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#1280 by Tellmeagain on 15 Apr, 2016 15:51
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Thank you for further clarification (not clear whether you are dismissing all Cannae's measurements or just NASA's measurements of Cannae's device):
Do you take more seriously Cannae's claimed force measurements with the grooves? while NASA's measurements showed no anomalous force effect with Cannae's grooves?
Do you take more seriously Cannae's claimed force measurements with the Cannae non-superconducting and superconducting devices rather than NASA's measurements using a torque pendulum?
If so, what is the basis for taking Cannae's measurements more seriously than NASA's measurements?
I was dismissing NASA's measurements because I think I know what they did incorrectly. I do not know Cannie's experiments as they are not published.
No, I do not take Cannie's claims seriously because I do not believe the EmDrive concept is valid. I think if I can have the chance to observe Cannie's experiment closely, I can spot what is done incorrectly. -
#1281 by Rodal on 15 Apr, 2016 15:52
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Anyone else see the problem with using these with a magnetron? Hint, look at temp. Without proper thermal isolation, the 200 deg C/392 deg F can be a problem if dielectric is close to mag heat sink.Rigid HDPE Polyethylene Rod, 6" Diameter
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McMaster is located here in Atlanta. How convenient! I think NASA used two of the 6" diameter 1" length discs that run $18.54 each: http://www.mcmaster.com/#hdpe/=11zr8dk
I do not think I can get a 6" disc through the small end opening of my frustum, so I may have to go with the 4 or 5 inch. Does this stuff bend or is it very rigid like resin? If i can double it over I won't have to cut each disk in half.
1) Did you mean to write "magnetron heat source" instead of "mag heat sink" ?
The magnetron in that case is not a heat sink. It is the complete opposite: a heat source
2) Yes, HDPE can be exposed to 120 °C/ 248 °F for short periods of time. Have to use thermal scan camera to make sure that at location of dielectric insert this temperature is not exceeded
HDPE has a (very weak) glass transition temperature at around 110 to 120 °C (see attachment)
Temperature of the dielectric should preferably be below 110 °C /230 °F.
NOTE: Some very interesting effects take place at the Tg ( 110 °C /230 °F). For example regarding the frequent discussions of group velocity and phase velocity. The readers have to take into account that the electric permittivity behavior is not only a strong function of temperature, but a strong funtion of frequency, and that at 2.4 GHz, the behavior is tantamount to operating at a much lower temperature per the well-known WLF equation and time-temperature superposition
3) Suggest to place the magnetron and the dielectric insert at opposite ends and to monitor with thermal camera (taking into account the emissiivity of the radiating body).
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#1282 by rfmwguy on 15 Apr, 2016 16:06
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A magnetron is the heat source and the dielectric should not be mounted anywhere near where it's heat is conducted or "sunk"; as in the plate/sidewall its mounted on. In that case that plate/side is a heat sink.
Anyone else see the problem with using these with a magnetron? Hint, look at temp. Without proper thermal isolation, the 200 deg C/392 deg F can be a problem if dielectric is close to mag heat sink.Rigid HDPE Polyethylene Rod, 6" Diameter
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McMaster is located here in Atlanta. How convenient! I think NASA used two of the 6" diameter 1" length discs that run $18.54 each: http://www.mcmaster.com/#hdpe/=11zr8dk
I do not think I can get a 6" disc through the small end opening of my frustum, so I may have to go with the 4 or 5 inch. Does this stuff bend or is it very rigid like resin? If i can double it over I won't have to cut each disk in half.
1) Did you mean to write "magnetron heat source" instead of "mag heat sink" ?
The magnetron in that case is not a heat sink. It is the complete opposite: a heat source
2) Yes, HDPE can be exposed to 120 °C/ 248 °F for short periods of time. Have to use thermal scan camera to make sure that at location of dielectric insert this temperature is not exceeded
3) Suggest to place the magnetron and the dielectric insert at opposite ends and to monitor with thermal camera (taking into account the emissiivity of the radiating body).
