Questions tagged [rtl-sdr]

Discussion related to the rtl-sdr project, which enables certain television dongles and other hardware to be used as a cheap SDR receiver

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44 views

How to get the “real” number of samples coming in an sdr

so I am fairly new to this SDR and dsp thing, I am working on a project that calculates the ppm and adjusts the offset, now I kinda got the idea of how to calculate the ppm after going through the ...
5
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1answer
223 views

Failing to detect Hydrogen line with 105cm dish

I've seen many examples of roughly 1 metre sized dishes being used w H+ sawbird and an SDR to detect and analyze Hydrogen line signal, and have been trying myself but can't seem to get anything beyond ...
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2answers
47 views

Not able to understand some operations in rtlsdr library in python

Here is the part of the program I am having problems with: samples = sdr.read_samples(16*1024) power, _ = mlab.psd(samples, NFFT=1024, Fs=sdr.sample_rate /1e6) ...
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2answers
297 views

Problem with sample rate

So I am working on a project that involves me to check real time difference between samples.I am fairly new to this so after a bit of researching I wrote a simple python script for it, here is the ...
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2answers
86 views

How do I set the RX frequency on a R820T/ R820T2 based SDR

My question relates to the specific programming of an R820T/ R820T2 based SDR for a specific frequency. I'm trying to build a self contained and auto initializing Raspberry Pi 4-based (ignore that ...
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151 views

GNU Radio FM Receiver does not work on Ubuntu 20.04 nor on Windows 10

GNU Radio v3.8 with Qt-GUI on Ubuntu 20.04 Before starting on something new I always test my setup with this GNURadio hello world flow graph which I know for sure, that it used to work. The other day, ...
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1answer
217 views

Heterodyning complex values in gnuradio

I have been working at educating myself on how SDR and GNU Radio works. In order to demonstrate heterodyning, I set up a flow-graph consisting of 2 signal generators, a Multiply block, and QT GUI ...
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2answers
196 views

rtlsdr - hearing an FM broadcast on different frequencies

There is an FM station in my city which transmits at 105 MHz. Today I discovered that I can also hear it quite well if I set the LO to 32.6 MHz and then shift the signal a bit. I'm using an rtlsdr ...
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0answers
85 views

Capture Uplink GSM packets using 820T2 and SDR

I am an extreme beginner with SDR. I am trying to use the 820T2 & SDR device to capture uplink gsm packets sent by my phone to the nearest Base Station. I have an Rx Monitor App installed on my ...
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1answer
84 views

Adapt old AvermediaTV DVB-T tuner as SDR

I want to adapt the DVB-T AverMedia TV Pilot" tuner as a software defined radio, but it is not built on a RTL chip, so the question arises, is there some kind of driver to use my tuner as a radio?...
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2answers
354 views

Broadcast signal deviating with time

I've been just scanning through the HF band at night seeing what all I can pick up, and I'm trying to figure out a particular signal. I'm using a VHF discone, which isn't ideal, but it works well ...
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1answer
83 views

How to track down and neutralize this apparent mixer creating noisy emissions around my signal?

When I transmit, it there seems to be something mixing and reflecting my signal. For example, when I transmit on 14.300 MHz, I see signals above my transmitted signal at at 14.500, 14.700, 14.900, etc....
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303 views

Implementing FM receiver using GNU Radio C++ API

This is my first ever experience with GNU Radio. I am trying to implement a simple FM receiver shown below with its C++ API. I seem to have pedantically deconstructed this receiver into its smallest ...
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3answers
331 views

Problem with RTL-SDR v3 dongle - unusable PLL

I own an RTL-SDR v3 USB dongle (official version from rtl-sdr.com). I've successfully used it for decoding weather satellites past year. I use (GQRX + Audacity)/(Arch Linux 64bit) + (WXtoIMG)/(Windows ...
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1answer
210 views

GNURADIO: What does the complex output of an osmosdr source translate to?

Warning: Noob question. I'm new to Software Defined Radio. My aim is to write a program that tells me the signal strength of a radio emitting source (I'll use three such sources and then try to ...
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2answers
249 views

HDMI to VGA adapter interference with 138.5 MHz carrier

(sorry for my English) I'm using the HDMI to VGA adapter on my pc, and receiving weather satellites on ~137 MHz with RTL-SDR V3. There was a problem: my VGA adapter creates a powerful signal, who ...
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1answer
162 views

How is gqrx producing audio?

