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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6
votes
2answers
154 views

SSB offset determination?

Is there any algorithmic way to determine if the mixed frequency offset in an SSB SDR demodulator is wrong (too high or low), other than listening for funny sounding voices? (perhaps by checking to ...
1
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1answer
380 views

SDR demodulation of SSB

Is there any difference between demodulating LSB versus USB in software from IQ samples other setting the complex mixer frequency (LO) below or above the SSB signal frequency? (and excluding any ...
4
votes
2answers
434 views

Linux based SDR spectrum capture via CLI

I need to setup a Linux box to run unattended capture of about 10 MHz - contiguous worth of spectrum (Hardware must support between 500 kHz and 200 MHz) targeting voice (mix of AM and FM voice ...
2
votes
1answer
61 views

crt TV emissions

I have my Hack RF plugged in my TV antenna to have a cheap setup and I have observed on the spectrum analyser a signal (Bandwidth: ~400Khz) that is emitted by my old analog TV from 80ies. These are my ...
2
votes
2answers
163 views

RF scanner w/ graphic output

I debated putting this question on the electrical engineering forum vs. here. I settled on here since I figured many of you amateur radio experts have probably wondered about this too. I am ...
1
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1answer
157 views

transmitted FSK, sniffed something PSK-looking

I am transmitting a FSK signal on 433,941 ± 32 kHz at 19200 baud rate. From what I read I should be able to recover my signal with a a modem centered on my carrier and having a bandwidth of 32 × 2 + ...
13
votes
2answers
1k views

How do I receive ATV with GNU Radio?

How do I receive Amateur television (ATV) — e.g., NTSC in the U.S. — with GNU Radio so I can play the A/V in, e.g., the VLC video player? Are there any example GNU Radio block diagrams to accomplish ...
1
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1answer
924 views

RTL-SDR with SpyVerter - setup

I need some assistance in setting up a RTL-SDR with a SpyVerter upconverter, using SDRSharp. I have been using the RTL-SDR on its own with success. However, when I connect the SpyVerter (the side ...
3
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1answer
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 ...
3
votes
1answer
202 views

Build a HamRadio Friendly UMTS Module

I would like to play around with openBTS/yateBTS (experimental, no 24/7 run). What I would like to do is to modify a UMTS/GSM module or mobile phone so it operates in a frequency that can be used with ...
3
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0answers
755 views

OFDM spectrum, HACKRF, and GNUradio companion

I am trying to analyze the spectrum of wifi spectrum. I getting a good OFDM spectrum with my HackRF at 2.412 GHz (from my first QTGUI Sink). But I get nothing out of OFDM Receiver. I was wondering ...
2
votes
1answer
529 views

Gnu Radio with Funcube Dongle SDR

I am Trying to use Funcube Dongle Pro+ on Windows with Gnu radio companion with no success. My PC is detecting The Funcube Dongle Pro+, and it works on SDR#, But It doesn't work on Gnu Radio. I have ...
5
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2answers
710 views

How does rpitx generate arbitrary SSB data with a clock peripheral?

While it wasn't the first to do so, the rpitx software seems to be the most active and mature implementation of what its own comments call "a code fragment by PE1NNZ". The trick is explained in Guido'...
2
votes
0answers
85 views

Capturing the key fob signal with SDR [duplicate]

Is it correct to assume that not all the key fob signals have preamble section? I am playing around with bunch of key fobs and I am trying my best to capture their OOK transmitted signals with RTL-SDR ...
4
votes
1answer
1k views

SDR with the Raspberry Pi

I wanted to explore digital modes by connecting a Raspberry Pi via audio cables to a transceiver. However, I realized that thanks to the clock generator, the raspberry pi can produce RF signals ...
2
votes
1answer
193 views

Preamble of a garage door opener

After detecting the transmitted signal of a garage door opener with SDR, is it correct to assume the first repeating pattern of the signal is preamble? I only see two one and zeros with equal ...
0
votes
2answers
254 views

Why is this signal recognized as PACTOR II but not decoded?

I'm using SDR# and with virtual audio cable sound is piped to Wavecom W-CODE. W-code recognizes a frequency on 4 and 24 MHz as Pactor-II with 100% confidence, but he can't decode in terminal text ...
1
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2answers
697 views

HackRF Hardware

How does the demodulation done with HackRF? Is the mixed with IF and then the frequency spectrum is shifted to baseband frequency by sampling OR the frequency of the mixer in the hardware can be ...
0
votes
2answers
2k views

DIY 433MHz antennas from copper wire

I need to build two minimalistic antennas for RX/TX at ~433MHz. I have insulated solid core copper wire, but I need to make it perfectly straight. I was thinking of using the type of sticks you set ...
2
votes
2answers
408 views

HACKRF_ERROR_NOT_FOUND

I have connected my HackRF to my computer that runs Ubuntu and it was working fine until now. It gives me an error: ...
1
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1answer
67 views

short bit at beginning of tranmission

I recorded an OOK transmission (of a temperature sensor) and I'm trying to reverse engineer the recording to get the binary out with python. First I searched for the length of a bit. Therefore I ...
1
vote
1answer
336 views

Oscillators inside SDR hardware

Are the oscillators in SDR hardware (that are used to mix the input to sinusoidal waves) purely digital? In other words, is the sinusoidal analog signal is created digitally? For example getting the ...
2
votes
2answers
541 views

SDR hardware architecture schematic

Is this a good representation of the sound card SDR systems in which a receiver has a simple hardware detector producing two quadrature audio channels that can be fed to a computer's sound card? ...
5
votes
2answers
640 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 ...
4
votes
1answer
4k 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 ...
6
votes
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
580 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
337 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 ...
2
votes
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 ...
1
vote
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
909 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 ...
7
votes
2answers
425 views

How to calculate if low-pass filtering is sufficient?

An answer on this question Suggested method for boosting 0.05 watt transmitter up to 10+ watts? suggests putting a filterless 19dB amplifier between the HackRF (or similar general-purpose SDR) and a ...
9
votes
1answer
311 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 ...
2
votes
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-...
1
vote
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
vote
1answer
245 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 ...
4
votes
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 ...
2
votes
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?
3
votes
1answer
102 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
vote
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 ...
3
votes
2answers
303 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 ...
2
votes
1answer
286 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?
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 ...
9
votes
1answer
311 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 ...
3
votes
3answers
624 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?
2
votes
3answers
209 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 ...
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
211 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'...
2
votes
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?
2
votes
2answers
192 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.