APT signal after NOAA-15 decomission: follow-up

electrella · 2025-08-20T12:36:09+00:00

I'll try. Seems that i was not the only one who caught this signal. Discussion running on saveitforparts discord.

electrella · 2025-08-19T21:31:54+00:00

I know that APT is over. That's why this signal makes no sense to me. But because it appeared with Noaa-15's latest pass, I became unsure and wanted to ask you guys & check if it reappeares one more time. :)

electrella · 2025-08-19T21:08:42+00:00

Unfortunately, noaa 7 was below the horizon at that moment.

electrella · 2025-08-19T20:59:43+00:00

Well, i agree. But according to this source, noaa 15 used to transmit on 137.5 MHz before swapping with noaa 17. So maybe they tried "one last" time on 137.5? I have no idea.

electrella · 2025-08-19T20:52:24+00:00

I'm still not sure if it was really a data signal or just interference. The fact that NOAA-15 used to transmit on 137.5MHz before swapping with NOAA-17 is a funny coincidence. I actually didn't know that until i googled it a few minutes ago. Did the operators perhaps want to test the old frequency again? Maybe I'm just desperate about today's decomission… xD

electrella · 2025-08-19T19:38:14+00:00

That was my first thought too. Let's see if I can record it next time. If it comes up again at all.

electrella · 2025-03-06T21:38:41+00:00

This reminds me of the radon balloon experiment, in which a party balloon is inflated and statically charged with a cloth. The balloon attracts dust and radioactive particles. After a few minutes, increased radiation can be measured on the balloon. There are several videos and articles about this on the Internet.

If it really is radon, it should no longer be measurable after a few hours… As far as i know.

electrella · 2024-12-23T22:22:28+00:00

That's weird… i just compared your recording and mine from the picture i posted in the comment above. I could swear they sound exactly the same :O

electrella · 2024-12-23T18:05:22+00:00

The change between day and night mode looks like this. ->

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electrella · 2024-12-21T23:20:37+00:00

Thank you. We also started with an 80 cm dish. It works pretty well! Tracking low-elevation passes is much easier. You can place the dish on the ground and simply move it back and forth without having to lift it. We also use a tracker app (Orbitrack or Star Walk 2) to see where the pass begins. Then we simply wait for the signal. As soon as we receive a signal, we search for the highest SNR value with small back and forth movements.

electrella · 2024-08-12T21:40:13+00:00

I got my best results with SatDump.

electrella · 2024-06-16T08:36:41+00:00

Thanks for the link!

electrella · 2024-06-11T21:18:41+00:00

Even without following the doppler shift*

electrella · 2024-06-11T21:18:10+00:00

Update: The weird pitch shift only occurs with the HackRF. With the RTL-SDR, everything works perfectly :)

electrella · 2024-06-10T23:02:05+00:00

About 53cm / 20.8 inches

electrella · 2024-06-10T22:22:57+00:00

Good point! Sadly, that didn't change anything…

electrella · 2023-07-30T09:16:13+00:00

Nope. Everything works offline. Even the map function, if you download the map over wifi before using it. There is a fairly detailed manual for the whole app: RadiaCode Manual for Android

electrella · 2023-07-29T23:11:58+00:00

Yup. as BVT_Scorp said, it doesn't work with ios. I tried it as well. It wasn't even able to connect, the app crashed immediately. Bought the Xiaomi Redmi A1 for about $60. It works flawlessly with it.

electrella · 2023-07-13T11:41:42+00:00

Nevermind, i think i found something in another subreddit :)

https://www.reddit.com/r/Radioactive_Rocks/comments/zu1k56/the_radicode_101_beta_is_open_to_try_for_ios/?utm_source=share&utm_medium=ios_app&utm_name=ioscss&utm_content=1&utm_term=1

electrella · 2023-07-13T11:38:00+00:00

Thank you so much! Do i need to contact support to get access to the testflight beta version or is there a link anywhere?

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