing for the experiment，I'm going to do a little EMdrive-boat using 400w microwave solid state source。
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#884
by
DnA915
on 29 Dec, 2015 14:02
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Hey MEEP and EM Experts,
After a small struggle, I just got GSVIT running under our NSF Ubuntu VM under VMBox. Unlike MEEP, this FDTD solver can use GPU's to greatly speed up their solving process. Their own benchmark from their website said that they got an 80x speedup on an unspecified setup, but I suspect that with some of the Amazon instances available, we may see far greater. One nice thing about this is that a GPU is not required to run it so we can set it up in the VM (which is compiled without GPU support). Once its set up, we can move it to a powerful machine to run longer.
Although I have CFD and FDTD programming experience, I have no knowledge of EM simulations. If someone is able to get this set up though so we can compare it to MEEP, then I will pay to do a comparison of speed vs the Amazon machine. At that point, it should be easy to launch an Amazon Image which has all the software ready, run the simulation, upload it to S3 and then shutdown. If this would be a good aid to getting better design, then I'd be willing to do my part and pay for some time.
That being said, I don't want to waste my time. If people don't think that a 100-400x speed up in solving cost would be that beneficial, please just tell me and I'll drop it. Like I said, i don't know EM simulation much so perhaps I've mis-read the current needs of the project.
Here are some links on the project:
http://gsvit.net/index.phphttp://gsvit.net/tutorial/yee.php- David
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#885
by
rfmwguy
on 29 Dec, 2015 14:34
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Hello, I am a Chinese Emfans。I am preparing for the experiment，I'm going to do a little EMdrive-boat using 400w microwave solid state source。
On behalf of this NSF community, welcome to the best forum for emdrive builders, theorists and fans! There is a lot of talent here to help you. You can also take advantage of many here who can describe best practices in testing. I can help a little, but there are many more here with scientific credentials far better than mine.
Please keep us informed as your project progresses.
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#886
by
TheTraveller
on 29 Dec, 2015 15:02
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Hello, I am a Chinese Emfans。I am preparing for the experiment，I'm going to do a little EMdrive-boat using 400w microwave solid state source。
Welcome to the DIY EmDrive build club.
If I may ask what are your interior dimensions & build material?
400W is a large Rf amp. For my build I'm using a 100W unit. Do you have a link for your amp?
There may be a better coupler to excite TE013 mode than you are showing. It mounts on the middle of the big end plate. If interested I have several papers on this coupler. See attached.
One comment is your rtn loss peak looks to be low. You may need to look at improving your rtn loss peak to improve VSWR and reduce reflected Rf from your frustum.
Good luck
Phil
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#887
by
graybeardsyseng
on 29 Dec, 2015 16:44
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Hello -
Sorry I have been away for a while - serious family medical issues (more about that later) and I am binge reading the EM Drive forum. In doing some searching for UHF RF amps I found the following on eBay. I haven't seen these mentioned on the forum so I thought I would throw this out. Below is just one link - the vendor has quite a few different combinations. Basically these are 2.3 Ghz linear RF amplifiers boards removed from Spectrian RF amps which output up to about 75-80w depending on drive. At 2.45 they are a few dB down and can generate about 40w - although EM Drive DUTs could easily be sized for 2.3 Ghz. (see TheTraveller's wonderful spreadsheet). This unit is right about $100.
http://www.ebay.com/itm/221972679316?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AITAnyway as mentioned these are
LINEAR and can be used either a amps for a CW signal or modulated with various schemes (AM, SSB etc) if desired. There are complete RF units available which can get up to about 180+w paralleling outputs. That unit is about $350. The vendor has a fair amount of data on his eBay page and provides enough info for further google mining.
Hope this is helpful!
Happy New Year to All - Herman
PS.
Shell - CONGRATS on results!!!!!!!! Looking forward to more data. You are the gold standard we are all watching! It is so rewarding to see what careful engineering can do. I agree with a post somewhere back a few pages - I think you must have a third arm and a few dozen Watchmakers.
Phil (TT) - glad to hear the good medical news! and as someone trying to clean out years of stored debris from my garage workshop I appreciate your situation there too. Looking forward to your build this year.
rfmwguy - Dave - contgrats on your Moderatorship and all hail the Guardian of the Forum and looking forward to NSF-1701 part Deux.
