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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21 views

2GFSK digital filter bandwidth calculation

I'm working on a S2LP from ST and I am configuring the RX digital filter. I need to calculate the bandwidth of the signal which has 2GFSK modulation. Do you think the code below is correct for ...
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1answer
78 views

How does an Airspy HF+ Discovery compare to a “real” radio?

I was looking for a secondary radio for RX only and I thought a SDR may be a better option. I read about upconverters but then I saw Airspy has a SDR with the upconverter onboard, and claims to have &...
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3answers
79 views

Practicality of SDR-based TX/RX

When it's not possible to be at the same location as a TX/RX appliance, some form of remote control is needed. There's basically two ways to TX/RX: classical radio appliance, with or without digital ...
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183 views

What is the current state of the art in CW filters?

In the 1970s I made a CW “filter” based on a phase locked loop that detected a specific audio frequency, and this drove an NE555 oscillator: the result seemed at first like a “zero bandwidth” CW ...
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1answer
66 views

Can these in-band spurs from rpitx be eliminated somehow?

I'm putting together a 2m NBFM transmitter/receiver combo using rpitx and rtl-sdr. During testing my low-pass filter I discovered that rpitx is generating spurious signals within and around the band (...
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How can quadrature mixing adjust the phase of all frequencies by the same amount? Can it be done in the digital domain?

This came up in some feedback I got when I tried to answer What is IQ in the context of SDRs? and revealed some of my own misunderstanding. Initially, I gave an answer something like (paraphrasing): ...
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42 views

Receiving and decoding RDS in GnuRadio

I'm new in radio, so I started with seemingly easy task - receive and decode RDS data. I use GnuRadio to understand the concept of working with RF signals. So according to standard RDS receiver looks ...
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1answer
33 views

Does DCS intefere with SDR reception?

Does digital coded squelch (DCS) interfere with the analog-to-digital conversion in software-defined radios (SDRs)? I noticed that I can receive normal transmissions with my SDR just fine, but I have ...
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156 views

What is IQ in the context of SDRs?

What is IQ, in the context of software-defined radios (SDRs)?
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78 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
108 views

Whats wrong with this radio signal?

I have a code that sends a beacon every 1 minute with a data-rate of 1200bps (BPSK-G3RUH). I do receive the signal using a custom software defined ground station that also decodes the beacon. After a ...
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100 views

Imaging with radio Frequency

Is it possible to image bones and tissues with radio waves (2.7GHz-5GHz) with a tiny radio frequency source and on one side and a receiver on other side which can image the data through a PC mediated ...
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Can the power output of a software defined radio be adjusted? [closed]

Some SDR transmitters have a very low power output. Can their output be adjusted?
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125 views

SDR transmit on more than one frequency

I'm new to SDR. Is it possible to transmit on more than one frequency, and if so what do I need? more on computer type network side one for each 800, 2.4, 5, 60 How can I get more than one SDR to ...
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1answer
80 views

Receiving different gain values on two RX channels on Ettus USRP B210

I am transmitting a continuous wave and using one USRP B210 with the kitchen_sink tool in order to save the received samples from two RX channels (v.3.15.0) When I look into the received signal on ...
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1answer
71 views

Can I get non demodulate IQ signals from WebSDR

I want to take a non demodulate audio signal from webSDR portals (http://www.websdr.org/). In order to try to feed these in DREAM DRM Radio software or GNURADIO. Could be cool almost try it for ...
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2answers
90 views

Advantages of IQ mixer versus baseband sampling SDR architectures?

What might be the advantages, if any, of HF SDR architectures that use a mixer between the ADC/DAC and RF, versus those that sample or generate RF directly at baseband with a fast ADC or DAC? Are the ...
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1answer
90 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
254 views

How to send DMR SMS using MMDVM modem or hackrf?

I have a baofeng DMR radio with SMS feature, and since there is not much DMR radio owners in my area I want to do something myself. The easiest thing I can do I thought is to send myself some SMS as ...
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1answer
87 views

Most accurate way to measure signal power with (cheap) Spectrum Analyzer

I am using an USRP X310 which is unfortunately not calibrated and the specs given are only very vague. Hence I would want characterize the device with first-order measurements. Unfortunately I only ...
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2answers
175 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
323 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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1answer
49 views

Shifting frequency outside of the band

In theory when i need to shift some frequency i just multiply that signal by some sin or cos wave with the right frequency and than apply LPF or HPF. But when there is a wideband complex signal with ...
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62 views

Is there any 2.4 GHz tuner ICs for SDR receivers?

I have a hackrf one sdr, which i use to transmit test signals. I am using ISM bands, so I can omit transmitting my callsign, checking correct sub band (FM, digital) etc. And one of most interesting ...
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75 views

what is the center frequency

in GRC for this source block ?
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1answer
84 views

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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1answer
76 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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1answer
88 views

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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3answers
196 views

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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3answers
217 views

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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51 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
69 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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2answers
261 views

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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41 views

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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1answer
60 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
192 views

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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197 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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43 views

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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45 views

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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2answers
149 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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102 views

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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2answers
100 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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79 views

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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156 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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1answer
174 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
343 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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113 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
2k 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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1answer
170 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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82 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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