HN user
GNU Radio Project officer, Electronics, Open Source, Vegan, and a dash of black magic. PhD Researcher at Cardiff University.
Low cost radio telescopes are great fun.
A few other similar projects:
Https://arise.seti.org/
https://wvurail.org/dspira- lessons/
https://www.haystack.mit.edu/haystack-public-outreach/srt-th...
Came with the same thought!
Thanks Fabien!
Also I love all your retro work. I have a NeXTStation Turbo Color that's my retro pride and joy. Have you seen or been involved in any of the Demoscene activities? It's amazing the graphics that people are able to squeeze and abuse out of older hardware.
Off topic, but folks might enjoy Poems for Bugs, a talk where Linus Åkesson talks about cycle accurate coding to exploit GPU bugs in the C64. https://www.linusakesson.net/programming/poems-for-bugs/inde...
No segway, I've posted a bit of a discussion above. Not all that interesting unfortunately. The error message was obscure but the problem space was pretty small so I did mostly the same thing as Fabian and searched online for related terms to PCIe hotplugging and PCIe address allocation.
Hi folks. :)
I'm so glad that my hit-and-run post has been so useful. After seeing Fabien's blog post I did a quick search and it turns out that the solution has spread fairly broadly to other forums. My choice of 0x33 was arbitrary so makes a nice canary for seeing it spread out. I'm thrilled. Sharing experiences and solutions is so essential to learning. I've benefited enormously from the generosity of open source developers and communities and from individuals documenting pieces of their projects, glad to have raised the ocean a little in return.
My use case was (and remains) having a Xilinx Artix 7 FPGA in an external Thunderbolt 3 enclosure for testing the development of DSP accelerators using open source tooling. I didn't want to have the FPGA board inside the PC to be able to swap it to my laptop easily, because it produces a lot of heat, and so when I misused the PCIe soft core (litePCIe: https://github.com/enjoy-digital/litepcie/) it doesn't take down the OS. Being able to reload the FPGA and effectively hotplug the device has been very helpful.
Since I knew my issue was around hotplugging I searched for information around PCIe hotplugging and I think (it was two years ago...) that I found the answer from one of these two threads. Both mention the option of reserving PCIe addresses for hotplug busses as a workaround, and a workaround was all I needed.
https://www.spinics.net/lists/linux-pci/msg64841.html
https://review.coreboot.org/c/coreboot/+/35946
dmesg and the various kernel logs are my first stop for any odd behavior on Linux. Especially with any state change to a device (plugging in, turning on, removing, reconfiguring etc) the kernel logs tend to give invaluable info.
I had already been looking at eGPU forums to choose the Thunderbolt 3 enclosure (ended up with the ORI-SCM2T3-G40-GY) and there were various discussions of hotplugging issues there, but I don't think I found the specific kernel options to fix it there.
Check out this docs page for the kernel parameters: https://docs.kernel.org/admin-guide/kernel-parameters.html
For the string "pci=realloc,assign-busses,hpbussize=0x33"
`realloc` Enable/disable reallocating PCI bridge resources if allocations done by BIOS are too small to accommodate resources required by all child devices.
assign-busses [X86] Always assign all PCI bus numbers ourselves, overriding whatever the firmware may have done.
`hpbussize=nn` The minimum amount of additional bus numbers reserved for buses below a hotplug bridge. Default is 1.
0x33 (decimal 51) is arbitrary, but large enough that I was unlikely to ever exhaust that address range even with a large number of devices chained together on the Thunderbolt bus. I think (though would have to check) that the address space does get exhausted with multiple hotplug cycles. I haven't hit that issue since I shutdown the computer close to daily to save power.
