I’ve been playing around with a LimeSDR (firmware/gateware v1.4) for about two weeks now and I’m having trouble transmitting with the LimeSDR device in GNURadio. Here’s the waterfall of the receiver and the transmitter:
Real-time duration of the waterfall is 10 seconds. You can see the transmitter has transmitted about 8 seconds of signal and the dropouts are visible in the received signal. Here is the flowgraph I am using:
I’ve tried several iterations to try and tease out the culprit, unsuccessfully to date:
- Use a 2.6MHz bandwidth with 8 bit samples and rational resampler (minimum file read/write)
- Use a 10MHz bandwidth with 16 bit samples (minimum computational requirement)
- Disable the receive chain (in case the receiver was interrupting the transmitter)
- Use two different computers (i7 duo and 8 core Xeon) both using USB3.0
- Use two different environments (GNURadio on Ubuntu 16.04, GNURadio via Pothos on Windows 7)
I have the same issues every time. I am using the latest master branch for LimeSDR and I’ve used GNURadio from the myraidrf PPA and master via PyBOMBS. Within the bursts of data transmission I can confirm my signal (simulated GPS) is coming through. I just need the dropouts to go away.
Looking for help/advise - thanks,
philip hahn
sdrgps.blogspot.com