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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
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 2 years 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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jmorris
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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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jmorris

James Morris

Reply to @l0kod@mastodon.social
@l0kod is there a link to the LVBS talk on the HEKI page?
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jmorris
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l0kod@mastodon.social

Mickaël Salaün

We gave two talks about Hypervisor Enforced Kernel Integrity and Linux Virtualization Based Security at - Leveraging KVM or Hyper-V to harden a VM:
- global project overview: https://lpc.events/event/17/contributions/1515/
- KVM implementation: https://lpc.events/event/17/contributions/1486/
- code: https://github.com/heki-linux

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jmorris
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polpo@bitbang.social

Ian Scott apple_inc 🐙

2.0 is officially released! It's an ISA card that can emulate Gravis Ultrasound, Adlib, CMS, Tandy 3-voice, MPU-401 w/ Intelligent Mode, and gameport joysticks!
This new version is 100% factory assembled and ready to just plug and play.
And it's open hardware: all design files are available under CERN OHL v2 Permissive license, so if you want to make (or improve) your own you can!
Available at my Tindie Store: https://www.tindie.com/products/polpo/picogus-sound-card-emulator-for-isa-retro-pcs/

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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

Reply to @g4dbn@mastodon.radio
@g4dbn @azonenberg those dishes should be well-sized for for > 100 GHz, especially with good surface RMS and feed accuracy. btw, something that would be broadly useful are matching plates for common Ku band satcom feed horns with a circular waveguide connection, to wr75 or wr90.
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jmorris

James Morris

Reply to @g4dbn@mastodon.radio
@g4dbn @azonenberg the possibilities…! I’m interested to know if you will be able to do very small runs of custom uwave & mmWave plumbing for amateur use.
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jmorris

James Morris

Reply to @securepaul@fosstodon.org
@securepaul you can run for this
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jmorris
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bluca@fosstodon.org

bluca

ICYMI: we've recently done some work on the documentation rendered on freedesktop.org, and now all manpages have a drop-down menu to select the release version to visualize. Also individual options are now tagged with the version they were first introduced in. These improvements should hopefully help readers with understanding what options are available in what version.

Example: https://www.freedesktop.org/software/systemd/man/255/systemd.exec.html

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