EDIT - Spelling correction - ready to reading.
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#888
by
Chrochne
on 29 Dec, 2015 17:22
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Hello, I am a Chinese Emfans。I am preparing for the experiment，I'm going to do a little EMdrive-boat using 400w microwave solid state source。
Welcome to the forum. If you know more people from China that are working on their own EmDrive please bring them here. We can resolve this mystery here together - with worldwide effort and knowledge. Sort of International space station for EmDrive community.
To all other folks: If I remember correctly we had some texts from chinese professor that was testing the EmDrive. Perhaps our friends from China can now help us in case we do not understand something from her research papers.
I feel we really may solve this issue in 2016 or at least bring us closer to better understanding.
Modification: Little update. I have small reply from Kroean video EmDrive tester. Not exactly the guy himself, but this person speak Korean. We are trying to contact those folks now and bring them here.
Modification number 2: If you guys plan to bring new folks here also refer to them the EmDrive Wiki so we can avoid repeating questions and ease some pain to the folks like Dr.Rodal, Aero and many others who kindly reply to these questions.
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#889
by
RFPlumber
on 29 Dec, 2015 17:47
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Hello -
Sorry I have been away for a while - serious family medical issues (more about that later) and I am binge reading the EM Drive forum. In doing some searching for UHF RF amps I found the following on eBay. I haven't seen these mentioned on the forum so I thought I would throw this out. Below is just one link - the vendor has quite a few different combinations. Basically these are 2.3 Ghz linear RF amplifiers boards removed from Spectrian RF amps which output up to about 75-80w depending on drive. At 2.45 they are a few dB down and can generate about 40w - although EM Drive DUTs could easily be sized for 2.3 Ghz. (see TheTraveller's wonderful spreadsheet). This unit is right about $100.
http://www.ebay.com/itm/221972679316?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Anyway as mentioned these are LINEAR and can be used either a amps for a CW signal or modulated with various schemes (AM, SSB etc) if desired. There are complete RF units available which can get up to about 180+w paralleling outputs. That unit is about $350. The vendor has a fair amount of data on his eBay page and provides enough info for further google mining.
Hope this is helpful!
Happy New Year to All - Herman
PS.
Shell - CONGRATS on results!!!!!!!! Looking forward to more data. You are the gold standard we are all watching! It is so rewarding to see what careful engineering can do. I agree with a post somewhere back a few pages - I think you must have a third arm and a few dozen Watchmakers.
Phil (TT) - glad to hear the good medical news! and as someone trying to clean out years of stored debris from my garage workshop I appreciate your situation there too. Looking forward to your build this year.
rfmwguy - Dave - contgrats on your Moderatorship and all hail the Guardian of the Forum and looking forward to NSF-1701 part Deux.
EDIT - Spelling correction - ready to reading.
Yes, I'm using the 35W one from this guy. Note a couple of things:
1. The 35W is more of an "amplifier" as it delivers 30W output from as low as 7 dBm input. The 75W one requires about 2W on input to deliver those 75W.
2. The 75W one takes 20A(!) from its power source.
3. These produce peak output in the 2.30-2.35 GHz range. Outside the range for the 30W amp I am getting these numbers:
=========== 30 W Amplifier Max Pwr vs Freq ============
Mhz:
2200: 4.3W
2250: 13W
2300: 30W
2350: 28W
2400: 21W
2450: 12W
2500: 4.5W
===================
Other than that, these are the cheapest choices out there. The next option would appear to be using evaluation boards for some of the new power RF MOSFETs. Many / most of these
http://www.wolfspeed.com/rf/products/general-purpose-broadband-28-v/table have evaluation boards which could be used as a amp (within the freq range they intended for the particular board. They are not exactly wide band either). Boards are typically priced around $500 though.
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#890
by
RFPlumber
on 29 Dec, 2015 17:56
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Hello, I am a Chinese Emfans。I am preparing for the experiment，I'm going to do a little EMdrive-boat using 400w microwave solid state source。
Welcome! Have fun building. Keep in mind though that the most likely outcome to expect is that this "drive" will not produce any
drive thrust...
