Questions tagged [software-defined-radio]

Radio devices that use digital signal processing in place of analog electronic components to manipulate RF signals.

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Turning raw APT data into an image

I apologize if this question is a little out of scope for the amateur radio stack exchange but I feel like it fit better here than over in any other forum. I have successfully parsed raw PCM data out ...
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305 views

How link between gnuradio and baudline?

I want to create a sink block in GNU Radio which transfers the signal to baudline. My purpose is viewing SDR's received signal online. How should I program this block?
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audio problem with SDR on MacOS

I'm experimenting with SDR on MacOS High Sierra. Trying both CubeSDR and GQRX and experiencing similar issues with both. The applications seem to work, but the audio is choppy and chipmunk-like. ...
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42 views

Gnuradio AM broadcast receiver distorted audio

I have been trying to build a gnuradio AM broadcast receiver, but without success. I have tried a lot of combinations, but all of them produce a very distorted audio. I have an NBFM receiver using the ...
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85 views

How to output a CW tone or a Broadband Noise in GnuRadio?

Kindly, can anyone show me how to output CW tone or a Broadband Noise in GnuRadio in a sort of simple flowgraph if possible? Update: So, what I did is I tried not to overthink the whole issue here ...
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What is the typical latency of a SDR setup running on a desktop computer?

It's well-known that the signal processing of an SDR adds a significantly amount of latency, the SDR software on the computer adds more latency due to data buffering, FFT, decoding, demolutaion, audio ...
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305 views

Does anyone repair Flex radios other than Flex Radio?

A local ham that I have an evening sked with on 75m (Paul, W0EBV) sent his Flex 5000 SDR transceiver to Flex Radio Systems to get it repaired a few months ago. However, it seems that Flex is either ...
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ARRL handbook as a reference for all your radio learning needs?

Looking to take up learning understanding everything from basic electronics to how today's wideband radios work, so that I can build my own radio systems (not just ham radios), and talk radio concepts ...
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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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38 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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How is a crossed-ellipse display generated from FSK?

What is the algorithm or circuit needed to generate a (vintage?, retro?) crossed-ellipse display from RTTY and/or 2FSK signals? (as per the (obsolete?) questions in some FCC exam pool) (assume ...
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Gnuradio loopback flowgraph is not working

I found the below uhd_two_tone_loopback example (which is one of the gnuradio provided examples) and I am trying to run it, it runs but I can't receive signal. EDIT: I mean when I run the program I ...
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55 views

Controlling the number of samples

In the below simple qpsk_tx_uhd flowgraph I am trying to create a slider to control the number of samples but got a bit confused with which parameter I should be ...
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3answers
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Under what circumstances does intermodulation become an issue in a filter after LNA setup?

I'm reading about using software-defined radio for picking up ADS-B signals at 1090MHz. There is this blog which considers (among others) a setup as follows: ...
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SNR measurement for a BPSK/QPSK signal

I have created a software (gnuradio) that performs modulation/demodulation and supports a number of modulation schemes and error correcting codes. I'm in the process of evaluating the BER vs SNR for ...
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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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3answers
1k views

SDR CB Transmission

I have a CB radio and I occasionally mess with a cheap SDR Dongle I have. I can pick up CB transmissions no problem but would like to be able to broadcast from my SDR. Is there any way to do this? I ...
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What the difference preamble and access code?

gnuradio packetize using access code for start sync packet, but another example attach the preamblee, so what the differences preamble and access code ?
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A gnuradio program that can output some arbitrary waveform read from a file containing I/Q values

I am trying to figure out how to create a gnuradio program that can output some arbitrary waveform read from a file containing I/Q values. I would highly appreciate any guidance in this topic. Simple ...
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How FEC works on GNU Radio

I am new to GNU Radio. I need some reference to how to use FEC block in GNURadio. When I try to make encoder and decoder without modulation, its work as well, but when I using modulation and add ...
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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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SDR: Quadrature demodulation vs direct RF sampling

I see that many SDRs use a quadrature demodulator and sample I and Q signals. But is it possible to downconvert the RF signal instead, sample it with only one ADC, and get the same capabilities of ...
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338 views

What is “Billion Code” for garage door openers from around 1996?

I've been trying to "hack" my garage door using an SDR (LimeSDR) for a high school physics project, and I have run into a snag. When I look at the signal and demodulate it using ASK in Ultimate Radio ...
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Trouble with osmocom source

I'm having trouble running a simple flowgraph with an osmocom source and a qt gui sink. If I run the file with a waveform generator instead of the osmocom source, all is well, the plots appear as they ...
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1answer
130 views

Merging gnuradio generated python code into the Python web server

I am trying to figure out how I control a Software Defined Radio over a network, and stream the received baseband samples from my remote hardware back to the gnuradio. What I'm trying to do here is, ...
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350 views

No module named 'gnuradio'

I encountered with the "No module named 'gnuradio'" error while I was trying to run GnuRadio python code in my python web server. And this is my gnuRadio generated code: ...
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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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1answer
117 views

Can I capture stereo IQ signals from WebSDR?