I would not recommend its use with a mag, as the copper frustum will eventually conduct heat throughout if on for any length of time. I believe this was the cause of some of EWs melted screws in their early testing with a magnetron.
If insistent or experimenting, use ceramic standoffs and figure a way to mount it without hardware that will conduct heat. Nylon screws will melt, metallic screws will conduct. A mag pushes dielectrics to the extreme. Lower power...not so much. Of course, ceramic standoffs will contribute to the dielectric properties. -
#1283 by SteveD on 15 Apr, 2016 16:09
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Among all these posts about Cannae's website it is useful to remember that, since this is NASA Spaceflight.com , after alll:
1) NASA's testing of Cannae's drive that resulted in a measurable anomalous force needed the presence of a dielectric insert in the pipe connecting to the flying-saucer shaped device. There was no thrust measured by NASA without a dielectric insert in the Cannae drive.
2) NASA's computer modeling of the electric field within the pillbox and beam pipe (using COMSOL Multiphysics® software) illustrates the relative weakness of the electric field in the vicinity of the cavity slots and relative strength of the electric field within the beam pipe, especially in the drive antenna coaxial cable and the region around the cable. NASA's COMSOL analysis shows that the important part is not the flying saucer shape of the Cannae drive, but it is instead the small diameter pipe (where the dielectric insert is contained) connecting to the center of the flying-saucer shape cavity.
3) Guido Fetta's new World Patent (World Intellectual Property Organization) application Electromagnetic thrusting system WO 2016004044 A1 (Filing date Jun 30, 2015) http://www.google.com/patents/WO2016004044A1?cl=en explicitly includes a dielectric in its claims, starting with claim 1:Quotethe waveguide including a dielectric material positioned to extend in a direction of the wave axis along a portion of the waveguide
while his original US patent application Electromagnetic thruster US 20140013724 A1 (Filing date Mar 22, 2012) did not contain a reference to a dielectric insert. This inclusion of the dielectric in the patent claims follows NASA's 2014 report:
Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum
David A. Brady*, Harold G. White†, Paul March‡, James T. Lawrence§, and Frank J. Davies
Joint Propulsion Conference
July 28-30, 2014, Cleveland, OH
AIAA 2014-4029
This material was declared a work of the U.S. Government and is not subject to copyright protection in the United States.
50th AIAA/ASME/SAE/ASEE Propulsion and Energy Forum
You know me by now, looking at thing a little differently and I'm looking at this differently as well.
If we are to consider the the energy within this cavity where the highest levels exist you're correct, it's in the spindle section versus the pancake section, although I would like you to consider the total amount of energy present for a the given volumes in the spindle and the pancake.
A very rough calculation is showing that >150 times greater energy levels exists per volume in the area of the pancake section versus the spindle, even though you do have a peak in the spindle area.
Food for thought.
Shell
You know, I had an idea about why this thing worked last thread that nobody liked but might be applicable. The rf bounces between two points taking the shortest 3 dimensional path. The acceleration though has to follow the shell of the device. Both propagate at the speed of light. A pancake shape means a very quick transit between the two reflective points while maximizing the area that the acceleration has to propagate through. The acceleration is still light lagged (isn't in the light cone of the reflector) when the reflection takes place. If KE=1/2mv^2 then, if both endplates are at a constant speed (say 10m/s and 10m/s) the endplate in the direction of motion will gain more KE then the opposite endplate will lose (unless the acceleration has reached the opposite point of reflection in which case the equation will balance).
