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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Transmit on multiple frequencies with USRP using GRC

I am using an Ettus Research B200 with GNU Radio Companion (GRC) and I would like to transmit two signals at two different frequencies simultaneously. As a simple example, I would like to transmit a ...
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1answer
260 views

Homodyne vs heterodyne

Im not sure what is true, when I want to calculate it. First, the fact is that classic homodyne is used only in receivers. (I'm not talking about quadrature homodyne.) But I can't understand how the ...
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1answer
122 views

Pseudorange in VHF band navigation and precision phase tracking

I am thinking on what is the practical limit of precision for VHF positioning system (like currently obsolete and gone "Transit" system). It is well known how GPS receivers calculates pseudorange to ...
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2answers
84 views

How to determine the length of a symbol in a wave?

Is there a way to determine the length of a symbol in a wave? For example, how could I determine the length of a 0 or a 1 in a 2FSK wave?
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1answer
108 views

RF fading channel model?

What statistical or other descriptions exist regarding modeling of an HF-band RF fading channel? This is allow making (as in code my own software) lots of simulated test input signals for an SDR ...
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1answer
2k views

Decode digital signal (On-Off Keying) with SDR

I have a HackRF, and I'm trying to figure out the best way to decode an On-Off Key digital signal. I'd like to just run a script (specifying the frequency and sample rate) and have it print out the ...
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2answers
325 views

How to reverse engineer a proprietary FSK protocol

Assuming I wanted to reverse engineer 13FSK, what steps would I take to begin reverse engineering it? I have seen tools such as inspectrum and baudline that can help me view the raw signals, but I am ...
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2answers
320 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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1answer
2k views

SDR GnuRadio gr-dsd decode D-STAR voice

Hy i found this projekt: gr-dsd i compiled it and it seems to work so far. My problem is i don't find any Example just a Youtube Video (www.youtube.com/watch?v=DtkiC_Li_GI) wher it is used. Can some ...
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1answer
320 views

Confusion about SDR

I've just written code for the RTL2832 to receive and decode ADS-B packets (very cool!). I had some confusion about what is actually happening: Is the raw data coming from the USB dongle literally ...
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3answers
655 views

Any SDR radios that receive FM BCB

Are there any software defined receivers capable of receiving Regular FM broadcast band stations and displaying a waterfall of the band from 88 MHz to 107 MHz or a significant portion of that range?
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3answers
227 views

SDR for Spectroscope

I'm looking into getting a cheap SDR (perhaps the RTL-SDR RTL2832U) to use as a spectroscope, especially to test the frequency output of Baofeng radios. I currently have reason to believe that one of ...
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2answers
3k views

Can I send samples from the device made by myself to GNU radio?

I have two high-speed sampling devices that can use UDP (through 1G Ethernet) and PCIe to transmmit their samples, respectively. They are used to record signals I interested. These devices are made by ...
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1answer
229 views

What kind of modulation is this?

I was able to demodulate a signal I've recieved in gnuradio. Here you can see my flowgraph: But now I would like to be able to send data as well. But how should I modulate my data? As you can see I'...
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1answer
104 views

FUNcube Dongle antenna specs

What are the specs of the FUNcube Dongle antenna? I mean, how to fully describe only the antenna?
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2answers
196 views

Ettus USRP1 (or B100) instead of Funcube Dongle

Is it possible to use an Ettus USRP1 (or B100) instead of Funcube Dongle to receive cubesat signals? The Ettus ones are more expensive.
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1answer
143 views

Track cubesat with webSDR, is is feasible?

WebSDR is a Software-Defined Radio receiver connected to the internet. Here is being said "OK for HF but no good for VHF / UHF". I was thinking to use it for cubesat reception but given that the ...
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1answer
223 views

Warbler vs SoundModem

I'm trying to decode a BPSK 1200 (with no success). In this endeavor I tried both SoundModem and Warbler. The scenario here is the following: Ettus receiver + HDSDR with speaker plugged into mic via ...
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1answer
5k views

HackRF One — Expected 'hackrf_transfer -t' file format and its creation?

What file format does the HackRF One expect on the command line, using the -t option with hackrf_transfer? Also, how would I create or convert that format from a ...
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1answer
313 views

Can HDSDR perform the work of Direwolf?

I have a setup in which Direwolf is used in conjunction with a Baofeng radio to basically send data (AFSK). My app connects to the TCP server provided by Direwolf, send him some data which then is ...
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2answers
390 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 ...
4
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1answer
619 views

Can a WLAN device be used with GNU Radio?

Can I use my wireless ethernet card with GNU Radio? I have a Broadcom BCM4311 mini PCIe, and Debian / Kali 2.0 Linux.
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1answer
319 views

Connecting two SDRs together for one to act as a signal generator

If I have two SDRs like the BladeRF and I want to use one as a signal generator and connect them together do I have to attenuate the connections?
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1answer
296 views

How to generate FSK with Matlab and radio

I want to generate an FSK signal with a radio. My first idea is to generate an audio in which the high level is a 1 and the low level is a 0: This audio is then modulated by the radio with FM. In ...
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1answer
227 views

Losing Low Frequencies in AM transmission

I've been using a USRP software-defined radio to try to send an amplitude modulated signal to a very basic receiver, basically just a piece of wire as an antenna, over a very short distance. The ...
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1answer
1k views

How to detect a tone on an FM Frequency using an RTL SDR receiver?

