[HN Gopher] Software-Defined Radio for Engineers (2018) [pdf]
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Software-Defined Radio for Engineers (2018) [pdf]
Author : Tomte
Score : 153 points
Date : 2025-03-10 17:40 UTC (5 hours ago)
(HTM) web link (www.analog.com)
(TXT) w3m dump (www.analog.com)
| Sanzig wrote:
| In terms of software-defined radio learning resources, I can
| wholly recommend PySDR: https://pysdr.org/
|
| It's written by one of the GNURadio developers, but it uses NumPy
| and SciPy instead so you really get a feel for the low-level
| algorithms. Concepts are well explained and build on each other
| from module to module.
| aswanson wrote:
| Good resource, thanks.
| jdc0589 wrote:
| It's really easy to forget how complex SDR is, and how much
| expertise it really requires to fully understand if you need to
| write receivers/processors/filters yourself. There's a TON of
| great stuff out there for hobbyists that just want to get some
| cool stuff working though. I tried my hand decoding a soil
| temp/humidity sensor broadcast and was quickly reminded how
| complicated it can be for an initiate.
|
| I know almost nothing about actual SDR, but I've got a cheap SDR
| receiver/antenna inside a glass basement door that receives
| temp/humidity data from ~10 433Mhz transmitters in various rooms
| in my house + outbuildings, and a weather station that reports
| temp/humidity/lignthing strikes/rain amount/wind speed+direction,
| and lux. All that goes to an influx DB instance, and has a set of
| graphana dashboards built on top of it. Took me a couple evenings
| to get set up, and now I've got real time + historical
| environment data about everything I care about at my house;
| including high humidity alerts in rooms with dehumidifiers,
| freeze warnings for a crawl space, and a bunch of other stuff. It
| has been wildly reliable.
| dhr wrote:
| I've just started getting into SDR - what receivers and
| transmitters are you using? Would love to give a similar
| project a go at my place!
| Jtsummers wrote:
| RTL-SDR is an inexpensive way to get started, only a receiver
| though. Transmitters are more complicated (legally) since a
| lot of spectrum is off limits without a license in most
| jurisdictions. They have a kit with a couple basic antennas
| to get you started.
|
| https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
| Joel_Mckay wrote:
| The RTL-SDR dongle with GQRX is highly recommended, and go
| well with a NanoVNA.
|
| https://www.tindie.com/products/hcxqsgroup/4-nanovna-v2-plu
| s...
|
| LimeSDR are a bit more involved, but like most SDR
| transceivers still need band-pass filters and power
| amplifiers to perform well. Works well when combined with a
| GPS locked 10MHz GPSDO like a BG7TBL. =3
| staplung wrote:
| If you want to decode transmissions from common weather
| sensors, be sure to check out rtl_433
| [https://github.com/merbanan/rtl_433]. If you have and RTLSDR
| dongle, it should just work.
| flyinghamster wrote:
| I've played around with Gnu Radio, and even though I've been
| able to do some very sophisticated things with GRC, I also
| realize just how little I really know. Part of that is that the
| math makes my head spin. I'd be lost without those blocks doing
| a lot of the work for me.
| bob1029 wrote:
| If you are serious about getting into SDR, having background in
| DSP can take you very far. Most of the painful SDR dragons are
| based in stuff that was optional at university time, but is
| otherwise not that hard to pick up once you know it exists.
|
| Understanding the frequency domain, why it's useful, and how to
| get there & back, is like 80% of the puzzle.
| _benj wrote:
| I think as a counter point, Michael Ossmann, the creator of
| HackRF One has worked really hard to make it a lot more
| accessible.
|
| In one of my favorite YT videos ever he talk about how he
| design RF PCB. The point of it is kind of like, the field of RF
| and SDR is incredibly deep and complicated, but at the same
| time, most filters/mixers/amplifiers and everything else needed
| for making an SDR are ICs that one can buy from Digikey and put
| them together (or likely have assembled).
|
| So, not denying how deep SDR can be, but it can also be
| accessible with enough effort!
|
| https://www.youtube.com/watch?v=TnRn3Kn_aXg
| atulvi wrote:
| > weather station that reports temp/humidity/lignthing
| strikes/rain amount/wind speed+direction, and lux
|
| Do you get this information from radio waves? would love to
| know more about your setup.
| hnuser123456 wrote:
| Apparently 433mhz environmental sensors is a whole category:
| https://www.amazon.com/wireless-433Mhz-weather-sensors-
| Home-...
| Jtsummers wrote:
| They're using weather stations that broadcast on 433MHz
| around their property and receive those messages with their
| SDR, then they pipe that into their database and display
| system.
| KeplerBoy wrote:
| Not OP but the idea is simple: You put transmitters somewhere
| outdoor (or wherever you want to measure) plop a battery in
| there and be set for a few years.
