argilo

5 ms·

1.
by argilo 2y ago
An SDR's sample rate only limits its bandwidth. Most devices include a mixer, which allows the transmitted or received signal to be shifted in frequency by an amount much larger than the bandwidth.
2.
by argilo 2y ago
It's definitely possible to transmit multiple TV channels at once, and I have experimented with that in the past. Since TV channels are 6 to 8 MHz wide (depending on what part of the world you're in) there are practical limits to
3.
by argilo 3y ago
The cars on the map are the locations of people who are hunting for balloons after they have fallen back to earth. SondeHub's "chase mode" allows you to announce your position so that others will know you're in the area
4.
by argilo 3y ago
The code of nrsc5 (and my transmitter project, https://github.com/argilo/gr-nrsc5 ) would be the best source of information for the undocumented parts. I do have some private notes, but the useful information has alread
5.
by argilo 3y ago
There's an issue open for this: https://github.com/gqrx-sdr/gqrx/issues/1104 I could really use some help from a software build expert. Gqrx and all its dependencies would need to be built in CI with App
6.
by argilo 3y ago
I am also the maintainer of Gqrx and I would love for it to have a built-in NRSC-5 receiver. The trouble is that some aspects of NRSC-5 are still patent-encumbered, which makes software distribution problematic. For that reason, nrsc5 is on
7.
by argilo 3y ago
Most of the details are available in the specification, which is available here: https://www.nrscstandards.org/standards-and-guidelines/docum... The missing parts are the audio codec (HDC) and the formats of the variou
8.
by argilo 3y ago
Also, all of those stream types seem to be used across multiple stations. I haven't seen any weird one-off streams.
9.
by argilo 3y ago
That decision was made by the original author (Andrew Wesie), but I think it makes sense because nrsc5 only needs a tiny fraction of the functionality that GNU Radio provides. Implementing the functionality directly in nrsc5 avoids the need
10.
by argilo 3y ago
It would only be possible if the tuner exposed raw RF samples, the way RTL-SDR dongles do. I'm not sure whether any of the integrated FM receivers do that.
11.
by argilo 3y ago
I'm not aware of any digital-only FM stations either. But there are a handful of digital-only AM stations, like WWFD.
12.
by argilo 3y ago
Some stations have "HD TMC" (traffic message channel) streams. The others that I've encountered are "HERE Images" (traffic & weather radar images, discussed and mostly reverse engineered in https://gi
13.
by argilo 3y ago
Also, I should mention that Python is not a requirement. The GUIs that people have created so far were written in Python, but the nrsc5 project itself is built entirely in C, and it exposes a C API.
14.
by argilo 3y ago
The documents look to be available here: https://www.drm.org/specification/
15.
by argilo 3y ago
Models targeting the SDR market (e.g. from RTL-SDR Blog or NooElec) do have some improvements compared to models sold as TV tuners. Most importantly, they often include a more accurate crystal oscillator, which is useful when receiving narr
16.
by argilo 3y ago
I haven't investigated the CPU and RAM requirements in depth, but I have used nrsc5 on a Pi 3B without issue. I suspect a Pi Pico would be too small.
17.
by argilo 3y ago
RTL-SDR tuners usually have very good reception between 50 and 1000 MHz, which includes the FM broadcast band. It is easy to overload the analog-to-digital converter, so it's important to make sure the gain is not set too high. Setting
18.
by argilo 3y ago
Yes, it is similar. It is used primarily in North America, while DAB is used primarily in Europe.
19.
by argilo 3y ago
It might be possible, but I'm not sure whether a typical router would have enough CPU horsepower to do the processing required to demodulate the signal.
20.
by argilo 3y ago
Time information is broadcast, but in my experience it's often inaccurate. There's also a special stream for emergency alerts, but I haven't seen it in use. There are various data streams, but not DVB. A lot of the details ar
21.
by argilo 3y ago
In addition to files, some stations also send out "stream" and "packet" data. There is ongoing work to reverse engineer the formats. See the discussion here for details: https://github.com/theori-io/
22.
by argilo 3y ago
Some stations send out traffic and weather images (as well as album art and station logos). The files can be dumped to disk using nrsc5's "--dump-aas-files" option. A few people have built GUIs that display the information in
23.
by argilo 3y ago
My preferred dongle is the RTL-SDR Blog V3: https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/ They also have a new V4 version, but it requires updated drivers that will take a bit of time to percolate out to Linux dis
24.
by argilo 3y ago
I've heard that term as well, but the official site denies it: https://hdradio.com/trademark/
25.
by argilo 3y ago
DRM broadcasts are definitely hard to find. A schedule is available here: https://www.drm.org/what-can-i-hear/broadcast-schedule-2/
26.
by argilo 3y ago
I'm happy to hear you found it useful!
27.
by argilo 3y ago
If you live within the coverage area of an FM radio station that's sending weather radar, it will probably be easier to receive than NOAA satellites.
28.
by argilo 3y ago
I'm a co-maintainer of this project. If anyone has questions, I'd be happy to answer them.