Howdy!

I set up my RTL-SDR Blog v4 on my Windows Desktop and used AirSpy SDR with the SdrSharpPocsag Plugin to decode pages. On my desktop, it works perfectly, however, when I tried replicating the results on my second machine (which I use as a server, as my desktop gets turned off at night), I started running into a problem: the page output is gibberish.

I thought I might have cooked the dongle or something, but when I plugged it back into my desktop, I got the expected results.

- Desktop is Win11, Server is Win10.
- The antenna position is the same.
- Both use AirSpy SDR with the SdrSharpPocsag Plugin with the exact same parameters/settings/freq..

Working example from Desktop: https://i.imgur.com/oIqdrep.png
Broken example from Server: https://i.imgur.com/AIkGLw4.png

What I've tried:
- Reinstalling the software
- Reinstalling the driver on the Dongle
- Changing audio output in the server
- Changing freq. (all POCSAG freqs. seem to be jumbled)
- Restarting Server
- Changing USB ports (USB 3.0, 2.0 & front-panel vs. back panel)

I'm at a complete loss and would appreciate any insight anyone has to offer.

Thanks in advance!

I am getting a burst of static at the end of each call while monitoring local emergency services. I don't get this on my handheld scanner. Is this a settings issue on the channels?

Thanks.

Hi all! I am new to communication systems and have just started learning about it. I am working on the ground station for a CubeSat mission operating in UHF. To test GFSK Modulation-Demodulation, we are using an ADALM-PLUTO to transmit a vector of 9 bits and receive it using a RTL-SDR. I am attaching the images for the flowgraph I have used. The values used in the flowgraph are from intuition and may be wrong. When I directly connect the 2 Mod and DeMod blocks without using Pluto and RTL-SDR, the transmitted and received signal match but when I use the ADALM-PLUTO and keep the antennae close to each other (around a cm), the received signal seems similar to the transmitted one, but the amplitude keeps on varying between 0-200. When the antennae are kept far, we get a very noisy signal with large gain (~20). What am I missing?

Flowgraph I am using to do GFSK Mod-DeMod

Flowgraph without PlutoSDR Sink

Result without the use of PlutoSDR SInk

Result with the use of ADALM-PLUTO and RTLSDR (antenna kept far)

Result with antenna kept close-higher amplitude received

Result with anetnna kept close-lower amplitude received

Seen these on eBay and for the price they seem really attractive. I can't seem to find any reviews on them, so has anyone tried these? Any info would be appreciated. Thanks in advance. Link to an example: https://www.ebay.com/itm/316021649156?_trkparms=amclksrc%3DITM%26aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20240304162621%26meid%3D2e0fa7d3742843cc8574e64d603ba313%26pid%3D102020%26rk%3D3%26rkt%3D6%26sd%3D305945003225%26itm%3D316021649156%26pmt%3D0%26noa%3D1%26pg%3D2332490%26brand%3DUnbranded&_trksid=p2332490.c102020.m5276

I got a cheap RTL SDR dongle from aliexpress (just €13). I opened it up and the ICs are marked as RTL2832U and R820T2. I don't know if they are fake or not.

I installed SDR++ and tried to verify it's working. I could hear some FM radio between 90-100MHz.

I tried to transmit from my Baofeng UV-5R but Ι could see signals only at ~440MHz, nothing lower than that. What's going on here? Should I tweak any settings on SDR++ or is it faulty?

https://preview.redd.it/msbtfjmp7m7e1.jpg?width=1200&format=pjpg&auto=webp&s=432f910bb091f286410fa2ce41fc717f66c17577

https://preview.redd.it/y03fi9to7m7e1.png?width=1593&format=png&auto=webp&s=a4e27c1202032200abf105e63c450626813f91a0

I installed sdr trunk on two of my laptops and I put it on my desktop and it's doing this. I can't for the life of me figure out why. Is it soke sort of interference? I can run it on my laptop with the same sdr(s) with it sitting on top of my desktop while it's on and don't have this issue. All systems are windows 10 and I have a v3 and v4 rtl-sdr and I have the v4 driver insed. The pattern seems to change also.

So I have this 4 way USB splitter. One end plugs into a usb port, then a wire runs from there to this rectangular block that has 4 USB ports. I suspect it's just there for charging multiple objects, but I was wondering if it would be possible to plug in a USB based rtl-sdr device and read it off of that? So far, I haven't gotten it to work. Looks like this: https://m.media-amazon.com/images/I/51IFBKbuCnL._AC_SX679_.jpg

One goal for doing this is the rlt-sdr dongle seems to want to get loose from the port I have it plugged in. I think the splitter will fit more snugly into the port and the sdr dongle will fit better in the splitter's ports.

I also have more than one SDR device. Long, shot, but would I be able to, e.g., have an SDR connected to one antenna on one side of my living room, another SDR on another side of the room and get better signal?

