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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4
votes
1answer
5k views

How to choose the right sampling rate and bandwidth for RTL-SDR dongle?

Receiving the frequency of 97.9 MHz I have a Terratec SDR dongle and I am trying to capture a radio frequency. The FFT window shows the frequency range from -500 to 500 KHz. Is there a way to ...
5
votes
2answers
665 views

Can I use old TV FM card as SDR?

I tried searching a lot before, but couldn't find anything about it; I have an old TV/FM card from an old computer, I wish to know if it can be used as an Software Defined Radio, and if yes, how? The ...
6
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2answers
3k views

Decimation to listen to FM radio with gnu radio

I am trying to listen to FM station using an SDR and GNU radio. I have followed this procedure Is there a reason that the decimation is done gradually? For example would it make a difference if I ...
5
votes
2answers
602 views

Software defined radio demodulation

I am trying to increase my knowledge on software defined radio and according to what I have read its hardware consists of three parts: Amplifier Tuner ADC I just wanted to make sure that my ...
4
votes
1answer
352 views

ADS-B for Trains?

Is there any kind of technology similar to ADS-B for trains? I'm aware of HOT/EOT/DPU messages, but as far as I can see these don't allow you to see its location. I'm specifically wondering about the ...
3
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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 ...
1
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1answer
145 views

SDR dongle and HamitUp for QRP Digi-modes

Will SDR, like RTL SDR dongle and Ham it Up converter, performing as well as traditional desktop HF receiver for digi-modes, like JT9, for HF low power (0.1 watt) long distance (500 to 10000km) ...
2
votes
1answer
940 views

33cm 5W(effective output power) tx amplifier for ATV (HamTV)

I am searching for a 5W effective output power TX amplifier that I can use with my BladeRF to send DVB-T Signals for ATV (33cm band). Can someone tell me on what things I have to look for when buying ...
2
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3answers
1k views

Improving VHF airband reception

I'm trying to receive VHF airband transmitted from a nearby airport via RTLSDR and having a hard time doing so. Obviously the stock antenna is useless in this situation. I tried building a quarter-...
4
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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 ...
1
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1answer
2k views

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 ...
1
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1answer
250 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 ...
2
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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?
8
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2answers
467 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 ...
3
votes
1answer
105 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 ...
1
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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 ...
2
votes
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 ...
2
votes
3answers
217 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 ...
9
votes
1answer
314 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 ...
2
votes
2answers
2k 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 ...
5
votes
1answer
220 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'...
3
votes
1answer
224 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 ...
2
votes
2answers
195 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.
1
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1answer
140 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 ...
2
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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?
4
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1answer
609 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.
2
votes
1answer
309 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?
3
votes
1answer
295 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 ...
10
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4answers
558 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 ...
9
votes
1answer
330 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 ...
6
votes
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 ...
11
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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?
10
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2answers
521 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 ...
7
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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 ...
5
votes
1answer
241 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 ...
3
votes
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, ...
6
votes
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 ...
4
votes
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 ...
6
votes
2answers
2k views

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 ...
1
vote
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 ...
9
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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.
2
votes
1answer
661 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 ...
9
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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 ...
7
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2answers
510 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 ...
10
votes
2answers
620 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 ...
6
votes
2answers
124 views

Mobile phone models that contain 2 way radio functionality

Are there any mobile phone models there that contain 2 way radio functionality?
4
votes
1answer
1k views

Installing cuSDR on Ubuntu 13.04

I've been trying to install cuSDR64 on Ubuntu so as to have a 4-receiver 4-display SDR setup. I found the Windows repository on svn here. But, it gives an error (check this question). The cuSDR home ...
10
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2answers
242 views

Which qualities/features does an SDR radio device need to be usable for Amateur Radio?

I know what things to note when selecting an analog amateur radio, but SDR devices have completely different specs, e.g. sample rate and resolution. What do I need to know about the device to make ...
2
votes
1answer
113 views

Model of a specific DVB-T tuner chip (circa 2013) that can be used to collect raw IQ samples

There is a common DVB-T receiver chip capable of producing raw IQ samples, which makes it a good device for Amateur Radio SDR experimentation. The chips is used in some DVB-T USB dongles sold around ...