How exactly is GQRX converting signal in any frequency to produce audio output? Is it actually done by gqrx or some other element of the stack?
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1answer
107 views

Ham radio listener is split up on old hardware

I'm trying to get a ham radio listener working with RTLSDR on an old Pentium 4. Unfortunately it is playing for a few seconds, then not playing for a split second, very split up. Is there a way I can ...
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2answers
357 views

Can I use a “bunny ears” TV antenna for RTL-SDR?

I'm trying to get into SDR and was planning on buying an RTL-SDR. For an antenna, I was thinking of using an old set of bunny ears I have lying around. However, I first want to make sure that they'll ...
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4answers
714 views

DIY SA612 + RTL-SDR HF receiver: good on laptop, but huge wideband noise on Raspberry Pi

I recently built a SA612 mixer for HF reception. I used an USB-frequency oscilator to shift the incoming frequency up by 28.8 MHz. I used a random wire antenna outside my balcony and connected it to ...
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2answers
74 views

Batch sampling SDR

I am using RTLSDR on macOS with Cubic SDR, it works great and is very intuitive. Now I want to do a frequency envelope analysis where I need to basically 3-d plot intensity versus frequency and time. ...
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0answers
172 views

Compare signal strength with Software Defined Radio

I want to compare field strength with an RTL-SDR dongle or HackRF One. With comparing I mean being correct relative to one another, like if I know field strength of one in mW/m^2 then I know the other....
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84 views

Demodulating ISO14443 (part of NFC) using SDR?

I'm looking for info on demodulating both sides of an ISO14443 communication using a cheap SDR, preferably an RTL-SDR (R820T2+RTL2832U). The application is passively monitoring an NFC exchange for ...
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1answer
110 views

Using dvb-t device as rtl-sdr

I am wondering if I can use that dvb-t device to listen 48-836 mhz? if it's no, why? thanks..
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1answer
850 views

how to select an SDR stick remotely from gqrx via soapysdr

I have a raspberry pi 3b on my roof (in a plastic box) with two SDR sticks attached to it. On the raspberry pi the "soapysdr" program runs. ...
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0answers
381 views

Capturing Bluetooth / WiFi on an SDR

I have a question, right before purchasing SDR for some tests: Commercial hardware for bluetooth (even Ubertooth) allows you to receive packets on a 1MHz channel. Which practicaly means that if you, ...
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2answers
3k views

GNU Radio does not run flow graph

I am sorry but yet again a question about GNU Radio. (I just started following some tutorials a couple of months ago and am learning about it. I am unfortunately not that proficient in it yet, but I ...
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2answers
387 views

How much power does an RTL-SDR draw?

Background: Last night (and the night before) I was playing with my RTL-SDR and GNU-Radio again. Working with my FM Receiver, (which was working previously by the way), I detected that last night I ...
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2answers
131 views

What to take in consideration when buying an RTL SDR dongle? (Amateur)

I want to buy an SDR RTL USB dongle and I'm looking for one on Amazon. I currently saw ones from 100 MHz to 1.7 GHz. I can't decide and I know almost nothing about radio, but I want to experiment ...
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230 views

No module named 'analog_swig' [duplicate]

I know guys you gonna tell me tat there is something wrong about GnuRadio or Pybombs installation. Well, this is my third time during the past 48 hours I reformat the OS of my mini pc fitlet2 mint ...
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0answers
140 views

No module named _osmosdr_swig [duplicate]

I am trying to run GnuRadio python code in my python web server and got the "No module named _osmosdr_swig" error. Please, what is the cause for this error? I know it sounds like so obvious that I ...
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3answers
873 views

VHF 50 Ω Antenna Over 75 Ω TV Coax

I have a 50 Ω VHF airband antenna which I’m planning to install in my loft, for use with a RaspberryPi-based RTLSDR scanner/receiver. I already have a UK-standard UHF/Freeview antenna using standard ...
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0answers
135 views

HackRF One and IoT overloaded?

I'm transmitting Z-Wave frames using HackRF One in loop, one frame every second. Has anyone clue why are some frames not transmitted? You can see several too long gaps between frames on Waterfall (...
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1answer
121 views

Unitrunker Receivers Not Displaying Fields

I've been playing around with RTL-SDR and Unitrunker attempting to get a police scanner working. I followed the tutorial here: https://sites.google.com/site/policescannerhowto/ Everything works as ...
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1answer
119 views

How can I improve my Es'Hail 2 reception?