|
| Such weather stations were really commonplace 20 years ago, I
| remember my grandparents having a sensor outside and a basic
| LCD display in the kitchen displaying the outdoor temperature
| and humidity. These days we want that data digitally on our
| phones or home assistant so you need a receiver that talks
| TCP/ip and runs a real os. That's where the SDR comes in to
| bridge the gap between primitive RF Tech and modern
| computing. Of course you could also put an esp8266 outdoors,
| which natively talks wifi, but then you lose range and your
| battery life goes from years to weeks.
| mikewarot wrote:
| Getting some hands on experience with the signal processing
| side of SDR, with GNU Radio can help with understanding things
| like negative frequencies, complex signals, etc.
|
| It's open source, and you can just play with your audio ports
| for starters. Later adding a $40 rtlSDR kit goes a long way. I
| used mine to build a VOR receiver.
| rtrunck wrote:
| As a pilot with an amateur radio license (though an
| inexperienced ham) this sounds really interesting. Could you
| elaborate more on building the VOR receiver?
| mikewarot wrote:
| The transmitter has an electronically switched antenna that
| virtually moves in a circle at 3600 rpm, causing FM
| modulation phased with direction. The carrier is also AM
| modulated with a reference phase signal.
|
| I built a gnu radio flowgraph to receive both and display
| heading to the VOR.
| NoboruWataya wrote:
| Aaaand now I've gone and dropped PS35 on an SDR dongle.
| topspin wrote:
| The next waypoint on your journey is SDRplay.
| jquinby wrote:
| I use an RSPdx in my shack and it's one of my all time
| favorite pieces of hardware.
| th0ma5 wrote:
| GQRX is great
| lysace wrote:
| Now you can use one of your unused Raspberry Pi:s (we have all
| got them) to cobble together an ADSB unit that may be critical
| in recording important low-height ADSB flight data points in
| your immediate area in case of accidents.
|
| And also get free premium accounts on sites like flightradar24
| etc.
|
| https://hub.balena.io/apps/1829313/balena-ads-b
| rylittle wrote:
| I inherited a HackRF One from a friend and this thread reminded
| me about it. Does anyone have any cool projects they recommend
| doing just to gain some experience in SDR / have fun?
| __turbobrew__ wrote:
| I found following these videos through was a good intro:
| https://m.youtube.com/watch?v=BeeSN14JUYU&pp=ygUII2hhY2tyZmY...
|
| There were a few things in GNU radio which have changed since
| then (different block names) but with a bit of googling you can
| figure out how to work around it.
|
| Unfortunately for me, SDR is too much like $dayjob so I lost
| interest. I already spend 8 hours a day at a computer I cannot
| be convinced to spend more time at a computer doing SDR as I
| would much rather being doing stuff outside.
| drivers99 wrote:
| Do SDR stuff outside! Seriously though, I know for ham radio
| stuff at least, a lot of it can be outside if you want.
| dummydummy1234 wrote:
| Write a FM receiver/transmitter from scratch.
|
| It's very straight forward, depending on your desired level of
| difficulty: Do it first using blocks in gnuradio, then redo it
| with blocks you write yourself.
|
| After that do the same thing, but with digital psk modulation,
| it has the added difficulty of requiring channel estimation/
| equalization.
| ww520 wrote:
| Has anyone work on decoding over-the-air TV digital signal in
| software? I remember way back there were some cards that can
| decode OTA signals to be recorded into DVR.
| bri3d wrote:
| The RTL-SDR was originally intended as a DVB-T receiver, using
| an app called "BlazeVideo."
|
| Anyway, many, many open source implementations exist for this
| as it's a popular first/early SDR project. All you'll you need
| is the right keywords - for the US, ATSC, and for Europe,
| DVB-T2.
| pests wrote:
| Yep.
|
| I just dug my RTL SDR v4 out of the drawer right before a
| trip to Florida. Guess this is a sign to get it going.
| th0ma5 wrote:
| With something with more bandwidth than an RTL-SDR you may be
| able to at least capture the data but having dedicated hardware
| for the target signal is the easiest if you're looking to tune.
| I've seen POC Analog TV signal decoding but not digital signals
| in software beyond some exploration and general signal
| analysis.
| drmpeg wrote:
| GNU Radio comes with receivers for ATSC and DVB-T. You'll need
| an SDR that can provide 6 MHz (ATSC) or 8 MHz (DVB-T) of
| bandwidth (which an RTL-SDR cannot do).
|
| DVB-T2 and ATSC 3.0 receivers are too difficult and nothing
| exists for them.
|
| Here's a screenshot where I'm transmitting to myself (GNU Radio
| also has an ATSC transmitter).
|
| https://www.w6rz.net/atscdemo.png
| anamexis wrote:
| > (which an RTL-SDR cannot do)
|
| Is that true? RTL-SDR are derived from a chip designed for
| DVB-T tuners.
| drmpeg wrote:
| Maximum sample rate is 3.2 MS/s.
|
| https://www.rtl-sdr.com/about-rtl-sdr/
| asdefghyk wrote:
| If always wonder if their was a 4g to 3g converter to keep old
| devices working when 3g network shut down.
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(page generated 2025-03-10 23:00 UTC)