I suppose I could be very wrong in treating acceleration in the same way I would an electrical charge propagating through the shell of the device. Still, if correct it would explain why a superconducting pancake with the bulk of its energy in the very center works (assuming it actually does work). -
#1284 by Rodal on 15 Apr, 2016 16:22
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1) One should not confuse "melting temperature" with the "glass transition temperature". They are completely different temperatures and material behavior. There is no evidence that the HDPE dielectric used in NASA's analysis reached the melting temperature of extruded HDPE (180 °C (356 °F)). Also what you call "melting of Nylon bolts" may not be the proper terminology, as what happened may have been that the heat deflection temperature was exceeded (instead of the Nylon bolts melting into a viscous liquid).
A magnetron is the heat source and the dielectric should not be mounted anywhere near where it's heat is conducted or "sunk"; as in the plate/sidewall its mounted on. In that case that plate/side is a heat sink.
Anyone else see the problem with using these with a magnetron? Hint, look at temp. Without proper thermal isolation, the 200 deg C/392 deg F can be a problem if dielectric is close to mag heat sink.Rigid HDPE Polyethylene Rod, 6" Diameter
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McMaster is located here in Atlanta. How convenient! I think NASA used two of the 6" diameter 1" length discs that run $18.54 each: http://www.mcmaster.com/#hdpe/=11zr8dk
I do not think I can get a 6" disc through the small end opening of my frustum, so I may have to go with the 4 or 5 inch. Does this stuff bend or is it very rigid like resin? If i can double it over I won't have to cut each disk in half.
1) Did you mean to write "magnetron heat source" instead of "mag heat sink" ?
The magnetron in that case is not a heat sink. It is the complete opposite: a heat source
2) Yes, HDPE can be exposed to 120 °C/ 248 °F for short periods of time. Have to use thermal scan camera to make sure that at location of dielectric insert this temperature is not exceeded
3) Suggest to place the magnetron and the dielectric insert at opposite ends and to monitor with thermal camera (taking into account the emissiivity of the radiating body).
I would not recommend its use with a mag, as the copper frustum will eventually conduct heat throughout if on for any length of time. I believe this was the cause of some of EWs melted screws in their early testing with a magnetron.
If insistent or experimenting, use ceramic standoffs and figure a way to mount it without hardware that will conduct heat. Nylon screws will melt, metallic screws will conduct. A mag pushes dielectrics to the extreme. Lower power...not so much. Of course, ceramic standoffs will contribute to the dielectric properties.
2) You are assuming, without analysis, that if the dielectric used by NASA reached or exceeded temperatures close to the Tg of HDPE, that would be something bad.
On the contrary, the behavior observed by NASA may have taken place precisely because the dielectrics used experienced temperatures near the Tg, where interesting nonlinear material effects are known to take place including group velocity, reflectivity and refraction, that cannot be described simply by a constant electric permittivity
3) In this analysis one should not ignore that the epsilon prime and epsilon double prime are strong functions of frequency as well as temperature, and that frequency is 2.4 GHz (instead of low frequency behavior). -
#1285 by zen-in on 15 Apr, 2016 16:23
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Anyone else see the problem with using these with a magnetron? Hint, look at temp. Without proper thermal isolation, the 200 deg C/392 deg F can be a problem if dielectric is close to mag heat sink.Rigid HDPE Polyethylene Rod, 6" Diameter
More About Plastics
Length, ft.
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McMaster is located here in Atlanta. How convenient! I think NASA used two of the 6" diameter 1" length discs that run $18.54 each: http://www.mcmaster.com/#hdpe/=11zr8dk
I do not think I can get a 6" disc through the small end opening of my frustum, so I may have to go with the 4 or 5 inch. Does this stuff bend or is it very rigid like resin? If i can double it over I won't have to cut each disk in half.
You can always get that 6" dia. piece turned down to size with a lathe. A ham radio enthusiast I know told me he always tests the suitability of any plastic he uses by putting it in a microwave oven at high power for 5 Min. If it comes out heated the plastic is lossey so he doesn't use it. I don't know if HDPE is lossey but if it heats up in a microwave it will definitely heat up in your Copper cone; reducing the Q a lot. -
#1286 by Rodal on 15 Apr, 2016 16:26
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Anyone else see the problem with using these with a magnetron? Hint, look at temp. Without proper thermal isolation, the 200 deg C/392 deg F can be a problem if dielectric is close to mag heat sink.Rigid HDPE Polyethylene Rod, 6" Diameter
More About Plastics
Length, ft.