I'm using an RTL-SDR to receive Es'Hail 2. My chain is as follows in order: 60 cm TV Satellite dish pointing 2 degrees off Es'Hail 2 Universal LNB (from TV company, not really a stable frequency). ...
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2answers
114 views

Tips for HF Antenna with house near AM transmitter

My back garden is very small - about 500sqft. I also live near an AM transmitter and requires an AM filter. I would appreciate some general tips on the best approach to receiving HF signals (Ham and ...
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1answer
2k views

RTL-SDR - rtl_fm: undefined symbol: rtlsdr_set_bias_tee

On a Raspberry Pi 3 B+ running Raspbian Stretch, when I run this command, timeout 115 rtl_fm -d 0 -g 49 -M usb -s 32000 -r 32000 -F 1 -f 50.293M outfile.raw I ...
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2answers
598 views

RTL-SDR dongle - what antenna should I use for APRS receive only?

I was following this guide to setup an iGate using an RTL-SDR dongle and a Raspberry Pi. It worked, and I have been able to test it by seeing some APRS packets from a separate transmitter (Arduino+...
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2answers
109 views

Digital transmission sounds

I'm playing with an RTL-SDR dongle and an LNA, on Linux Mint with GQRX and DSD A lot of frequencies show digital transmissions, which the DSD is not converting. I don't whether it is a format DSD ...
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2answers
186 views

RTL-SDR: command or script to obtain power and deviation of an FM radio station

My project is to monitor the power and the deviation of 3 radio FM stations, sending this values into a MySQL database. I can't stream directly the audio of the station, due to limited bandwidth. So ...
4
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1answer
934 views

FM Receiver on GNU Radio with RTL-SDR fails to produce any output sound

Here is how the FM Receiver I made using the GNU Radio Companion. (Basically, I was following this tutorial by VYE6Y on youtube.) FM Receiver Problem: Unfortunately for me, the GNU Radio gives no ...
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0answers
419 views

How to decode 2FSK signal with SDR?

I'm new to radio and SDR but, as a hobby project, I'm trying to decode a 2FSK radio signal received by an RTL-SDR that I sent using an SI4463 transmitter. The record file contains 3 packets, but I'm ...
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1answer
174 views

RTL SDR “dark region”

I'm new to RTL SDR, and I noticed there's a "dark region" (around 700-900MHz), and I haven't figured out why this is. My device's tuner is a Fitipower FC0012, where could I find the pinout and ...
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2answers
163 views

Reset the sps on symbol sync block GNU Radio

I'm using symbol sync block (symbol_sync_ff) on my project and i use many different sps values that i need reset on runtime. I'm trying to reset sending clock_est tag. Is this the right way to reset ...
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1answer
578 views

How to make a ferrite bar antenna for RTL-SDR?

I bought a RTL-SDR (blue one with little MCX antenna). I modified its Q branch, and can receive short wave radio with Degen 31MS antenna now. For MW, Degen 31MS antenna has a ferrite bar antenna ...
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3answers
2k views

How to attach a magnetic loop antenna to the 50Ω coax of an RTL SDR?

I'm planning to make a magnetic loop antenna mainly for receiving LW, MW, and SW radio broadcasting bands, as well as perhaps the 2.2km band and 630m band. (Not all of them with the same antenna, I'mm ...
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2answers
6k views

HackRF + Amplifier = HF/VHF QRP Radio?

Do you think it would work to combine a HackRF One and an amp like the following to create a QRP SDR? Link to eBay Output of HackRF is approximately 10dBm, which fit's this amp nicely... What is ...
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2answers
380 views

Advantages of IQ generation at Mixer Stage or within FPGA for SDRs

I draw two possible architectures for Software Defined Radios below. In the first architecture, I,Q signals are generated at the mixer stage and two ADCs are required. The FPGA down-samples the ...
6
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1answer
894 views

Cell Tower distance measurement

I am developing a hobby project to detect/measure the distance between my cell phone and a cell tower (GSM tower). I am newbie. I don't even know whether this is possible or not. I have following ...
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5answers
1k views

How important is the impedance and resonance of a receive antenna?

I'm very new to shortwave radio, as evidenced here: Can an antenna be too powerful for certain receivers? I want to build a longwire receive-only antenna for the HF frequencies. I've been using ...