proper way to make a magnetron tube to waveguide adapter?

[coppercone2]

So another one of my microwaves has died, and I acquired another magnetron.

I have built a magnetron to waveguide adapter before, following GBPR guidelines

http://67.225.133.110/~gbpprorg/mil/emp3/index.html


Other then crappy materials use, is that the right way to do it? Can anything but conductivity be improved some how? I am still learning how to use HFSS.

I did not test mine yet because I wanted to make a separate HV/Heater supply so I can test it at low power levels, and I did not make a dummy load yet or test it for leaks etc. I only made the physical adapter up to a N connector, I don't care for the whole spark gap radar thing he builds.

I thought maybe rather then some sheet metal shit, it might be possible to couple a magnetron into a commercial waveguide (WR430) segment with a proper end launcher on it?

I'm kinda looking at what I built and I'm thinkin I should not turn this on.

[tkamiya]

Does it look like this?

http://typnet.net/Articles/WeedKiller.pdf

[coppercone2]

kinda, but I found you can buy proper ones: just search WR430 magnetron on google and you can buy welded ones from alibaba.

https://xhwb.en.alibaba.com/product/60390304891-802057244/manufacturers_of_rectangular_waveguide_for_1000w_1500w_microwave_magnetron_WR_340.html

I am guessing its fairly proper but uses poor materials. You can probably replicate it with copper plate and silver braze.

[floobydust]

I'm seeing the same standard coupler design and dimensions whether microwave oven or 3kW industrial.
Toshiba industrial magnetron for the 3kW part "Coupling without the standard output coupler can be checked using E3328 impedance probe VM-06700." But I can find nothing on the probe. Could you not undervolt the tube to make measurements?

It looks like people don't want to reinvent the wheel. Are you using HFSS to design one from scratch?

https://www.alibaba.com/product-detail/microwave-oven-parts-for-waveguide-for_60407699009.html

[coppercone2]

I am finding HFSS very difficult to use. I did not have time to sit down with it yet, maybe more in the colder months because its going to be difficult to do anything pleasant outdoors soon. I don't want to waste the good weather or peoples good warm weather moods behind a simulator at this point in time.

And yes, if I were to actually use one of these magnetrons I would use a regulated supply and regulated heater coil, I want a electrical tool not a food or lumber heater. I plan on under rating it anyway.

[floobydust]

Thanks, now I can't stop staring at the webpage bottom .gif
Micro Denshi Co. Ltd.  Data analysis of electric field distribution of microwave heating device analyzed by electromagnetic simulator
They have a neat 360 LED board to visualize the oven field, I wonder how it does not get nuked.

[coppercone2]

I have seen some Ukranian on youtube build a 2d neon tube grid for that purpose.

yea that GIF makes me happy.



I wonder if you can round off that injector or something to make the fields near the top decay quicker or spread out more, the corners look like they can get hot.

[chris_leyson]

Found this paper http://www.itim-cj.ro/~vasile/Microwave%20Generator.pdf Anode to back wall distance 22mm seems about right. If you want variable output power then YJ1530SP might be the one to go for and you might be able to get the drawing from National for the coax coupler. https://www.relltubes.com/filebase/en/src/Datasheets/yj1530sp.pdf

[tkamiya]

I wonder if employees at Micro-denshi get to use their products for heating up lunch? 

[Nitrous]

I realize this is a narco thread, but the links are dead.

[coppercone2]

I never did anything with this, but you might be interested to try to find my post about microwave plasma arc welding, which is a super interesting application of this.

I believe its the most "oxy acetylene torch" like electric arc that can be made, but the hand piece leaves something to be desired (machine use only, limits the interest), grounding the work piece has less of a effect when plasma is made this way.

It seemed a bit crazy but when you see that hand held laser laser welders took off, this one looks benign in comparison 

the application is sheet metal, and unlike laser welders, it looks like you might be able to have really shitty parts fit up (aka its practical) without laser cut CMM measured parts, so it can realistically be used to repair your typically deformed and warped sheet metal stuff. I kinda imagined with the laser welders taking over, its going to be like "we can do the weld in 10 seconds!" but they will forget to mention 4 hours of fitting work one to set the weld, along with and $25k of fixtures, formers, etc to setup a repair on a cosmetic skin part


but, as far as dead research, microwave plasma arc welding is... mad dead