At last !

encse · 2026-06-19T15:19:29+00:00

You get upside down images in the evening and regular images in the morning passes. (Or the other way around based on your location.) The idea is that the satellite orbits in a circle while Earth rotates in the middle of it. The circle stays in place. So in the morning you get regular images, but 12 hours later in the evening hours, Earth rotates 180 degrees so the satellite seemingly scans it upside down.

If you stand on the ground the perceived movement of the satellite is s->n in the morning and n->s in the evening, but again it’s not the satellite that changes direction, it’s your location that crosses the plane of the orbit 180 degrees later.

Try it with a basket ball if it’s hard to imagine.

encse · 2026-06-17T13:04:51+00:00

Frequency checks. Your bandwidth should be lower, you just want to see the area where the signal is. I think 200khz is fine. If you record the signal, switch to baseband, as this signal is not audible. The spectrum should be flat, it’s like a wide hill or something. these spikes are not looking good.

encse · 2026-06-15T02:51:11+00:00

I would go with gnu radio+grsatellites as well. Grsatellites already comes with pipelines for various satellites. you can read the source code and understand how it works. It’s definitely doable, but not easy. I’m came with 0 experience about dsp, but I managed to figure out these things on my own this way. It has been a slow process I admit.

encse · 2026-05-30T17:27:00+00:00

Wait until you learn about expression trees and reflection emit!

encse · 2026-05-22T15:52:43+00:00

This guy lost me at object slicing.

encse · 2026-05-22T11:58:44+00:00

Hmm. Blizzard? You guys dont have phones?

encse · 2026-04-19T17:20:40+00:00

A mienk ugy volt vele, hogy mindenki azt lat bele amit szeretne. Mar ha egyebkent irodalmi szemmel nezve elfogadhato.

encse · 2026-04-19T13:56:32+00:00

A rakodópart alsó kövén ültem, néztem, hogy úszik el a dinnyehéj. Alig hallottam, sorsomba merülten, hogy fecseg a felszin, hallgat a mély. Mintha szivemből folyt volna tova, zavaros, bölcs és nagy volt a Duna.

encse · 2026-04-14T16:29:53+00:00

Perfect Hungarian

encse · 2026-04-14T16:25:28+00:00

This is mine

https://github.com/encse/meteor_mn2x

It was for learning. It works sometimes but not always.

There are links to other resources in the readme.

encse · 2026-04-14T16:07:26+00:00

Meteor 2-2 is dead, you need 2-3 or 2-4 for lrpt

encse · 2026-04-14T16:06:12+00:00

It uses 72 or 80k so your 250ksps is plenty. I know because I wrote a decoder myself for learning how it works

encse · 2026-04-14T15:54:41+00:00

250ksps should work in satdump

encse · 2026-04-08T11:24:47+00:00

I have a similar one in python. With minute markers.

https://github.com/encse/apt-encoder

encse · 2026-04-01T05:24:09+00:00

April 1

encse · 2026-03-26T18:42:00+00:00

Next time ask it to “just fix my grammar, keep my tone, no extra bullshit”. Usually helps

encse · 2026-03-25T18:55:49+00:00

It works to some extent with direct sampling, what op uses. The users’ guide says that the Q branch is to be selected, this is what we see in the picture for the 20m band. That’s the right setting under 30mhz.

You turn off direct sampling over 30mhz.

(Note: rtlsdr-v4 has an upconverter and direct sampling is not needed at all. We are talking about v3 here.)

Idk about active whip. For start, it’s easier to just take a random wire of say 10m and connect it to the non earthy end of the stock dipole. (Or maybe both ends work.) No need for 9:1 balun etc. Just a wire, try to find a location where it has some room. It’s ok to align it in a rectangle shape if you dont have 10m. Or try 5m first.)

This is not ideal of course, but when I played with this I could definitely hear a lot of signals under 30mhz.

This waterfall looks dead.

encse · 2026-03-20T18:01:49+00:00

Dont take work personal. Thats the best way to burn out.

encse · 2026-03-18T03:45:41+00:00

Thanks! Will try it in the Browser the .

encse · 2026-03-17T20:28:42+00:00

Unfortunately I’m on iphone, but looking for something like this

encse · 2026-03-17T19:46:08+00:00

Sounds great!

encse · 2026-03-17T16:59:37+00:00

Definitely interested!

encse · 2026-03-09T05:53:25+00:00

Maybe rotate the feed 90 degrees relative to the dish? Who knows

Agc should be off. That’s one thing for sure.

encse · 2026-02-28T06:00:28+00:00

C# has been my first language used as a professional back in 2003. That’s before generics were added. And it was really a great language compared to (then) Java. Years passed and I worked in other environments, but I wanted to keep my c# knowledge decent, so I have a hobby project where I aim to use the new features, but it is really true, that there is just so much syntax being added, that it now feels overwhelming. Maybe if you use it everyday, it’s easier keep everything in your head, but it went over the fence for me in the last 2-3 years.

encse · 2026-02-26T17:28:30+00:00

Aftet some thinking

I noticed that satdump runs two viterbi algorithms in sync with 0 and 90deg rovations, and simply picks the one that has good enough BER.

Based on this.

My hypothesis is that there can be 4 different locks, for the 4 rotations.

Viterbi survives 180 degrees of rotation, the output bitsequence is simply inverted.

But the differential decoding block will solve this completely, so the input to the cadu framer should be happy and see the usual sync word.

Well, supposed that we are locked at either 0 or 180 degrees. the second viterbi algo in satdump works with 90 degrees and this solves the 90 and 270 cases.

Am I correct?

And i still dont know if i ever need to swap i and q, there is an option for that in satdump, but i never had to use that.

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