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WebSDR – Internet-connected Software-Defined Radios

websdr.org

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Re: WebSDR – Internet-connected Software-Defined Radios

#61

Post by rlex »

imroot wrote: post #14
rlex wrote: post #10

Earlier quoted context omitted.

for open source alternative take a look at https://www.openwebrx.de/ Can also demodulate digital modes (DMR, YSF, etC) and it have nice, modern UI. WebSDR have a weird list of requirements if you want to get install file - should open instance to public, provide lots of info, etc etc etc. It's not just closed-source.

I thought that it couldn't demodulate DMR and other modes unless it had the hardware to do so. Feel free to correct me if I'm wrong, though.

You definitely can, but legality of such procedure is questionable. DMR uses AMBE codec, which require licensing from DVSI, but you can find open-source implementation on github (mdelib, jMBE). Projects such as DSD-FME[1], which allows you to decode much more than just DMR (P25, NXDN or SDRTrunk[2], which allows you to listen to trunking systems (p25, dmr tier 3 and much more) uses software implementation. OpenWebRX users software decoder too https://github.com/jketterl/digiham

[1] https://github.com/lwvmobile/dsd-fme

[2] https://github.com/DSheirer/sdrtrunk

Re: WebSDR – Internet-connected Software-Defined Radios

#63

Post by CrankyCanuck »

nolroz wrote: post #62

Why are there none in Canada? Or Australia? Are there parts of the world where Internet connected SDR is illegal or something?

There are some (SDRs on the internet) Have look here. https://rx-tx.info/map-sdr-points

http://ve3hoa.ddns.net:8073/

Re: WebSDR – Internet-connected Software-Defined Radios

#64

Post by kareiva »

lormayna wrote: post #46

Is there any good open source software for WebSDR? I am living in a very noisy area from RF standpoint, but my parents are living in a better position. So I was thinking to install a SDR and a Raspberry and use them as remote SDR

OpenWebRX is a good thing to start with, especially the fork at https://github.com/luarvique/openwebrx/

Re: WebSDR – Internet-connected Software-Defined Radios

#66

Post by luke-stanley »

Oh cool. I suppose since they have locations too, it should be possible to profile aggregated mains power fingerprints from these for video time and location fingerprints. Though that said, there are probably a few ways to collect that info. If you know the frequencies to profile you could probably store the mains hum for all of them and have a good go at geo-locating video and audio content for many places.

Re: WebSDR – Internet-connected Software-Defined Radios

#67

Post by westurner »

superkuh wrote: post #40
westurner wrote: post #32

Earlier quoted context omitted.

From the WebSDR FAQ: > Q: My SDR can be tuned from 0 to 30 MHz (or from 25 to 1900 MHz, or whatever). Can I offer all of that tuning range to the users? > A: No. Such an SDR does not feed the entire 0-30 or 25-1900 MHz spectrum to your computer: that would be way too much data. Instead, a small part (at most a few MHz) are filtered out in external hardware, centered around some frequency that you can tune. With the W…

>Rydberg antenna range: 0-20Ghz, https://news.ycombinator.com/item?id=28402527 https://en.wikipedia.org/wiki/Rydberg_atom Actually the instantaneous bandwidth of a ryberg antenna based receiver is only about ~4 MHz in implementation papers I've read. A good fit for a 2 MHz instantaneous banwidth $20 rtl-sdr dongle. The 0-20 GHz is the tuning range (again).

How many 4 or 2 Mhz antenna/transceivers are necessary to sufficiently cover a 0 to 1 Ghz (0 to 1000 to 1000000 Mhz) band? What about to cover 1 Thz: (terahertz) band(s)?

How should they be placed in spacetime to minimize signal loss e.g due to crosstalk and cost?

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