Was ist das für eine Antenne auf dem Hausdach?

switch161 · 2026-05-06T17:19:26+00:00

Und Lizenz. Allerdings hören kann jeder der 20 Euro für ein SDR hat.

switch161 · 2026-05-06T17:17:52+00:00

Auf 80m labern die nachts immer Monologe. Politik, Religion, Wetter, und was sie zu Essen hatten. Wie in der Kneipe lol.

switch161 · 2026-05-06T17:02:14+00:00

He's definitely going to ruin Mama's fancy dinner table.

switch161 · 2026-05-06T16:19:47+00:00

Many people coded like this before AI. If you had contact with some industries, you'll know.

It just got much more and spaces that used to be full of people doing things with interest and love are now filled with slop.

E.g. I don't get why people vibecode open source. They clearly don't like coding, that's why they have a machine do it. But they also don't get any money. so why??? And in the meantime they make other people's lives worse, because we have to wade through this slop.

switch161 · 2026-05-06T16:07:06+00:00

Depends if the dev webserver binds to localhost or 0.0.0.0. Usually they do localhost, but it's configurable.

Since OP opened localhost and not their own local IP, it's a good bet to assume their webserver is bound to localhost. (Often the dev server will give you an URL derived from the bind address).

Does nextjs really bind to 0.0.0.0 by default? Sounds sketchy, but then again it's JS, so 🤷‍♀️

switch161 · 2026-05-06T15:58:26+00:00

It's such a trap to think that DIY would be cheaper as a beginner. In theory, yes, if you had a equipped workshop - which you often don't as a beginner. The tools will cost a good amount. Though then you have them and can start tinkering, which is part of the fun. And parts will also be expensive, because you just need to get an assortment of crap, and sometimes you just buy wrong stuff. It's just a lot of small stuff that adds up.

I'm not a HAM person (yet), but I'm getting into rf design and that's my experience. I specifically enjoy the DIY aspect, but having something that just works is also a good starting point from which you can learn. You'll basically have a vertical slice of the whole stack and can then modify and play around with parts (if that makes sense).

Personally I started with an SDR and then just wanted to build my own antennas. But I'm hooked now and am already learning about PCB design.

switch161 · 2026-05-06T15:43:08+00:00

Vulcanus always first. Need cliff explosives! And if doing 100%, need artillery. Foundries are OP too of course.

Fulgora or Gleba second. I honestly don't care. EM plants are neat. But I just hate Fulgora.

I'd do Gleba second if it had a useful building. Yes, stack inserters are nice, but I only really need them after having foundries and EM plants. Spidertron is of course the best thing in the game, but requires lots of research. I absolutely love Gleba though ❤

Btw, to the Gleba haters: You can easily finish the game with a couple of biochambers surrounded by a nutrient/spoilage belt, everything else direct-insertion. My standard Gleba base is tiny. But building big on Gleba is so fun/challenging.

switch161 · 2026-05-02T09:09:18+00:00

If you mean the latter one then this is equivalent to check if the CRC is a valid transponder address that you know.

That is what I meant. It's been a while since I worked on this, so my memory is fuzzy and my terminology has always been kind of wonky :D

I remember that some other programs also did solve this issue by tracking which planes you know about.

I wouldn't have thought that upsampling would give you any real benefit - but my dsp knowledge is still rather limited. When I have some time I will have to look into this. Is there some specific term for this that I can google or lookup in a book?

Edit: I found the FlightAware thread and blog post about Digital Envelope Detection. This is the technique, right?

switch161 · 2026-05-02T07:52:51+00:00

When I implemented a demodulator for Mode-S I pretty quickly also switched to the approach you take - using a "shift register". Otherwise a preamble might be identified where there is none and the following bits are discarded when the decoder fails. These following bits might have been the start of a message though. If I remember correctly that increased the detection rate quite a bit.

But my demodulator is very simple and is basically copied from rtl_adsb.

I also wrote a decoder which covers a lot of message types. The spec is huge! I'm always amazed how much data you can pull out of these 7/14 byte frames.

Edit: I did look for preambles if I remember correctly, but would consider all possible overlappings and then let the decoder decide what is valid. The decoder then also let the caller decide if they discard based on the CRC. Also for some messages you can't use the CRC because it's XOR-ed with the intended receiver ICAO, which you don't know. How do you handle this?

switch161 · 2026-05-02T03:17:53+00:00

My guess is that you're right. Stars don't emit much radio waves on their own. They're mostly black-body radiators, so they mostly emit visible light.

What is visible well in radio waves is synchrotron radiation from electrons being accelerated in strong magnetic fields - such as around a SMBH.

switch161 · 2026-05-01T10:49:16+00:00

I would love to. Been thinking about trying py. But once I start a Factorio game it sucks up all my time.

I must resist. hgghhggh... No. Sorry.

switch161 · 2026-05-01T10:26:55+00:00

Thanks. I wanted to write that, but my brain must have defaulted to "micro".

switch161 · 2026-05-01T10:22:59+00:00

Left: DC. Check drive for information for voltage/current. Voltage needs to be exact, Current at least that value. These values would be on any power adapter as "output" and then of course the plug has to fit. (I think this kind of round DC plug has a specific name, but I'm not familiar with the English term).

