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Linux Kernel security developer, working for Microsoft. Also W7TXT. Views are my own.
Topics: #Linux #kernel #security, #amateurradio, #RF, #hamradio, #electronics, #science, #radioastronomy, #physics, #space, #arduino.

📡 https://w7txt.net/
🐧 https://blog.namei.org/
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jmorris

James Morris

Performed some more mm-wave testing at the PNW Microwave build day, looking at the output of the 40-50 GHz quadrupler. Thanks to W7GLF for bringing in his spectrum analyzer & external mixer. Results forthcoming.


#amateurradio #hamradio #microwave #mmwave #electronics
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jmorris

James Morris

Testing a Ka band LNB, specified for 20.2-21.2 GHz. I could not see any signals beyond 22.8 GHz (well short of the 24 GHz amateur band), but that could be due to issues at the IF level. Worth investigating further. I was able to see a good signals at 22.2, an important radio astronomy frequency. #amateurradio #microwave #radioastronomy
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jmorris

James Morris

Edited 1 year ago
Just received this in gmail. Seems like my ad blocker and/or ublock origin is working well here to stop them tracking my behavior. I have in fact been opening their emails. UbO for the email shows dozens of blocked requests to play.google.com and other related sites.
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jmorris

James Morris

Current non-fiction reading pile.
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jmorris

James Morris

It’s not everyday you get to touch an SR-71. It didn’t quite feel like metal, the paint seems to dampen it?
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jmorris

James Morris

Edited 1 year ago
Got distracted working on slides, used the AI in powerpoint to make some alien cities. Here's one on an accretion-disk world. The "water" is not for swimming.
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jmorris

James Morris

At Linux Plumbers, toolchain track. @linuxplumbersconf
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jmorris

James Morris

Reply to @jmorris
I now have a LOVELY combination of C and C++ to clean up one day.
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jmorris

James Morris

Working on some long-needed updates to my 1.2m dish setup. Mounting an azimuth sensor (ETS25 absolute encoder) directly under the Az slew drive. A previous belt-driven version was too complicated. This is all upside down, btw. #amateurradio #hamradio #radioastronomy #electronics #microwave
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jmorris

James Morris

Made some millimeter waves today, presumably at 47.088 GHz. Using a Kuhne synth at 11.772 GHz into a WA1MBA quadrupler. I’m able to detect power in this band (6mm), but not frequency (yet). #microwave #mmwave #hamradio #amateurradio.
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jmorris

James Morris

Reply to @selzero@syzito.xyz
@selzero
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jmorris

James Morris

Reply to @mcdanlj@social.makerforums.info
@mcdanlj I’ve tried a YG-1 spiral flute tap here now and it is working well. It seems to need much lower torque than regular or form taps. I think the form tap is more precise and will provide more strength, but this is not critical in my application.
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jmorris

James Morris

Pro tip ?
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jmorris

James Morris

Saw a lot of Aurora flying over Greenland on the way to Linux Security Summit EU. This is the best I could do with an older iPhone #linux #linuxsecuritysummit #space #spaceweather #hamradio #amateurradio
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jmorris

James Morris

Reply to @mcdanlj@social.makerforums.info
@mcdanlj a mill would be great but I currently have no room for one. Btw, I ended up brute force drilling the broken taps out with a solid tungsten carbide bit (which broke twice), then I was able to drill & tap for 6-32. There was enough slack in the copper spreader to handle some misalignment. The rest of the 4-40 were done very carefully with a form tap and tap magic. I’ll try the spiral flute next.
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jmorris

James Morris

The “2nd level of hell” starter kit for metalworking.
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jmorris

James Morris

After many hours, including re-capping the power supply (no dice, but worthwhile in any case), and tracing through most of the upper section, I finally found the issue with this Tektronix spectrum analyzer. A tantalum cap on the horizontal storage board failed and shorted the +15v bus. Replaced it and the SA seems to be working ok so far. #hamradio #amateurradio #electronics
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jmorris

James Morris

Metalwork for the linear amp is going GREAT. First I drilled the wrong hole sizes for the heat sink, then broke two 4-40 taps. Will figure out how to extract these then try a thread forming tap instead of a cutting tap.

#hamradio #amateuradio #electronics
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jmorris

James Morris

Weekend goal: get the metalworking started for the HF/6M amplifier project. kW+ RF deck by W6PQL. #amateurradio #hamradio #electronics #radio #meteorscatter
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jmorris

James Morris

Edited 2 years ago
Anyway, something good -- found a building full of electronics stores in Singapore a couple of weeks ago. So much stuff you don't see on shelves in the US or Australia now, all kinds of niches.

Location is Sim Lim Tower.

#electronics #singapore #hamradio #amateurradio #maker
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