Justin K5EM

@[email protected]
258 Followers
266 Following
221 Posts

Tech, ham radio, hacking, weather. I enjoy experimenting with SDR, designing and testing antennas, contesting (usually with the team at KZ1W), SOTA/POTA, and satcom. Professionally I'm a hardware/FW/SW engineer and have spent most of my career in the drone industry. I enjoy making maps, both with drones and otherwise, with a focus on multispectral data collection and analysis.

Created http://satmatch.com to help satellite rovers better plan operations.

DXPedition @T88WA

He/him

BlueSky@k5em.bsky.social
Github@poynting
Show threadJustin K5EMFeb 20
@IU1KGS state QSO party season is starting soon as well. Also a good opportunity to pick up new states and counties.
Justin K5EMNov 28
tomiantNov 27

Prof. Nick Zentner (Geology) at Washington State showing an accurate representation of the ice age floods that shaped a lot of the canyons we see today in NA

https://piefed.social/c/interestingasfuck/p/1516797/prof-nick-zentner-geology-at-washington-state-showing-an-accurate-representation-of-the

Prof. Nick Zentner (Geology) at Washington State showing an accurate representation of the ice age floods that shaped a lot of the canyons we see today in NA

Prof. Nick Zentner (Geology) at Washington State showing an accurate representation of the ice age floods that shaped a lot of the canyons we see t…

Justin K5EMJul 29, 2025
John TJul 29, 2025

I could use some #retrocomputing help!

I recently acquired a (homebuilt) device from a friend, and as a labor of love, I'm trying to restore it for him.

It has a single broken key (contacts are broken), which I don't see any good way to fix without replacement.

Anyone have any idea what this keyboard is?

Boosts are appreciated!

EDIT: I'm quite sure the prosigns (CH, CT, KN, AR etc) are label modifications. Also, the device origin is Australia or Canada.

Justin K5EMJul 8, 2025
maketveeJul 8, 2025
I made an LED hat by weaving LED pebble strings with poly rattan. Pure braiding, no glue involved. 475 LEDs in total, controlled by a @wizard Pixelblaze. More pictures 👇🧵
Show threadJustin K5EMJun 24, 2025
@ftg @mxshift @dysfun agree. There's the original Alford loop patent, but it doesn't really reflect what seems to be going on here, even though the D&M is called a modified Alford loop. https://patents.google.com/patent/US2283897A/
US2283897A - Antenna system - Google Patents

Show threadJustin K5EMJun 24, 2025
@ftg @mxshift @dysfun that is what the schematic seems to say, but I'm actually not completely sure now, after a lot more research. Everyone regurgitates the same schematic image, but the best image I've found of it is this one from https://carleton.scholaris.ca/bitstreams/52972888-15b0-48e4-a962-c3af09b38cc2/download
Show threadJustin K5EMJun 24, 2025
@ftg @mxshift @dysfun https://sites.calian.com/app/uploads/sites/8/2023/11/Tallysman-Intergeo-2020.pdf
Justin K5EMJun 16, 2025
Erik BosmanJun 16, 2025

I modded an IKEA OBEGRÄNSAD lamp with my LED driver & custom firmware. It now displays 16bit grayscales @ 120 FPS.

https://github.com/brainsmoke/esp32leddriver/tree/master/firmware/stm32/obegraensad

Show threadJustin K5EMJun 7, 2025
@ExplodingLemur @m1geo if you order a replacement, any chance you can order a spare and let me buy it off you? I've been trying to purchase for a while but never got a response. Happy to send you a paid label.
Show threadJustin K5EMJun 7, 2025
@ExplodingLemur @m1geo if you order a replacement, any chance you can order a spare and let me buy it off you? I've been trying to purchase for a while but never got a response. Happy to send you a paid label or just buy you a ☕.