When I set my sound device to record from the monitor/loopback source, I can capture the signal from WebSDR in my browser in an application like Audacity. Looking at the captured signal more closely ...
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1answer
61 views

SDR as an oscilloscope

Can a SDR be used as a general purpose AC oscilloscope with appropriate attenuation at the front end. Have in mind a capacitor to block DC voltages, large resistor say 10 Mohms to limit current and ...
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44 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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2answers
379 views

BPSK raw data aquisition with HDSDR and FLDIGI

I was playing with HDSDR+ExtIO and Ettus USRP1 to track a BPSK signal. In the end I successfully heard the signal. But I would like to see the data, I mean the raw data (HEX values). For that I tried ...
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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
118 views

How does one know how a signal has been modulated

I am trying to intercept signals from a drone remote controller and decode them. Before I can do this I need to demodulate the signals. All I have is radio data from the transmitter's operating ...
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Why is GNU Radio “stuttering” with this flow graph?

I have a GNU Radio Companion flow graph, where I have the following connections: 440Hz cosine wave throttle block audio sink All of the above blocks use the same sample rate (48KHz). When I ...
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1answer
58 views

How narrow-band can a DVB-S2 signal be?

Using software defined radios I can generate and demodulate a DVB-S2 signal live. I'm wondering if I can use this to send single pictures over the air using as narrow BW as possible. Using QPSK and a ...
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1k views

How to best connect an FM transmitting GPIO pin to an antenna?

I'm trying to use a RaspberryPi3 as a FM transmitter, using pifm and/or PiFmRds to send audio in 88-108 MHz band. The RPi can then use the GPIO-4 pin to transmit between ...
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Remote SDR on the internet other than WebSDR?

Besides WebSDR, what remote Software-Defined-Radio stations (for shortwave or amateur bands) might be available for open public access over the internet? What protocols do these SDR stations use to ...
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1answer
72 views

Problem recording morse with sdr#

I have a problem with recording SWS-morse using SDRSharp and RTL-SDR. I want fixed gain, not audio automatic gain control. The problem is that all signal but the weakest will cause the recorded audio ...
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69 views

Using Satnogs' *.ogg files in GnuRadio flowgraphs

I want to use the *.ogg files available in Satnogs' database to test demodulation software for several satellites (using gnuradio). Can i use the ogg file source (available in gr-satnogs module) and ...
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1answer
119 views

Why does SDR# sound better than SDR console?

This is kind of odd. I just got my first SDR receiver and I noticed that one application (SDR#) sounds a lot better than another (SDR Console) when listening to stereo FM broadcasts through the same ...
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1answer
109 views

Where does this common spurious transmission come from? Is there a quality difference?

I decided to see what my ham transmissions look like on an SDR and was kind of shocked to see how much leaks out. The waterfall display is split between two handhelds during transmit. There are a ...
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54 views

How to limit frame transfer in Gnu Radio Companion?

I have as source a bit frame, then I modulate it, to finally transmit it with my HackRF. I can receive and decode it normally with another HackRF. However I would like to limit to a number of frame ...
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177 views

What happens when I and Q are switched?

In https://ham.stackexchange.com/a/1068/9 it's shown that one can use $$ r = \sqrt{I^2+Q^2} $$ to decode AM signals from a direct conversion receiver. It appears that, in this particular case, I ...
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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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116 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 ...
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216 views

How I can build dvb-t/dvb-t 2 transceiver?

I need dvbt2 transreceiver. I tried gnuradio with https://github.com/BogdanDIA/gr-dvbt. The "apps/dvbt_tx.grc" is working. But, video cannot transfer flexibly. On gnuradio flow, I adjust multiple ...
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3k views

Signal Source Block of GNU Radio

GNU Radio has a Signal Source Block which considers a set of variables to produce an output, namely sample rate, frequency and amplitude. In signal processing, we define a basic waveform by its ...
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198 views

Long range communication with just 1W of power?

Is it possible, and how can I setup communication between stations 1000km apart from each other by using just 1W of transmission power? By communication, I mean: It can be text based It can be very ...
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314 views

Is there a name for the demodulation technique described here using the parallax propeller?

Is this a recognized SDR technique with a name, or is just a combination of DSP, r/f techniques ? I asked the author, but didn't receive an answer, perhaps because he thought it was "obvious" (not to ...
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1answer
133 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 ...