Hacker News: thatcherc

Passive Bistatic RADAR using the NISAR satellite signal

thatcherc — Mon, 30 Mar 2026 18:35:46 +0000

Article URL: https://github.com/jmfriedt/NISAR_pbr

Comments URL: https://news.ycombinator.com/item?id=47577989

Points: 5

# Comments: 0

New comment by thatcherc in "New 'negative light' technology hides data transfers in plain sight"

thatcherc — Fri, 13 Mar 2026 20:49:36 +0000

Link to the paper: https://www.nature.com/articles/s41377-025-02119-y

From the abstract:

> Here, we demonstrate a covert communications method in which photon emission is rapidly electrically modulated both above and below the level of a passive blackbody at the emitter temperature. The time-averaged emission can be designed to be identical to the thermal background, realizing communications with zero optical signature for detectors with bandwidth lower than the modulation frequency

It sounds like maybe they're modulating the emissivity of a diode up and down so that over time, its IR spectrum looks like black body radiation. Only someone looking at the intensity of the thermal radiation coming from the diode at really fast timescales (kilohertz or megahertz) would notice that there was a signal being transmitted.

New comment by thatcherc in "Show HN: DD Photos – open-source photo album site generator (Go and SvelteKit)"

thatcherc — Tue, 10 Mar 2026 14:22:19 +0000

This looks great! I've been using ThumbsUp[1] for a similar purpose (creating a gallery of photos I can push S3), but adding album and photo captions required some un-ergonomical tricks. I'll try this out!

[1] - https://github.com/thumbsup/thumbsup

New comment by thatcherc in "Ask HN: Share your personal website"

thatcherc — Thu, 15 Jan 2026 01:32:59 +0000

https://jthatch.com/ !

New comment by thatcherc in "More atmospheric rivers coming for flooded Washington and the West Coast"

thatcherc — Wed, 17 Dec 2025 02:31:25 +0000

You might have been thinking of https://earth.nullschool.net/

New comment by thatcherc in "The terminal of the future"

thatcherc — Tue, 11 Nov 2025 22:21:35 +0000

I appreciated the Pluto.jl mention! Going from Pluto notebooks that understand data flow to Jupyter notebooks where you have to tell the computer which order to run the cells in is always baffling to me. Why doesn't Jupyter know the run order and dependencies already? The way Pluto handles dependencies between code cells is really just so nice.

New comment by thatcherc in "Beginner Guide to VPS Hetzner and Coolify"

thatcherc — Sun, 05 Oct 2025 11:21:12 +0000

Kinda weird - Coolify doesn't come up except in the first and last paragraphs. Seems like the page is incomplete or just mis-titled.

Engineered plants with doubled carbon uptake and more seeds and lipids

thatcherc — Tue, 16 Sep 2025 10:22:36 +0000

Article URL: https://phys.org/news/2025-09-scientists-carbon-uptake-ability-seeds.html

Comments URL: https://news.ycombinator.com/item?id=45260363

Points: 3

# Comments: 0

New comment by thatcherc in "NASA's Guardian Tsunami Detection Tech Catches Wave in Real Time"

thatcherc — Mon, 15 Sep 2025 11:07:26 +0000

Yup, slight mix-up. Gravity waves are waves in the ocean and atmosphere (or other fluid bodies) where Earth's gravity is the restoring forces that causes wave propagation. Gravitational waves are the waves in spacetime caused by powerful astronomical events like black hole mergers.

New comment by thatcherc in "OpenIPC: Open IP Camera Firmware"

thatcherc — Mon, 04 Aug 2025 16:27:52 +0000

Cool! It looks like the Wansview Q5 has a similar SoC/camera/wireless setup as the Wansview W7, which as an installer guide on the Thingino wiki [1]. I wonder if that same installation process (but with the q5 firmware) would work. For $16 I'm inclined to try it out.

[1] - https://github.com/wltechblog/thingino-installers/tree/main/...

New comment by thatcherc in "Low cost mmWave 60GHz radar sensor for advanced sensing"

thatcherc — Fri, 01 Aug 2025 01:08:46 +0000

Thanks! The author's blog is a great find as well - https://www.dm5tt.de/

New comment by thatcherc in "Low cost mmWave 60GHz radar sensor for advanced sensing"

thatcherc — Mon, 28 Jul 2025 18:03:51 +0000

> The analog ones are easy to play with. You just need a DAC to drive their VCO and then can sample the I/Q pins with an ADC

Do you have any reference or notes on how to access the IQ pins on one of these devices (ideally one of the FMCW ones)? I've been wanting to play around with one of these 24 GHz or 60 GHz units for coherent radar but it seems like most of the boards only report on distances over serial links. If there's an easy way to tap into the analog IF signal after down conversion I'd love to see how to do that!