What is your 400W RF source? How are you planning to control its frequency to stay within the resonance range of the cavity? Given the amount of dissipated heat, copper thermal expansion coefficient, expected Q factor and sensitivity of the resonance freq of this geometry to its size, it will take about 2-4 seconds at 400W for the cavity to expand out of resonance. (I have calculated it for my 30W fixed freq input, and I am lucky to have 10-20 seconds of working time).
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#891
by
rfmwguy
on 29 Dec, 2015 18:13
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welcome back herman, hope health issues are behind you. a couple of new diy efforts internationally as you can see. shell is rebuilding injection scheme as power fried an antenna. she didnt tell me her results but got a feeling nsf-1701 will be in the slow lane knowing her skills.
phil does have his own group and you should join...interesting archival stuff. he'll probably send you an invite...by invitation only...not a bad idea to have archives off nsf for easier access.
finally got this laptop talking at higher speed to the spreadsheet, in fact its near real time as of a few minutes ago...far more that I need for the LDC/ ADC to measure beam typical displacement. People want more data next year on Phase II tests? I'll have it and then some. about 2.4K points in Phase I will go to about 64K points per test run(s).
Now using screen recorder software, far better than hokey vid cam. I still shoot vid of entire test rig along with screen record. Only needed a faster pc to be able to utilize...quad core stuff and lots of ram.
Getting a solid brass frustum from a musical instrument brassmith cut to my original nsf-1701 dimensions in a couple of weeks, vna testing after that.
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#892
by
rfmwguy
on 29 Dec, 2015 20:01
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Wireless temp/humidity datalogger. Uses thermocouple probes. Probably will get this for next round od tests:
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#893
by
zen-in
on 29 Dec, 2015 22:35
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W.r.t. building the cavity... Cutting the template out of sheet copper is easy, but then making the actual frustum out of it - not so much. In fact I am still trying to find out a way... The next attempt is going to be with a "jig" made from 2 wood boards with pre-routed paths for both the big and the small sides...
Or is it all because my copper is C110 and not the O2 free? Would the latter be much more pliable and hence easier to make into a frustum?
I bought a 900 x 900 x 0.5mm (0.020") sheet of C110 that was rated as "soft". There are 2 harder variants of C110 available.
...
Plan to use these hoops on the inside and outside of the cone while forming to keep things circular and in place. 1.5" to 18" dia available.
...
Will leave 3 hoops epoxied on the outside, as attached, for additional rigidity as the cone is only 0.5mm (0.020") thick.
Soft Copper will work harden so the trick is to minimize the bending. Using a 1 foot Dia piece of PVC pipe or a small bucket. it should be easy to just bend the whole thing into a cylinder shape. If you thought ahead before cutting and have tabs on the end those tabs should be bent so you can lock the cone shape in place. The natural springiness of the Copper, after being bent, should be enough to keep it in a smooth cone shape. Don't cut any tabs on the top or bottom until after the cone shape is set.
Another option is to use a sheet metal roller. That will but a curve in the metal. If the roller is adjusted so one side is biased the cone shape should come out of the roller. Then you have the problem of removing the Copper without distorting it.
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#894
by
graybeardsyseng
on 29 Dec, 2015 23:37
-
Hello -
Sorry I have been away for a while - serious family medical issues (more about that later) and I am binge reading the EM Drive forum. In doing some searching for UHF RF amps I found the following on eBay. I haven't seen these mentioned on the forum so I thought I would throw this out. Below is just one link - the vendor has quite a few different combinations. Basically these are 2.3 Ghz linear RF amplifiers boards removed from Spectrian RF amps which output up to about 75-80w depending on drive. At 2.45 they are a few dB down and can generate about 40w - although EM Drive DUTs could easily be sized for 2.3 Ghz. (see TheTraveller's wonderful spreadsheet). This unit is right about $100.
http://www.ebay.com/itm/221972679316?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Anyway as mentioned these are LINEAR and can be used either a amps for a CW signal or modulated with various schemes (AM, SSB etc) if desired. There are complete RF units available which can get up to about 180+w paralleling outputs. That unit is about $350. The vendor has a fair amount of data on his eBay page and provides enough info for further google mining.
Hope this is helpful!
Happy New Year to All - Herman
PS.
Shell - CONGRATS on results!!!!!!!! Looking forward to more data. You are the gold standard we are all watching! It is so rewarding to see what careful engineering can do. I agree with a post somewhere back a few pages - I think you must have a third arm and a few dozen Watchmakers.