Sadly, there's no Segway, those things are expensive and I have a long wish list before reaching that point. Currently I'm saving up to get a microscope, I have a large box of RF integrated circuits that I'd like to do some show and tell with on Twitch. :) Also no unmarked 40% keyboard, RSI means I'm a total fanboy of the Microsoft Ergonomic keyboard and the Anker vertical mouse. Cheap and so comfortable. I have done some kernel compiling, mostly to learn more about kernel modules as I've been trying to make the learning curve and user experience of experimenting with FPGAs over PCIe easier. If anyone has some experience with DKMS and creating Debs I'd welcome a chance to chat. Ditto if there's any Debian maintainer with experience packaging kernel modules, I made some headway a while back to repackage linux-gpib but got stalled out on a few of the details of maintaining patches against the upstream.
Cheers and Happy Holidays!
Now 2022. ;)
What solution did you find?
Yes, there's many people who would be interested in another explanation of quadrature sampling and why it is essential in modern communications DSP.
A few that I think are useful or have interesting components are:
* https://pysdr.org/content/sampling.html#quadrature-sampling
* https://visual-dsp.switchb.org/
* Understanding Digital Signal Processing by Richard Lyons
This has been the most exciting software work I've seen in the last year. David is doing fantastic work. If you haven't seen anything about the development of these tools his talk at FOSDEM in February was quite good.
https://archive.fosdem.org/2019/schedule/event/trellis_and_n...
Hi, I'm one of the GNU Radio project officers (general busybody).
GNU Radio is used extensively in industry and academia. Hawkeye 360 and Spire use GNU Radio for satellite ground stations. Lockheed Martin, SpaceX, and a variety of other aerospace/defense use it as well for other wireless comms applications. DeepSig uses GNU Radio at least to generate test signals for their neural net based signal classification system and communication systems, possibly also internally. Analog Devices uses GNU Radio in their Scopy oscilloscope/spectrum analyzer/signal and logic analyzer application.
As said by the other commenter, check out the videos on our YouTube channel. The project is very fortunate to attract many interesting talks and speakers each year at the conference.
https://www.youtube.com/GNURadioProject https://www.gnuradio.org
The Open Source Radio Telescope project hasn't setup any phased array setups yet, but the Canadian Centre for Experimental Radio Astronomy uses GNU Radio for it's phased array receivers looking at pulsars. http://www.ccera.ca
I follow a nearly identical flow several times a day to connect bluetooth headphones to my laptop.
- Turn on headphones * Laptop connects immediately and uses the HSP/HFP mode (works!) * Trying to select A2DP appears to work, but no audio will play - Disconnect the headphones using the Bluetooth manager - Reconnect the headphones using the Bluetooth manager - Select A2DP, this now works.
https://bugs.launchpad.net/ubuntu/+source/bluez/+bug/1438510
Separately, many web videos will stop playing and refuse to play when the Bluetooth audio device is selected.
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1589008
You can do a very simple, though somewhat permanent, modification to the dongle and receive DC-14MHz. http://www.rtl-sdr.com/rtl-sdr-direct-sampling-mode/
Microwaves & RF : http://mwrf.com/
Electronic Design : http://electronicdesign.com/
IEEE Spectrum : http://spectrum.ieee.org/
Lobsters (HN with less noise) : http://lobste.rs/
Does anyone have recommendations for good electrical engineering/communications newsletters/sites?
AG6PO here. I became licenced during my second year at university. It has actually been one of the most important parts of my professional path to this point.
If you haven't yet, buy a basic hand held radio and get transmitting. The Baofengs are actually tolerably good radios and super cheap. Getting on the air is the best way of participating in the community and growing in the hobby/skill.
Then yes, absolutely start homebrewing. I find antennas to be easy and and fun to experiment with. The Rigol's 100 MHz limit won't actually be much of a problem for you. It is plenty enough to analyze all the baseband signals and also the intermediate frequencies used in many radio designs.
I'll send you one this afternoon. I'd love to have this happen.
Anyone else interested can email me at derek.kozel at gmail.com
http://lobste.rs is very similar to HN and open source under a BSD licence. I'd be very interested in an embedded/electronics themed site and would be willing to help/lead with the creation of it if there was enough interest.