I'm transmitting a simple tone which lasts 50 ms using an FM transmitter. I can see clearly this tone being received on my RTL-SDR device when I look at a spectrum graph (using GQRX). I need to call ...
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1answer
439 views

How to process signals captured using a SDR?

I saw that Oona Räisänen uses C and Perl to process digital signals: https://github.com/windytan So I was wondering if there is any book (or ebook) about how to use programming to process digital ...
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Why is dynamic range relevant for an SDR?

Sometimes I see dynamic range mentioned as a figure of merit for an SDR. For example, I know that the bits per sample used by the analog to digital converter can affect the dynamic range. Why do I ...
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2answers
538 views

Getting Started with Digital Modes on VHF on Linux

I am interested in learning about digital modes using 2m and Linux. I have a couple of older 2m rigs (HTX-212 and an old Yaesu) with no additional hardware, like a TNC. What current resources exist ...
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2answers
2k views

How to recieve a signal from multiple sources simultaneously (helical antenna)

I'm working on a system (theoretical at the moment) whereby I wish to receive data from multiple sources all transmitting at the same time. I've read that a helical antenna is capable of this. I'm ...
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3answers
2k views

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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2answers
1k views

What protocol or API does WebSDR use to stream audio?

What documented protocol or API does WebSDR use to stream audio over the internet? I'm interested in capturing a WebSDR audio stream using a small embedded device which has lots of audio DSP ...
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2answers
311 views

Center frequency spike on software radio for mismatched/disconnected antenna

A while ago I was using a software radio receiver to perform some antenna analysis. I left the spectrum display on while disconnecting the cable and noticed that when the cable was disconnected I ...
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4answers
563 views

Why are commercial SDRs so limited in operating frequency?

I spent a bit of time researching SDRs, mostly looking into the possibility of building an all-FPGA-based TRX. There are a lot of commercial ready solutions; some are cheap, some not, but they all ...
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1answer
247 views

What is a general procedure for aligning directional antennas?

I want to establish a microwave link (1.2GHz) between two stations using antennas with a directional radiation pattern. The stations have a clear line of sight to each other. Each antenna is attached ...
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1answer
2k views

Jamming with USB SDR

Could an attacker use a simple USB SDR dongle, as long as it is capable of transmitting within a certain range, to jam frequencies? I saw Lady Ada build the WaveBubble which is basically a dual-band, ...
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1answer
1k views

Suggested method for boosting 0.05 watt transmitter up to 10+ watts?

Long time ham operator here, new to this particular challenge - I have a software defined radio transceiver that I'd like to try and use to make contacts on HF, in particular 20-meters. Tuning ...
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1answer
3k views

Why doesn't GNU Radio Companion's wx Constellation Plot doesn't give me the clean QAM constellation I get from its Qt sibling?

Using a RTL2832U USB dongle, I set up GNU Radio to produce a constellation plot of APRS traffic on 144.8 MHz. The result is what I expected: So far, so good. Why not try the same thing using the wx ...
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1answer
198 views

SDR software support for National Instruments USB-4431 ADC?

I have an opportunity to purchase one or more of these 24 bit, 4 channel, 102ksps USB ADCs, but before I do I want to understand how difficult they would be to use with existing SDR software. Are ...
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1answer
2k views

How does SDR demodulation differ between wideband and narrowband FM?

What is the difference between software demodulation of an IQ signal between wideband FM and narrowband FM? Both seem to look at the 2nd difference in unwrapped phase angles of IQ samples.
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2answers
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Configuring an SDR for CW?

So I'm developing my own SDR software from scratch (I like to "own" the code). The channel between the RF-to-USB hardware and the software is 192kHz sample-rate IQ audio samples. The degrees of ...
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1answer
334 views

Why do SDR control apps have two frequency settings?

Why do many SDR control apps have two frequency settings, even when the app is designed or set up only for listening to or decoding one signal? Should the two SDR frequency controls be set ...
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5answers
7k views

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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2answers
180 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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1answer
667 views

Is there a rtl-sdr wrapper for the funcube dongle?

I would like to use some software packages, such as rtl_433, that are written with the RTL-SDR library with a FUNcube Dongle instead. Is there a wrapper that would allow the FUNcube Dongle to be used ...
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2answers
1k views

How might one realize a first order, two dimensional RF field antenna for HF?

I just coined the term "field antenna". It is by analogy to the lightfield camera or the soundfield microphone. Essentially, it is an antenna that captures not only the strength of an RF field, but ...
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2answers
511 views

What SDR software is available that provides internet control?

I plan to use a SoftRock Ensemble RX II to receive HF transmissions. I'd like to be able to use it wherever I am when I have a few minutes, though, so I'm wondering what software exists that would ...
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2answers
470 views

How is full duplex implemented without swamping the receive circuitry?

I've seen a few references to full duplex SDR radios, and I'm wondering how can one transmit and receive at the same time without overwhelming the receiver, and without heavy filtering such as the ...
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2answers
636 views

Can an amateur use cellular technologies with SDR?

Software Defined Radio is opening up many new possibilities for amateur digital modes. One family of technologies that interests me is cellular. 2G GSM voice/sms and 2.5G GPRS data has been proven to ...
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4answers
2k views

Is is possible to operate D-Star from a software-defined radio?

What is preventing a software-defined radio from transmitting the D-Star protocol?