I recently re-opened an old project that uses the linux RTL_FM command to open up a frequency and attach a demodulater (piped) on 169650000 hz and if you combine this with multimon-ng you can get all these locations, emergencies, all sorts of interesting stuff, kinda struck me as strange that in this time and age this data is still out there, knowing that data mining these days is a real thing just like Reddit closed of its own data for such, this data is completely open for the grab so to speak.

This works ONLY if you are in the Netherlands, but I think might work too for Germany or Belgium since we are pretty close to each other.

rtl_fm -f 169650000hz -s22050 | multimon-ng -a FLEX -f auto -t raw -

https://preview.redd.it/ocsk6dx9ih7e1.png?width=1493&format=png&auto=webp&s=9f72776065d1aab32965ba4d3b73c33f8dfb5a4c

You do need the corresponding capcodes database, I have a copy of that database (incomplete that is, you will see 'unknown' in the data), these capcodes are basically numbers assigned to specialized units, of either medics, fire fighters or police.

I wrote a script that connects the corresponding capcodes to a unit that belongs to this group, once you parse that properly you get something like this (real incident data):

{
    "timestamp": "2024-12-17 22:13:57",
    "capcodes": [
        {
            "capcode": "002029570",
            "organization": "Unknown",
            "region": "Unknown",
            "subregion": "Unknown",
            "description": "No description"
        },
        {
            "capcode": "000400491",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "Hoogezand",
            "description": "Commandant"
        },
        {
            "capcode": "000400752",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "Groningen",
            "description": "Delfzijl"
        },
        {
            "capcode": "000400754",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "Groningen",
            "description": "Delfzijl"
        },
        {
            "capcode": "000400771",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "Delfzijl",
            "description": "Blusploeg 1 / HV-670 / TS-631 / TS-641 / TS-650"
        },
        {
            "capcode": "000400775",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "Delfzijl",
            "description": "Blusploeg 5"
        },
        {
            "capcode": "000400779",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "Delfzijl",
            "description": "Kazerne Alarm"
        },
        {
            "capcode": "000400881",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "Usquert",
            "description": "TS-634"
        },
        {
            "capcode": "000400882",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "Groningen",
            "description": "Uithuizen"
        },
        {
            "capcode": "000400885",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "Groningen",
            "description": "Uithuizen"
        },
        {
            "capcode": "000400886",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "Groningen",
            "description": "Uithuizen"
        },
        {
            "capcode": "000401998",
            "organization": "Brandweer",
            "region": "Groningen",
            "subregion": "",
            "description": "Monitorcode"
        }
    ],
    "message": "P1 BNN-01 Ass. Ambu (afhijsen) Willem Barentsstraat Delfzijl 013050 013033",
    "frequency_info": "1600/2/K/A",
    "frame": "03.072"
}

As you can see, there is a lot of data in these signals, if you are interested in learning more, leave a comment. I can share my scripts, capcode file and give some pointers. Happy scanning :D

Hello!

Can anybody refer me to a step-by-step guide to where I could build a SDR that runs off a raspberry pi that can be used portably? I was thinking about buying the Uniden SDS100 but I did not want to spend $600 on it.

I think it would be really cool to build something with a very small display that’s portable and still looks like a handheld radio. I’m very new to Pi’s and SDR’s.

Thanks in advance!

Wonder if they can be used somehow, the nooelec v5 seems to be a streaming TV dongle repurposed for radio, made me wonder what could be done with the streaming TV box

Hi!

I want to buy one of these dongles to familiarize myself more with this and I was to eventually use it (or buy another one) with Home Assistant.

I have seen comparison of the RTL-SDR blog V4 with the Nooelec V4 in the past but I have seen no comparisons of the current models.

Which one would be best right now both in term of usability as sold and possible expansion in the future?

It looks like, in the past, the RTL-SDR had some additional advantages over the Nooelec while one of the major advantage of the Nooelec was its size, especially when one wanted to use more than one at the same time.

My Home Assistant box is a thin client so size is not as important as it would be for someone using a Raspberry PI...

Thank you and have a nice day!

I'm trying to study the ionosphere using the difference in phase shift induced by the ionosphere on the two different GPS frequencies (L1 at 1575.42 MHz and L5 at 1176.45 MHz). For this, I have one BladeRF micro 2.0 xA4 but I've read that the two RX channels must be set to the same frequency. I'd like to receive both signals at the same time, using gnss-sdr. Is there any way to go around this hardware limitation or do I need a second SDR?

So I have Gpredict setup to track some NOAA satellites, it is connected to SDR++ and in the Gpredict radio configuration I have AOS and LOS signaling enabled. Almost everything works fine, when engaged it automatically tunes into the right frequency for the upcoming satellite and tracks the doppler shift, it even starts a recording in SDR++ when an AOS event happens, but the problem is that it does not stop the recoding when LOS, So I have ended up with hours-long recordings because it was never stopped. The thing is, *sometimes* it does seem to actually work, but I have no idea what makes it work and not work. It seems to consistently start a recording just fine, but it just never stops the recording.

