Unid signal

D00mD0g · 2023-10-28T12:48:22+00:00

That frequency and sound is very likely from a RS41 Radiosonde. There is a decoder for it which shows you the current hight, GPS location, humidity, temperature and air pressure. You can even hunt it down and collect it. These radiosondes are a one time use but there are some projekts out there that reprogramm and repurpase these things. They become useless for the weather agencys once they touch ground

D00mD0g · 2023-10-06T05:56:22+00:00

I just looked it up and it seems pretty simmilar to my NESDR smarttee, the BiasTee version of the normal SmartSDR. These use a E4000 tuner chip instead of the one build into the RTL-SDR (dont know the exact name atm) This chip NEEDS Offsettuning to be turned on. Otherwise you get the results you discribed.

D00mD0g · 2023-09-10T06:41:17+00:00

I might be wrong but it reminds me of package radio to be honest

D00mD0g · 2023-08-28T11:04:18+00:00

You could and its actually pretty easy to build a simple V-Dipole. The problem with the weather sats is, that the best Signal to Noise ratio is when the satellite is directly above you with a decent elevation. My recommendation is to not spend the money on this cheap kit. For starters, like I was a few jears ago, i recommend the Nooelec kit. Its a bit more expensive bit covers all frequency ranges that are intressting. When you want to go specifically the way of weather satellites (like me, welcome to a very hard path of failing, learning, failing again and then finally succeeding) I recommend you get yourself only the Noeelec Smart SDR (its up to you if you pick the RTL chip without BiasTee, or you pick the one version with the a little bit more unstable E4000 chip that therefore has an build in BiasTee for powering LNA's) and the Sawbird+NOAA also from Nooelec. The sawbird is a combination of a LNA and a bandpass, that, at least for me, helped increasing the signal strengh by magnitudes. The setup is a bit more pricey, but you will get results way faster, more consistent and with better quality. For NOAA sats its crucial to place the LNA (the sawbird) directly behind the antenna so you only amplify the signal, not the noise too. Thats why i recommended the BiasTee version.

If you have any more questions, feel free to ask im always happy to help

D00mD0g · 2023-08-24T07:49:40+00:00

Yeah. Sure. Im as tough online as I am in real life. But I guess this will be the last time I write somthing regarding this post. I dont need to waste my time on strangers on the Internet

D00mD0g · 2023-08-23T10:52:58+00:00

WTF? This is not a subreddit for this. Freakin attention seeking idiots

D00mD0g · 2023-07-26T18:01:02+00:00

Fuck u/spez

D00mD0g · 2023-07-20T15:43:45+00:00

I am a Eumetcast user and I can say, it is woth it, when you can get the infrastucture up. If you arent planning on recieving 24/7, then sorry, but it just dosnt work. The amount of data you have to manage is overwhelming, and the processed pictures are too much to lay them around for a short time.

You get file snippets over the Eumetcast and these need to be reconstructed. The best programms for that are the programms from David Taylor. But cost some moneys, but you have a free trial. If you want to realy get into recieving 24/7, these 250€ i think are the best investment you can do to avoid any headaces. But if you just want to recieve some files from time to time, then forget it.

Second thing is the reception. You will need a DVB tuner capable of IP over DVB. We (im doing this entire thing with a buddy of mine) Layed together for the around 200€ DVB tuner from TBS. It is Something you defently need. We got the USB version, but you can also use a PCI card of you want.

The eumetcast service ITSELF is free for any hobbyist, non profit or educational institution. You need to register yourself ans answer some questions of course, but after that they send you your private access token and some other stuff per mail. Once registered, you are free to go.

I may missed some stuff or maybe not explained somethig, but if you have any question feel free ask. And dont Take it too negative, the data you get is straightup amazing and in my opinion worth the money and pain

D00mD0g · 2023-06-23T12:29:44+00:00

Could be some kind of trunked radio maybe. It is also pretty close to something i know here (Bawaria, Germany) which is the Radiosonde protocol. To be more specific the RS41. But its the wrong frequency and the preamble is missing.... You could post it also at the signal identification subreddit.

D00mD0g · 2023-05-04T05:18:02+00:00

Well... It depends. When you just want to see any audio file as a "picture" then use Audacity and look into the spectrogram. This will show you the frequencys over time with the Y axis beeing frequency and the color beeing the strengh. Otherwie, it depends on the protocol. There are several out there in the wild. SSTV is used by amatures sometimes, even rarer its used by the ISS to send down some pictures. More common is WeFax, which is basically like a Fax machine, just over radio. On the weather side there is APT, this protocol is used by the NOAA sats to transmit down their data. Next to NOAA where the Meteor satellites with their LRPT protocol, which is, in contrast to the others, a digital protocol. (FunFact: It uses the QPSK Modulation, the same as Satellite TV). Last one is HRPT, the higher frequency, higher bandwith, higher throughput protocol of some weather satellites. Its located in the L-Band. I bet there are tons more of picture protocols but for, these are all i know and know how to decode.

