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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

Troubleshooting a Tek spectrum analyzer PSU. Gonna need a bigger boat. I mean, an ESR meter.
Any recommendations on a budget ESR meter? 🤔
#electronics #hamradio #amateurradio
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jmorris

James Morris

Edited 2 years ago
Best meteor scatter rx so far: 1127 km. With just a dipole & preamp on 6m.

#hamradio #amateurradio #msk144 #meteorscatter #meteors #meteor #space #physics #rf #radio
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jmorris

James Morris

The local electronics store (Vetco) is an Aladdin's cave of test equipment at the moment.
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jmorris

James Morris

Edited 2 years ago
Overnight meteor scatter rx haul on 6m, longest distance so far.

#hamradio #vhf #msk144 #6m #meteorscatter #perseid #meteors #space #amateurradio #wsjt-x
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jmorris

James Morris

Reply to
@va3db @zazzoo setting this up is easy if you can do FT8 or WSPR already, and have something as simple as a dipole for 6m. Run wsjt-x in msk144 mode overnight during this weekend and see if you catch anything. I just set this up last night and it worked. Note that signals closer than 500km are probably not MS.
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jmorris

James Morris

Finally completed the initial version of 'fp_util', which allows you to control & monitor an Eltek Flatpack2 power supply, using an Arduino with a CAN bus shield.

https://github.com/xjamesmorris/fp_util

These PSUs are intended for telecoms racks, as chargers for 48v batteries, and supply 2kW or 3kW. Surplus units are useful for LDMOS RF amplifiers, and EV / e-bike etc. battery charging.
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jmorris

James Morris

Load testing my 50v power supply project, using a cheap hot water heater element in water (briefly, < 1 min). Dissipates about 350W. I’m thinking about mounting it into an empty paint can which can hold several gallons. Anyone know if mineral oil would be better than water for this?
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jmorris

James Morris

Sol, bruh.

#hamradio #amateurradio #space #spaceweather #solar #ionosphere #hf #rf
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jmorris

James Morris

Catching up on the recent SSITC security conf in France -- some is in English.

https://www.sstic.org/2023/programme/

#infosec #security #linux #opensource
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jmorris

James Morris

Excited to get this (~3rd in reading queue). Mersini-Houghton’s multiverse theory is the only one which has been tested, AFAIK.
I find it difficult to understand (e.g pre-Universe “energy landscape”) so I’m hoping the book will help.
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jmorris

James Morris

Reply to @jmorris
What is stopping you from coding like this?
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jmorris

James Morris

Reply to @jmorris
Also...
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jmorris

James Morris

Trying out the AI image generation in Powerpoint.
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jmorris

James Morris

Reply to @jmorris
@Haijo7
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jmorris

James Morris

My ideal house. #goals #hamradio #amateurradio #microwave
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jmorris

James Morris

Just looking at some code of mine from 1994, for satellite tracking, and found this optimistic gem.
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jmorris

James Morris

This is really something. #antipattern
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jmorris

James Morris

Slow but sure progress on my 1kW HF/VHF amplifier power supply. Bought a PCB for the Eltek module and decided to solder the output wires (10 AWG THHN) rather than use the more common XT-60 connectors. After some research, I found out that XT-60s, commonly used for drones & RC batteries, are only rated at 30A continuous. The 60A figure is for peak current, and the available specs are very light on details generally. This PSU is being built for 40A continuous (at 50v), so the XT-60 is not sufficient. Next up will be to connect this Sparkfun CAN shield to configure & monitor the Eltek.
#hamradio #amateurradio #electronics
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jmorris

James Morris

Reply to @jmorris
And here is the power supply. 50 VDC @ 40A max. I’m using a surplus Flatpack2 server PSU, with space for a 2nd to run in parallel or backup. Also room for 28V (for relays) & 13.8V modules.
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jmorris

James Morris

Next project: assemble these components from W6PQL into an MF/HF/6m amplifier. It’s specified for 1kW but I suspect it can do more. #amateurradio #hamradio
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