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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
jmorris

James Morris

Reply to @jmorris
Amazingly, you can some online courses in math from top tier universities, for free: https://www.edx.org/search?q=linear+algebra&tab=course
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jmorris
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LinuxSecSummit

Linux Security Summit 🐧

📢 The CfP for the 2024 Linux Security Summit North America is open!

https://events.linuxfoundation.org/linux-security-summit-north-america/program/cfp/

Location: Seattle, USA

Dates:
- CfP close: January 21, 2024
- Speaker notifications: February 06, 2024
- Event: April 18-19 2024
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jmorris

James Morris

Reply to @Gina@fosstodon.org
@Gina yes, you will get burned in 10-15 mins even through car windows.
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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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LinuxSecSummit

Linux Security Summit 🐧

Edited 1 year ago

Videos and slides from the 2023 Linux Security summits may be found here:

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jmorris
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pid_eins@mastodon.social

Lennart Poettering

This is the good stuff:

→ https://fedoramagazine.org/create-images-directly-from-rhel-and-rhel-ubi-package-using-mkosi/

written by @zbyszek

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jmorris
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azonenberg@ioc.exchange

Andrew Zonenberg

Getting ready to do a test run of my probing class for my first in person beta audience.

This will be my second test run of the lecture (first was a YT livestream a year or so ago) and the first time doing the labs.

There's still more meat I want to add especially towards the end of the class (e.g. the section on current probing is just a handful of slides, and there's no lab for it yet as i don't have any current probes here) but it'll be good to get feedback from a test audience on pacing and content.

Probably going to do at least one more test round early next year before I start doing it officially. Looking into getting registered with IEEE to provide approved continuing education / professional development hours as well.

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jmorris

James Morris

Reply to @penguin42@mastodon.org.uk
@penguin42 also, power factor.
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jmorris

James Morris

Reply to @jmorris
There's internal filtering in the LNB, both at the RF and IF levels, which will be limiting factors in how out of spec this can be operated at. It may be possible to adjust the internal LO upwards, and some of the filtering, but likely at some performance cost.
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jmorris

James Morris

Reply to @jmorris
Test setup: 11.1 GHz output from a Kuhne freq synthesizer, into a small Log Periodic Dipole Array antenna. This signal will include a small amount of harmonics, and in this case, I'm utilizing the 22.2 GHz first harmonic (which I independently verified with the spectrum analyzer), which mixes with the LNB internal LO of 19.2 GHz, to produce a 3 GHz IF (22.2 - 19.2), which is displayed on the spectrum analyzer. I also verified operation by putting my finger over the waveguide input. This a pretty weak signal, given the additional losses from the PCB antenna, and all of the circuitry in the LNB and the Bias-T, which are out of range. It's working but at what cost?
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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

Reply to @gigabecquerel@chaos.social
@gigabecquerel @stdlogicvector until seeing this, I'd assumed that going below 4K was infeasible for a hobbyist (assuming you can even get LHe now). Any idea if these turn up as 'for repair / parts' on the surplus market?

ETA: or does it need He3 ?
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jmorris

James Morris

@jcutting this is the content I signed up for

RE: https://social.vivaldi.net/users/jcutting/statuses/111446741178195059
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jmorris

James Morris

Reply to @Chigaze@mstdn.ca
@Chigaze definitely feel that way with awk.
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jmorris

James Morris

Reply to @g4dbn@mastodon.radio
@g4dbn @azonenberg cool, I'm planning to attend and also have at least one paper.
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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

Reply to @azonenberg@ioc.exchange
@azonenberg @g4dbn btw, there is a microwave group in the Seattle area: https://pnw-microwave.com/
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jmorris

James Morris

Reply to @jmorris
I know some, but not enough linear algebra for the cat book. There are good online courses, thankfully. It may take a while.
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jmorris

James Morris

Current non-fiction reading pile.
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bluca@fosstodon.org

bluca

v255-rc2 is out, go test it or else we'll deprecate your favorite feature https://github.com/systemd/systemd/releases/tag/v255-rc2

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