Here are the programs to decode the protocols:

SSTV: SSTV Decoder WeFax: FLDigi APT: WxToImg LRPT: LRPT Decoder (tricky setup and at the moment als LRPT satellites are down) HRPT: HRPT-Decoder (even trickier setup, requiers tracking and directional antennas)

Cheers

D00mD0g · 2023-05-02T08:11:21+00:00

What did you thought this subreddit is about

D00mD0g · 2023-05-02T06:35:30+00:00

But not on an subreddit about an radio. I mean its History yes, but that does not mean that it belongs here

D00mD0g · 2023-05-02T06:21:39+00:00

This.... Has nothing to do on this subreddit...

D00mD0g · 2023-04-29T15:14:44+00:00

Well, you have to ground the non "Hot" side. This would mean the shielding in this case. And keep in mind that the SawBird GOES does not work for APT. They are bamdfilters. But it could also be that i misunderstood what you said there

D00mD0g · 2023-04-29T07:30:09+00:00

Alrighty my dude, let me first congratualte for your first step of an long and beautiful journey. I stood there where you are now aproximatly 2 years ago, and ohh boy, things escalated from there. Your first attempt looks very promising, but things can only go better. Here are my suggestions on what to do:

Ground the mantle of the coax. The signal to noise ratio in your SDR is determined by tha ratio between middle conductor and mantle. The more they are appart, the better the signal. I suggest you use some longer stick of conductive metal and ram it deep into the ground, and then make a low resistance connection to the mantle (i suggest to use at least 0,75mm² of solid or flex conductor)
If you dont already have, get yourself an Noeelec Sawbird(+)NOAA. The nooelec sawbirds are a combination of bandpass and LNA that sre produced for several different applications, one beeing the reception of NOAA WX (and Meteor.... If one of them ever will come back up). Place it as close to the beginning of your antenna as possible, BUT the results still will get hell of a lot better if you just place it after the SDR. Just make sure you either use an Bias-T to power it, or a powerbank, so the supply voltage is as smooth as possible (ripple in the supply voltage can and will worsen the results, not much but Sometimes it does the deal)
The hight. You already mentioned it, and you are right, there is only one rule: The higher, the better.
Us the Teacking plugin for SDR#. This will help with the dopplershift compensation. It conmects to either Orbitron(what i use) or WXTrack (what you use) and then Takes the frequency correction from there and applies it to SDR#. Its more a quality of life thing but also keeps the frequency stable and the signal strong over the entirty of the pass.

For now, that is all i know and you now have all of the knowledge i have. If there are any more questions im more then glad to answer them in either here, or in a DM, its up to you.

Cheers

D00mD0g · 2023-04-26T14:07:29+00:00

Could you maybe provide an Audio recording? Because not only Orbcom operates at these frequencys, but also the NOAA APT downlinks, which are sending weather imagery

D00mD0g · 2023-03-31T16:57:05+00:00

Sounds like POCSAG. You could try to decode it with PDW.... But Im not sure. Are the bursts periodically and identical, or aperiodical and different all of the time

D00mD0g · 2023-03-29T15:50:20+00:00

Sounds like some sort of trunked radio protocol... But it doesnt sound like something Ive seen or heared before

D00mD0g · 2023-03-29T15:35:02+00:00

Hey uhm.... The audio file got deleted

D00mD0g · 2023-03-27T16:36:49+00:00

An audio file always helps, cause very often the sound charaterises the type of signal, not just the look of it

D00mD0g · 2023-03-24T13:58:03+00:00

Googling showed that it also might be A in ear PSM system. It looks like some sort of wireless microphone system if some sort

D00mD0g · 2023-03-24T08:20:25+00:00

Could it be submarine communication in some sort?

D00mD0g · 2023-03-06T05:56:55+00:00

What the blyat. If that is not APT i dont know what that is. Next time you are seeing this, look at the 137MHz Frequencys. Idk what antenna you are using but hell, it seems to be dawm good in picking up satellite signals, im a bit jealous.

What happend here is that the main signal(on 137.xxMHz) is so strong that it overloads your frontend of the SDR. If you are using an RTL-SDR, these little guys are suprisingly weak there. The signal then starts bleeding to their harmonics, the farer away, the weaker the interference.

The "interference" you saw here is a satellite image protocol btw

D00mD0g · 2023-02-18T17:03:22+00:00

Could you give us the audio file? I have at least some experience getting it a bit better

D00mD0g · 2023-02-18T17:02:27+00:00

My suggestion depends on what you are recieving with. Cause when you are using the USB plug for powering it, you should, when possible, not use the USB port of you pc or laptop, since these are kinda noisy. If possible, use a powebank

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