1
Each
ADD TO ORDER
In stock
$70.39 Each
McMaster is located here in Atlanta. How convenient! I think NASA used two of the 6" diameter 1" length discs that run $18.54 each: http://www.mcmaster.com/#hdpe/=11zr8dk
I do not think I can get a 6" disc through the small end opening of my frustum, so I may have to go with the 4 or 5 inch. Does this stuff bend or is it very rigid like resin? If i can double it over I won't have to cut each disk in half.
You can always get that 6" dia. piece turned down to size with a lathe. A ham radio enthusiast I know told me he always tests the suitability of any plastic he uses by putting it in a microwave oven at high power for 5 Min. If it comes out heated the plastic is lossey so he doesn't use it. I don't know if HDPE is lossey but if it heats up in a microwave it will definitely heat up in your Copper cone; reducing the Q a lot.
HDPE has low tan delta: 0.00031 @ 3 GHz
It can be measured with Dielectrometry equipment (Perkin Elmer, etc.)
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#1287 by SeeShells on 15 Apr, 2016 16:36
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It is also appropriate to consider the following experimental results and patents in such a review:
Dr, Rodal,
It maybe appropriate to review this as it's interesting that three things are apparent.
1. Vastly different drive shapes and configurations and both reported thrust.
2. Neither reported using dielectrics.
3. One was superconducting and the other not.
Shell
How should we interpret/analyze the reported experimental result that NASA only measured anomalous thrust for the Cannae non-superconducting device when introducing a dielectric insert in the Cannae pipe ?
And the fact that Cannae, after NASA's 2014 measurement, incorporated a dielectric in Cannae's 2015 patent claims?
How can it be explained the reported testing with thrusts without dielectrics?
Also
It's unclear if EW inserted a PTFE "slug" into the cavity or the Slug was the area surrounding the coax inner conductor from the paper. I don't see in the report where they tested the Cannae device with out the PTFE slug.
<quote>
Figure 8. Slotted Pillbox Cavity (view down beam pipe central axis) and Test Article Close-up
Downloaded by Philip Panicker on August 2, 2014 | http://arc.aiaa.org | DOI: 10.2514/6.2014-4029
American Institute of Aeronautics and Astronautics 7
pipe central axis rotated 180 degrees) orientation. An amplified RF signal is fed into one of the test article beam pipes via an approximately 20-gauge copper wire drive antenna. On the opposite beam pipe, an approximately 20gauge copper wire serves as a sense antenna that provides the cavity RF signal frequency so the Test Engineer can manually adjust the RF frequency input to maintain the cavity resonant frequency during a test run. Cavity resonant frequency is determined during a pre-test cavity evaluation using a vector network analyzer (VNA). In addition, beam pipe extensions were added and held in place by adhesive copper tape, electrical tape, and nylon tie wraps as needed to position the drive and sense antennas, in order to manage (or measure) the electric and magnetic fields in the beam pipe and the pillbox. Figure 9 shows a test article mounted on the torsion pendulum during a test campaign, and a test block diagram follows. The longer beam pipe is the RF drive antenna that in practice ends up being a ¼ wave resonance system in its own right and has a dielectric PTFE slug in the throat in both the slotted and null test article. It is this characteristic that became an item of further consideration after completion of the test campaign.