New comment by thatcherc in "Locally hosting an internet-connected server"

thatcherc — Wed, 18 Jun 2025 11:28:54 +0000

Cool! Do you like that approach? I've thought about setting up that exact thing but I wasn't sure how well it would work in practice. Are there any pitfalls you ran into early on? I might give it a shot after your "very easy to set up and operate" review!

New comment by thatcherc in "Devstral"

thatcherc — Wed, 21 May 2025 18:35:00 +0000

I would recommend just trying it out! (as long as you have the disk space for a few models). llama.cpp[0] is pretty easy to download and build and has good support for M-series Macbook Airs. I usually just use LMStudio[1] though - it's got a nice and easy-to-use interface that looks like the ChatGPT or Claude webpage, and you can search for and download models from within the program. LMStudio would be the easiest way to get started and probably all you need. I use it a lot on my M2 Macbook Air and it's really handy.

[0] - https://github.com/ggml-org/llama.cpp

[1] - https://lmstudio.ai/

New comment by thatcherc in "The chroot Technique – a Swiss army multitool for Linux systems"

thatcherc — Wed, 09 Apr 2025 18:34:21 +0000

> you can even chroot into foreign CPU architectures, which is a handy thing to have when you mount your phone's eMMC

This sounds very interesting! What's the scenario where you'd do this? Would you be, for example, emulating an ARM processor with qemu on an x86 computer and chrooting into Android on an eMMC?

New comment by thatcherc in "NASA Successfully Acquires GPS Signals on Moon"

thatcherc — Wed, 05 Mar 2025 13:09:20 +0000

A challenge there is that there are very few stable lunar orbits! High orbits are perturbed by Earth's gravity (3-body problem) and low lunar orbits are perturbed by the lumpy distribution of mass in the Moon's interior [0]. Lunar GNSS satellites with a little bit of onboard propulsion could probably correct for some of these perturbations but once they ran out of fuel they would have a limited orbital lifetime.

[0] - https://en.wikipedia.org/wiki/Lunar_orbit#Perturbation_effec...

New Data Reveal Climate Change-Driven Insurance Crisis Is Spreading

thatcherc — Fri, 03 Jan 2025 20:21:08 +0000

Article URL: https://www.budget.senate.gov/chairman/newsroom/press/new-data-reveal-climate-change-driven-insurance-crisis-is-spreading

Comments URL: https://news.ycombinator.com/item?id=42589112

Points: 12

# Comments: 1

New comment by thatcherc in "Just want simple TLS for your .internal network?"

thatcherc — Tue, 22 Oct 2024 18:16:29 +0000

This sounds like something I'd want to do! Is the idea that you'd have a public domain name like "internal.thatcherc.com" resolve to an internal IP address like 10.0.10.5? I've wondered about setting this up for some local services I have but I wasn't sure if it was a commonly-done thing.

New comment by thatcherc in "Show HN: Automated smooth Nth order derivatives of noisy data"

thatcherc — Thu, 17 Oct 2024 13:35:26 +0000

Yup, my data is nicely gridded so I can use the convolution approach pretty easily. Agreed though - missing data at the edges or in the interior is annoying. For a while I was thinking I should recompute the SG coefficients every time I hit a missing data point so that they just "jump over" the missing values, giving me a derivative at the missing point based on the values that come before and after it, but for now I'm just throwing away any convolutions that hit a missing value.

New comment by thatcherc in "Show HN: Automated smooth Nth order derivatives of noisy data"

thatcherc — Wed, 16 Oct 2024 23:03:09 +0000

I actually have one for this! Last week I had something really specific - a GeoTIFF image where each pixel represents the speed in "x" direction of the ice sheet surface in Antarctica and I wanted to get the derivative of that velocity field so I could look at the strain rate of the ice.

A common way to do that is to use a Savitzky-Golay filter [0], which does a similar thing - it can smooth out data and also provide smooth derivatives of the input data. It looks like this post's technique can also do that, so maybe it'd be useful for my ice strain-rate field project.

[0] - https://en.wikipedia.org/wiki/Savitzky%E2%80%93Golay_filter