ESP-SDR is based on this work, and supports the C5 and a bunch more
"oh, no problem"
>tippy tappy
>brrrrrrr
The MT7996 chip is available with the banana pi R4 board, which has SFP+ (10 gigabit) so you'd have a near completely open ISM band SDR platform right there, feeding data to your server via fiber optics.
According to this TX is also possible on the ESP32-series chips, though they haven't published exactly how (I assume due they don't want to wake the FCC). But yeah the ESP32 is fairly limited in a lot of ways due to the limited processing power and IO bandwidth to stream data out of it
Like Wi-Fi chips, they don't use SDR mode during most of the normal operation. They have dedicated hardware units that do a lot of the decimation, conversion, modulation and demodulation efficiently. But the "SDR mode" is still there for things like factory calibration.
Makes me wonder how many other common MCUs and SoCs are just waiting for someone to unlock SDR in them.
TX is less "not possible" and more "this dev doesn't want to enable it" from what I gathered. Probably for "I don't want people using this to shit all over the spectrum" kinds of reasons. So you can get TX - it'll just require extra hacking.
Those hardware blocks could be useful for certain applications but most importantly for triggering captures only when there are frames to process and giving you both the frame + the sample.
So for me the perfect hack would allow both normal Wi-Fi tx/rx and triggered or continuous rx sampling.
Base stations are also SDRs by the way xD
Is the "QLink" setup they use in 5G systems now just a thin protocol running over LVDS and streaming I/Q between the transceiver and SoC DSP as digital signals?
Never actually went that far, but I did wonder if you could plug a QLink tuner chip into an FPGA to use it as a broadband SDR frontend.
The motivation for this is of course beamforming, angle of arrival, spatial streaming, etc. You connect multiple antennas with different views back to the base station.
Receive only SDRs have been cheap for a long time now.
HackRF is not as good at listening -- a bit deaf -- but does provide much larger bandwidth and obviously the low powered half duplex tx ability.
If you just want to grab random signals around and explore, get a cheap RTL.
If you really want to go back and fourth with a device, to modify data packets etc get a hackRF.
If you want to push beyond those limitations, you'll probably already know what you're shopping for next at that point.
Beware, you'll end up acquiring many different radio devices and then likely start building antennas out of scrap, buying a nanovna, and falling deeper and deeper into the magical rabbit hole!
Last time I was down this rabbit hole (when cheap RTL-SDRs were completely new), my favorite fun test was ADS-B, so let's say I wanna play around 1-1.1 GHz at first.
One day I also wanna sit down and do GPS from scratch, "by hand", so let's say I also wanna do 1.57 GHz (which I understand is becoming borderline difficult for the cheapest devices?).
Even though these devices are cheap, I'd rather avoid needlessly extra-shitty devices or my money going to copycat leeches.
Any recommendations in light of these requirements? Thanks a lot!
> HackRF is not as good at listening -- a bit deaf -- but does provide much larger bandwidth and obviously the low powered half duplex tx ability.
Yeah I know it's in a completely separate category, I just derail and start daydreaming ;-)
> Beware, you'll end up acquiring many different radio devices and then likely start building antennas out of scrap, buying a nanovna, and falling deeper and deeper into the magical rabbit hole!
Lol! I can see that danger very clearly!
This is "from scratch": https://lea.hamradio.si/~s53mv/navsats/theory.html
:)
Very, very cool link!
- You need stable clock for the processing algorithms to be happy, RTL-SDR blog dongle have 0.5ppm TCXO while who knows what crystal they use on the no-name ones
- RTL-SDR blog dongles have bias-T, and a lot of GPS patch antennas are active antenna that need power from the coax to power the LNA
[1] https://www.hfsignals.com/index.php/sbitx-v3/
[2] Recent discussion: https://news.ycombinator.com/item?id=49789228
I guess the problem with these is they are more likely to be tied/tuned for specific (wifi) frequency ranges. Although 2.4GHz gives bluetooth and zigbee in addition to wifi
This development makes me hope that we'd be seeing more of these on common Wi-Fi cards, so that every random laptop could be used as an SDR for many fun and useful applications on a budget.
https://github.com/h0m3us3r/eSpDR