<quote>
E. COMSOL Multiphysics® Analysis of Cannae Cavities Computer modeling of the electric field within the pillbox and beam pipe (using COMSOL Multiphysics® software, hereafter referred to as “COMSOL®”) illustrates the relative weakness of the electric field in the vicinity of the cavity slots and relative strength of the electric field within the beam pipe, especially in the drive antenna coaxial cable and the region around the cable within the PFTE dielectric slug as seen in Fig. 14. Consideration of the dynamic fields in the ¼ wave resonance tube shows that there is always a net Poynting vector meaning that the RF launcher tube assembly with dielectric cylinder common to both the slotted and smooth test articles is potentially a Q-thruster where the pillbox is simply a matching network.
<quote>
The resistive RF Load evaluation indicated no significant systemic cause for torsion pendulum displacement. Based upon this observation, both test articles (slotted and unslotted) produced significant thrust in both orientations (forward and reverse). Test schedule constraints prevented multiple data points to be gathered in the reverse orientation, and the single data point for each test article is insufficient to allow comparative conclusions (between slotted and unslotted) to be drawn. However, for the forward thrust orientation, the difference in mean thrust between the slotted and unslotted was less than two percent. Thrust production was not dependent upon the slotting.
<End Quotes>
Do you have information that's not in this report concerning the PTFE inserts and how EW conducted these test?
Shell -
#1288 by Monomorphic on 15 Apr, 2016 16:37
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Whoops! Made a huge mistake on the first thermal static test. The makeshift holder I created to fit the camera to my tripod was covering the IR sensor. So all we were seeing is the temperature of the metal blocking the sensor with an image overlay. I have deleted that post and video from youtube. This is a thermal static test with proper IR information.
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#1289 by Rodal on 15 Apr, 2016 16:41
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...
The factual information I have in this regards is that:
Do you have information that's not in this report concerning the PTFE inserts and how EW conducted these test?
Shell
1) All NASA tests of the Cannae device showing an anomalous force were conducted with a dielectric insert in the Cannae pipe. The above quotation confirms this.
2) Cannae's 2012 US patent did not include dielectric inserts. Cannae 2015 patent, filed after NASA's 2014 reported Cannae tests with a dielectric, involves dielectric insert starting with claim #1.
3) NASA's tests with and without a dielectric the truncated cone of Shawyer, also tested by Yang, and measured no significant anomalous force without a dielectric even when increasing the power by a factor exceeding 10 times.
Further than that, rather than working from memory, I will have to review previous threads discussions between NSF members like Star-Drive regarding these tests, particularly information regarding testing with different dielectric materials.
PS: Thanks for reminding me that NASA used Teflon (PTFE) dielectric for the Cannae frustum -
#1290 by rfmwguy on 15 Apr, 2016 16:41
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Whoops! Made a huge mistake on the first thermal static test. The makeshift holder I created to fit the camera to my tripod was covering the IR sensor. So all we were seeing is the temperature of the metal blocking the sensor with an image overlay. I have deleted that post and video from youtube. This is a thermal static test with proper IR information.
That's a bit better...for commonality, you might want to switch to degrees C. Lower temp could indicate a better match, but seems yours is running cooler than mine. Here is my thermal vid for reference. (enjoy the tune):
p.s. You're firing up at close to 1 kW, PLEASE be sure you have your microwave leak detector near you while she's warming up. No Rad is good Rad.
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#1291 by SteveD on 15 Apr, 2016 16:56
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Whoops! Made a huge mistake on the first thermal static test. The makeshift holder I created to fit the camera to my tripod was covering the IR sensor. So all we were seeing is the temperature of the metal blocking the sensor with an image overlay. I have deleted that post and video from youtube. This is a thermal static test with proper IR information.
Hum. I don't see any evidence of a mode shape and the frustum does not seem to be heating. Mag is very hot though. Hate to say it but I don't think the rf is getting into the device. Time to tune. -
#1292 by rfmwguy on 15 Apr, 2016 16:59
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He is using direct side injection, RF is in the cavity. Mag is not overtemp, so no tremendous mismatch I believe. Frustum temp is not a good predictor of mode, as copper conducts heat very quickly and will wash-out most hot spots from my experience.Whoops! Made a huge mistake on the first thermal static test. The makeshift holder I created to fit the camera to my tripod was covering the IR sensor. So all we were seeing is the temperature of the metal blocking the sensor with an image overlay. I have deleted that post and video from youtube. This is a thermal static test with proper IR information.