Phil (TT) - glad to hear the good medical news! and as someone trying to clean out years of stored debris from my garage workshop I appreciate your situation there too. Looking forward to your build this year.
rfmwguy - Dave - contgrats on your Moderatorship and all hail the Guardian of the Forum and looking forward to NSF-1701 part Deux.
EDIT - Spelling correction - ready to reading.
Yes, I'm using the 35W one from this guy. Note a couple of things:
1. The 35W is more of an "amplifier" as it delivers 30W output from as low as 7 dBm input. The 75W one requires about 2W on input to deliver those 75W.
2. The 75W one takes 20A(!) from its power source.
3. These produce peak output in the 2.30-2.35 GHz range. Outside the range for the 30W amp I am getting these numbers:
=========== 30 W Amplifier Max Pwr vs Freq ============
Mhz:
2200: 4.3W
2250: 13W
2300: 30W
2350: 28W
2400: 21W
2450: 12W
2500: 4.5W
===================
Other than that, these are the cheapest choices out there. The next option would appear to be using evaluation boards for some of the new power RF MOSFETs. Many / most of these http://www.wolfspeed.com/rf/products/general-purpose-broadband-28-v/table have evaluation boards which could be used as a amp (within the freq range they intended for the particular board. They are not exactly wide band either). Boards are typically priced around $500 though.
rfplumber -
Thanks! Great input. I am a bit surprised by how low the efficiency is - seems to work out about 17 % which is low for even class A or class AB amps. And 2watts of drive is not trivial . From what I have been able to gather they (Spectrian) seems to be operating in a push pull configuration with a pretty aggressive (Read Narrow output bandpass filter which would account for the rapid power roll off when operated off design.
Hams seem to have good luck using these things for 13 cm band operations - there are quite a few sources around the net. In particular they use them for moonbounce work (which is a really esoteric corner of amateur radio ; want to bounce your voice of the moon?) and in doing so they have built up a fairly extensive body of knowledge of how to use them. A couple of links are:
http://www.w6pql.com/120w_13_cm_amplifier.htmhttp://www.qslnet.de/member/on4iy/spectrian.htmlSome general info.
http://www.ntms.org/files/eme_mud07%5B1%5D.pdf Starting at about slide 18. Note - this is a very moonbounce centric paper with a LOT of off topic material but there is some good stuff on the need for real time monitoring of these amps to keep the magic smoke inside.
Final Comment - I know most everyone is aware of this - certainly rfplumber, rfwmguy, shell , TT and others are , but for anyone contemplating working with these or other high power RF devices remember - SAFETY FIRST LAST AND ALWAYS. High power DC and RF can be deadly.
Herman - W5HLP
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#895
by
SeeShells
on 30 Dec, 2015 00:27
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Hello, I am a Chinese Emfans。I am preparing for the experiment，I'm going to do a little EMdrive-boat using 400w microwave solid state source。
Welcome from another builder of a EMDrive. This is a great place to gain information and exchange ideas.
Shell
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#896
by
SeeShells
on 30 Dec, 2015 00:39
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Still getting my systems back up, hours of work still to go but TT and rfmwguy wanted to see my blown
ack! Silly upgrading ... sorry .
Shell
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#897
by
rfmwguy
on 30 Dec, 2015 00:49
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Still getting my systems back up, hours of work still to go but TT and rfmwguy wanted to see my blown
Uhhh, methinks you need to finish that sentence shell....
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#898
by
aero
on 30 Dec, 2015 01:14
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Still getting my systems back up, hours of work still to go but TT and rfmwguy wanted to see my blown
Uhhh, methinks you need to finish that sentence shell....
I would like to see a picture of her blown antenna ...
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#899
by
rfmwguy
on 30 Dec, 2015 01:21
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Still getting my systems back up, hours of work still to go but TT and rfmwguy wanted to see my blown
Uhhh, methinks you need to finish that sentence shell....
I would like to see a picture of her blown antenna ...
To each their own I suppose...
Actually, I asked her for it as well. Did see the mag to N transition pic...center conductor was matchstick as she described. One of the frustum antennas gave way and that imbalance wrecked the source transition.
this complexity is why I put the mag on the frustum. This type of power and balance is verrrry tricky...she's a great engineer and will solve it tho...
