rtlsdrblog wrote: ↑
Sat May 11, 2019 12:23 pm
The main intended use of the KSDR is for coherent experiments, so the part about Linux only was probably referencing the fact that the coherent software we've made for the KSDR is Linux only.
Thanks for clarifying that, and; although I've got the unit to work now in both my Win7/64bit and on my Raspbian Stretch Linux running on RPi3B+, I'm still experiencing a few issues.
First of all, it seems that there's a clutter in the USB lane somewhere whenever I'm using the KSDR as multiple RTL-SDR's, even if it's just two of them. Whereas with my Win7/64bit desktop PC I can easily use 2x RTL-SDR.com's USB dongles in a simultaneous real-time dual setup without any audio playback problems while running SDR-Console v3, and doing so with higher sample rates/bandwidths than on the KSDR.
However, trying to achieve a similar setup to the 2xRTL-SDR USB dongles with just the KerberosSDR - even with low resolutions and over a USB3 connection - is not working properly. On a KDSR setup equivalent to the two-dongle RTL-SDR setup, and with two of the receivers switched OFF using the DIP switches, the audio is constantly being cut on and off in a fast pace.
It sounds like an audio buffer/processor underrun to me, although there seems to be no problems related to CPU/GPU/RAM etc usage. The frequency of the audio cut-outs [as in; their tempo], a.k.a. "audio ouput glitch tremolo" seems to be related to the selected sampling bandwidth of each of the units. However, tweaking any of the SDRCv3's settings doesn't really help.
So, as for now, I can only get the KSDR to run without any audio cutouts on the Win7/64bit PC by using only one single RTL-SDR out of its four built-in tuners. If I enable just two of them simultaneously (using two SDRConsole v3 instances), the troubles start immediately. I'm unsure exactly where the problem is -- in limitations to hardware capabilities (either in the KSDR or in my PC), a driver problem, a limitation in USB3.x lane's packet handling or what. With 2x RTL-SDR dongles, the same kind of setup worked just fine, and there was still plenty of CPU+GPU+RAM to play with.
I have not yet managed to calibrate the device on my RPi3B+ Linux box, I'm wondering if that could be a factor [does the KSDR sync calibration save some settings into the KSDR? Since there are no documentations/schematics/flowcharts etc on its inner workings, it's a bit hard for me to tell].
As for the Linux box on my RPi3B+, I got the KSDR working using a single tuner with various available SDR software, but I'm still having some issues when I'm trying to run KerberosSDR's audio noise source calibration. Will have to keep looking into both of those issues.
If anybody has some ideas on what could be the cause for the audio problems (very similar to these, btw: viewtopic.php?t=592
), please let me know. All help highly appreciated.
Thanks a lot.