Hum. I don't see any evidence of a mode shape and the frustum does not seem to be heating. Mag is very hot though. Hate to say it but I don't think the rf is getting into the device. Time to tune. -
#1293 by Rodal on 15 Apr, 2016 17:03
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Whoops! Made a huge mistake on the first thermal static test. The makeshift holder I created to fit the camera to my tripod was covering the IR sensor. So all we were seeing is the temperature of the metal blocking the sensor with an image overlay. I have deleted that post and video from youtube. This is a thermal static test with proper IR information.
Hum. I don't see any evidence of a mode shape and the frustum does not seem to be heating. Mag is very hot though. Hate to say it but I don't think the rf is getting into the device. Time to tune.
Most mode shapes are most visible and identifiable on the circular cross-section rather than the side walls. (This is because the the gradients are higher in the cross-section than in the longitudinal direction for these low order mode shapes).
The small end cannot show anything because the induction heated small end is several inches away from the visible small end, therefore there is no induction heating on the visible small end (because this frustum has an extended section of constant circular cross-section actuated by screws to change the internal length of the cavity).
Must focus on the circular big end (which is not visible in this view) to look for the mode shape (if and only if there is a resonance) -
#1294 by Eusa on 15 Apr, 2016 17:04
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As I think an anisotropic electricity is harmful to gravitational flux warping. The dielectric material can reduce those interferences.
In this cross-section I explore if it's possibe to use semipermeable smaller reflector instead of perforated...
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#1295 by Monomorphic on 15 Apr, 2016 17:23
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Hum. I don't see any evidence of a mode shape and the frustum does not seem to be heating. Mag is very hot though. Hate to say it but I don't think the rf is getting into the device. Time to tune.
The frustum heats from 70.2 to 72.5. -
#1296 by Monomorphic on 15 Apr, 2016 17:36
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It's hard to make out without analyzing the frames separately. This frustum is tuned to TE311. That should leave a resonance pattern on the side walls towards the big end as shown in the FEKO sim below. I think i'm seeing more heating towards the big end in the IR video...
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#1297 by Monomorphic on 15 Apr, 2016 18:08
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How about giving us a thermal view of the big end, with the camera focus perpendicular to the center of the big end, showing only the big end, when you have a chance?
Here you go, but as the magnetron gets hot it swamps everything out. Will need to orient the camera so the magnetron can't be seen.
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#1298 by rfmwguy on 15 Apr, 2016 18:42
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Covering the outside surface with standard thermal paper will start making it dark around 150 deg F. Doesn't look like frustum is getting there.
Peep-hole paper in front of flir lets you focus on endplate without having to move the flir in too close.
I'd recommend this and set your Flir to variable target, which crosshair will chase hotspot. Not convinced copper will let you "see" modes due to quick thermal dispersion, but does not hurt to try. -
#1299 by Rodal on 15 Apr, 2016 18:47
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How about giving us a thermal view of the big end, with the camera focus perpendicular to the center of the big end, showing only the big end, when you have a chance?
Here you go, but as the magnetron gets hot it swamps everything out. Will need to orient the camera so the magnetron can't be seen.
I'm not sure if this is what rfmwguy is referring to, but I also would like to have the magnetron covered so that the thermal camera cannot see the magnetron or see anything hotter than the big end. As you say, the magnetron is so much hotter that the small difference in temperature ( of the order of a few deg F: 72 deg F is only 4 deg F above room temperature of 68 deg F ?) will not be visible
What is the deg F resolution possible with this camera?
At the moment, the color scheme is showing the hot magnetron which is much hotter, over 200 deg F, and therefore the mode shape small delta T will not show. Have to hide the magnetron from view