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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/
☠️ https://www.facebook.com/w7txt


Imagine being a billionaire and not living in a house like this.
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Really “enjoyed” hand soldering this VSSOP device with 0.5mm pitch. Time to get a hot plate reflow setup.
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Should I install this software?
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Very excited to have a paper published in DUBUS. I’ve been reading this journal for about a decade and never imagined when I started that I’d be published there. The journal is also translated into German (or English) by the editors, as it’s a dual language publication.

#hamradio #amateurradio #microwave
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Edited 2 months ago
“Don’t ask me how I did it I just did it it was hard”. J/K, I will document this properly soon and it’s much simpler and than it looks.
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It feels like cheating to use these pre-cut wire links for soldering (vs. push-in breadboard), but I’m over making these by hand. #amateurradio #hamradio #electronics
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Prototyping a monitor circuit for GaN RF power amplifier devices. This is indicating drain current and heat sink temperature, and can be expanded to other measurements as needed. What started as a ‘simple’ project became an entire side quest. This uses an Arduino Pro Mini, an INA169 current sensor, and a thermistor. Could be done more simply with a PIC but this is what I had. The cheap OLED display self destructed not long after this photo, as I fed it 12v instead of Vcc.
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Got slightly distracted in midjourney.

This is Seattle, Cascadia in 3357, on the 1000th anniversary of The Fault.

Idaho's Mount Mersini-Houghton is in the background. Also notable is the newly refurbished Space Needle Memorial.
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Found an exit.
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two days later…
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More progress on the 30W 10GHz amplifier. Almost ready to test.
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Mystery object challenge: what is this and in how many ways can it hurt you?
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Seen @ work
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Finally learning to mill, in a work makerspace. This is a game changer for all kinds of projects. My first task is smoothing out a copper heat spreader, which was extruded and less than ideal for heat transfer.
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Finally bought what seems to be the bible on #radioastronomy - Kraus. I have several other books which seem to defer to Kraus on some of the “basics”. Good to have all of the essential information in one place. Seems this book is only currently available as ring bound or a cheap paperback. One specific goal I have here for 2024 is to properly understand wave polarisation & Stokes parameters.
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Edited 5 months ago
Finished making a thing. This is a power supply for the 30W 10 GHz amplifier I’m working on. It should also be able to power the transverter, IF radio, & relays. I’m resisting the temptation to add an MCU and display. For now.

(Note: the 50 Hz label should say 60 Hz)

#hamradio #electronics #amateurradio #microwave #qro #sspa
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Close up of the thermistor, which is a tiny bead in the middle of the photo.
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Ok, I think I understand this a little more now. The horizontal bar in the waveguide is a thermal mass, which heats up in the presence of RF. The detector thermistor is attached to it (too small to see here), and it will closely follow the temperature of the bar. A bias current runs through the thermistor, and also the isolated compensation thermistor. The comp thermistor has its own thermal mass, which is the gold plated square, and a couple of rectangular blocks, which I assume were selected and pasted in by hand during construction, and this can be finely adjusted via the screw. Not sure exactly where the compensation thermistor is yet, and the circuit diagram shows a capacitor here somewhere. Could be both are in the white block, which looks like a modern SMD cap.
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