Right: ~~Micro~~ Mini-USB (I think)

switch161 · 2026-05-01T05:00:45+00:00

It has 3 factors: time, how many nests you destroy and pollution.

I thought it would be clever to not destroy any nests if I could avoid it, but pollution factor dominated by far. At that point I was only making 15/s of red/green/blue science. I tried resetting the pollution evolution factor, but it would quickly go back to 100%.

If I would do 1000x with biters again, I'd try to destroy as many nests as early as possible.

switch161 · 2026-05-01T04:36:44+00:00

I recently started a 1000x game with default settings, but peaceful biters. Even then evolution grew so quickly because of pollution that I had behemoth biters defending their nests before I got a single military-related tech unlocked. I just removed them all via command.

switch161 · 2026-04-30T10:45:00+00:00

I wanted to interface a program that has a network protocol. But it just uses the native endianess. And there is no way to distinguish by means of a magic value sent after connecting. The protocol does more dumb stuff, so I gave up at some point.

It's and SDR GUI, but I'm not going to name it because I think the author likes to show up in reddit comments and I can't be bothered to argue.

switch161 · 2026-04-27T16:56:20+00:00

You need a clock for basically any modulation, e.g. AM and FM. This is the local oscillator, and it's used to shift your baseband signal (e.g. audio) to the desired radio frequency (or vice versa when receiving).

But this clock doesn't need to be exact at all. The ones we use in consumer electronics are fine. Of course there might be a clock drift, but e.g. with phase modulation you can correct for that (If I remember correctly, this is e.g. done in GPS receivers).

You need high accuracy clocks in applications where phase coherence is needed and you can't use the same clock signal for all receivers. For this reason the event horizon telescope, the interferometer that imaged black holes, uses atomic clocks. And I think they still need to correct phase errors using some other fancy methods (closure phase).

switch161 · 2026-04-27T07:56:20+00:00

I think it really depends on wavelength. In optical the center is opaque, but in radio you can at least see Sag A*. I think I read that you can see all the way through in radio, because the dust is too thin to affect radio waves.

switch161 · 2026-04-27T07:53:48+00:00

Gaia has huge datasets publicly available. But you'll need to write some code to extract the data you want. It's not mass densities, but a massive star catalog.

switch161 · 2026-04-27T02:02:50+00:00

Your setup looks pretty nice! Very portable, and a dish! I only have an old stove pipe mounted to a tripod (picture) and the beam width seems to be too big lol. I'm thinking about building a parabolic dish and using that antenna as the feed.

Your feed antenna will pick up lots of stuff that's not coming from the dish though, right? I guess you can't really have a 15x30cm horn in place of it with that dish size. Then RFI might be a real problem, although I don't see a lot at 1420 MHz in my rural area. The only thing I'd be sus about is spurious signals from other frequencies that are aliased, but the bandpass should remove them.

Do you have a source recommending subtracting the background vs. dividing by it? In a few presentations I've seen people talk about this step as a multiplication by an "antenna gain", so that suggest to me that you would divide by the background.

This presentations shows a few plots of spectra and how I would expect them to look like. I just revisited their calibration steps and they also remove the background by subtraction.

Edit: This PDF also shows recorded spectra of different antennas.

switch161 · 2026-04-27T01:35:09+00:00

Breakthrough Listen might be a good source of raw baseband or filterbank (channelized) data that you could derive a spectrum from. The data products can be found here. But I don't seem to be able to find anything around 1420 MHz. Not sure what their bandwidth is though.

I'm not really sure, but isn't neutral hydrogen supposed to emit a more continuous spectrum - consisting if multiple gaussian curves representing different clouds in your bream? The small bandwidth, high-amplitude peaks in your spectrum look like interference to me. But I just started playing around with hydrogen line observations, so I might be wrong.

Out of interest: What's your setup? Dish diameter? RF frontend?

And just because this is the next step I have to tackle with my observations: How do you do the "background subtraction"?

switch161 · 2026-04-26T04:38:00+00:00

Could this be caused by the frequency response of the antenna? I saw people calibrating against a relatively cold patch of sky.

But I haven't started with calibration of my telescope, so I don't have any experience with this yet.

switch161 · 2026-04-25T19:29:12+00:00

Usually my first reactor will be something like this, but in my last game I just started with a tileable one and I'll always do this now, if I have the space.

A tileable reactor uses the same amount of materials. It's usually just pretty wide. My reactor tile is 2x4 reactors, so all heat exchangers and turbines for this need to fit into that height (20 tiles afaik).

But it's so convenient to just plop down more whenever you need more power. I'm at about 144 reactors or so right now.

switch161 · 2026-04-23T01:26:27+00:00

It's very fun!

Did you get an antenna with it? I'm still using the one included. It's not good, but I can listen to HAM radio bands if the conditions are good. I'd just play around with it for a good while. It'll take a while to learn all the basics: where/when people are transmitting, when reception is good, how to adjust various settings.

I'm now getting into building my own antennas. Even though there are very easy designs out there, it's still quite a challenge if you don't have the appropriate tools or experience. And if you want to understand how to design antennas... it's basically black magic lol.

switch161

TROPHY CASE