Does anyone have an idea what is wrong here? I currently have no idea if the cause is with Gpredict or with SDR++

One thing to note is that I did not find a Windows build of Gpredict on the official website (https://oz9aec.dk/gpredict/download.php), so the version I have is from Sourceforge (https://sourceforge.net/projects/gpredict/). I'm not sure how official the Sourceforge version is, both seem to be created by Alexandru Csete, but I don't see this build on the website so I don't know if it's up to date or not.

edit: I just realized the version I downloaded from Sourceforge is 2.3.37 while the latest release on GitHub is 2.2.1. So I guess I might have been too up-to-date (and was using a development build). Will update if the same thing occurs again with version 2.2.1. Also if anyone else has experienced and solved the same issue please share what you did, thanks everyone

update: Okay 3 recordings later, it seems like the 2.2.1 version is working properly. So if anyone else is looking for the Windows build of Gpredict then download the stable release version 2.2.1 from GitHub (https://github.com/csete/gpredict/releases/tag/v2.2.1)

Hello,

I need decode APRS via audio - and its only option, any rtl_fm and other things that takes entire RTL-SDR to itself is not a usable option in my case. And it MUST work under linux, windows is also not a option here

I tried via multimon-ng, trying setup direwolf, compiling QTMM - with every option was something wrong

multimon-ng:
I create a virtual sink via:
pactl load-module module-null-sink sink_name=aprs sink_properties=device.description=aprs

Setting aprs as output device in SDR++, setting radio to RAW or NFM, then trying to pipe it to multimon-ng
parecord --device=aprs --raw --rate=48000 --format=s16le |
sox -t raw -r 48000 -e signed-integer -b 16 -c 2 - -t raw -r 22050 -e signed-integer -b 16 -c 1 - |
multimon-ng -t raw -a AFSK1200 /dev/stdin

or via
parecord --device=aprs.monitor --raw --rate=48000 | multimon-ng -t raw -a AFSK1200 -f alpha /dev/stdin

But i doesn't have any output - just "Enabled demodulators: AFSK1200" and nothing more

with standard rtl_fm -f 144.8M -g 42 -s 22050 -l 20- | multimon-ng -t raw -a AFSK1200 /dev/stdin it just works, so it isn't problem with transiver

direwolf - i just cannot find option to make it work under pipewire - i'm not sure it is just impossible, or i just cannot find option to set it up

QTMM - i tried to compile it via QT creator, but this program is so old, that QT refuse to compile it v:

Do you have any ideas, recommendation or something i can do to make it work?

If you are in New Jersey are you scanning the airwaves for anything if so what are you scanning for anything in the mmWave or any other known frequencies that drones would use?

There have been some reports of stuff happening on channel 106.7 fm electromagnetic interference can anyone confirm?

I'm just curious

There's a lot of stuff going on there and across the country with these drones

Can any of you guys look into this?

Thanks

Does anybody know of any software (particularly android but any in general) that can run dual RTL-SDR dongles? I’m tired of waiting around for the SDR-STK so I’m trying to build my own. I saw this guy (Tom Nardi) build an inclosure for 2 SDRs and a USB hub. Apparently that works for him which means there’s software out there. Is there? Or do I need a hardware based thing?

Hello everyone. I just got my V4 stick and discovered TV Sharp wich lets me demodulate PAL TV. But when I execute it a window appears with the following message: "Cannot open RTL device. is the device locked somewhere?" Does anybody know what am I doing wrong?

Edit: Here's a screenshot of the software.

https://preview.redd.it/r35b58hrxu6e1.png?width=356&format=png&auto=webp&s=fd02cb990662efe16443a21795f2e9296f125520

Hi all. I had heard about XHSI and seen some videos and never managed to install it due to lack of precise instructions, but I had been looking for a long time for a manual that explained in detail the procedure to install XHSI with RTL-SDR. Now I have followed this step by step guide that I would like to share with you:

XHSI with RTL-SDR and rtl1090

Frequency: 445MHz
Bandwidth: 15kHz

Haven't found similar signals at https://www.sigidwiki.com/wiki/Database

Captured in Eastern Europe, RTL-SDR v4, if that matters.

https://preview.redd.it/3m15ofm6pt6e1.png?width=1596&format=png&auto=webp&s=aac5f30d2060ed60565b00b733cbd59a8c64d488

Closer look:

https://preview.redd.it/oc8xe8a9pt6e1.png?width=1596&format=png&auto=webp&s=cc57640f68ef2735d404d164fb647b9678564261

I have received the raw image in wxtoimage as attached. Can someone suggest to fix the issue.

thanks Balu

https://preview.redd.it/j28wu2hekr6e1.jpg?width=242&format=pjpg&auto=webp&s=662b869da7f0d1f7de26466e28f60dd13c98d85e

Using a known signal on a KiwiSDR which is booming in at S9+10 literally 2kms up the road from me. I can get snippets of voice that are about 5dBm above the noise floor but not consistently. I am running a 20m random wire antenna with a counterpoise. Using SDR-Console V3.3 and rtlsdr.dll from June 2024. Build date on dongle is 09/23.