Search found 13 matches

by dlonard
Mon May 30, 2016 3:45 pm
Forum: Project showcase
Topic: BladeRF astronomical interferometer
Replies: 15
Views: 39082

Re: BladeRF astronomical interferometer

Jon, I've been able to get synchronized reception from my three BladeRFs with the latest FX3 firmware, FPGA images and bladeRF-cli, following the write-ups on how to get this going. The FIFO approach that you suggested works well, with the caveat that the temp files for each BladeRF grow very large,...
by dlonard
Thu May 26, 2016 6:06 am
Forum: Project showcase
Topic: BladeRF astronomical interferometer
Replies: 15
Views: 39082

Re: BladeRF astronomical interferometer

Jon,

Thanks, the FIFO approach looks like it might be the way to go. Should have some results soon.

David
by dlonard
Tue May 24, 2016 6:04 am
Forum: Project showcase
Topic: BladeRF astronomical interferometer
Replies: 15
Views: 39082

Re: BladeRF astronomical interferometer

Jon, I'm excited to try it out and thanks for the example. I've got three radios that need to be synchronized and I think I should be able to figure it out. Ultimately, I would like to be able to execute the triggering from within a GnuRadio flowgraph. I will keep everyone posted on my implementatio...
by dlonard
Wed Jan 27, 2016 9:45 am
Forum: Project showcase
Topic: BladeRF astronomical interferometer
Replies: 15
Views: 39082

Re: BladeRF astronomical interferometer

I've done some more work to get three BladeRFs to cross correlate data in 'real time' now for those who are interested. A grc flowgraph and a Python script communicate over a TCP socket now, so data doesn't need to be stacked up on big solid state drives and post-processed. See the link below. Once ...
by dlonard
Sun Dec 27, 2015 9:11 pm
Forum: Project showcase
Topic: BladeRF astronomical interferometer
Replies: 15
Views: 39082

Re: BladeRF astronomical interferometer

Thanks for the clarification, yes I am more interested in the ability to synchronize devices, preferably on a 1 PPS pulse from a GPSDO. I assume that a master radio could send a pulse to slave radios as an alternative, then no extra hardware would be needed. I think it would be straightforward to ch...
by dlonard
Sun Dec 27, 2015 2:54 pm
Forum: Project showcase
Topic: BladeRF astronomical interferometer
Replies: 15
Views: 39082

Re: BladeRF astronomical interferometer

Jon, Thanks, I look forward to the 10 MHz/1 PPS synch functions going mainline. I'm still a ways off from being able to correlate signals in real-time, so I am content to process everything after recording right now. Without 1PPS synching, individual BladeRFs are about ~5000 to 10000 IQ sample pairs...
by dlonard
Sat Dec 26, 2015 10:47 am
Forum: Project showcase
Topic: BladeRF astronomical interferometer
Replies: 15
Views: 39082

BladeRF astronomical interferometer

Hello Everyone, I thought I would post some of my work on using three BladeRFs as SDR interferometers for radio astronomy. If you follow the links provided below, you can see some of the data from work that I've done at 60 MHz and 140 MHz. I haven't tried out the various approaches that are emerging...
by dlonard
Sat Dec 07, 2013 7:46 am
Forum: Troubleshooting
Topic: subtle noise issue inside of BladeRF
Replies: 6
Views: 14616

Re: subtle noise issue inside of BladeRF

I found out what my problem was with the noise problem. In my Gnuradio companion flowgraph Osmocom source block following an example I had seen in the forum, I had "Ch0 DC Offset Mode" and "Ch0 IQ Balance Mode" set to "automatic". When set to "off", everything is o.k., my IQ balance issue is also fi...
by dlonard
Mon Nov 25, 2013 5:24 pm
Forum: Troubleshooting
Topic: subtle noise issue inside of BladeRF
Replies: 6
Views: 14616

Re: subtle noise issue inside of BladeRF

I'm using this Python script to process IQ data files that were generated from the BladeRF and Gnuradio (16 bit intervealved IQ binary files). It is doing a lot of averaging on 400 Gb data files saved using a SSD to capture data arriving at 30 MSPS, but it could work on files captured at any sample ...
by dlonard
Sun Nov 24, 2013 6:32 pm
Forum: Troubleshooting
Topic: subtle noise issue inside of BladeRF
Replies: 6
Views: 14616

Re: subtle noise issue inside of BladeRF

I included a cap and inductor to filter the 5V source that is channeled into the USB3 cable while still within the computer, but perhaps that is not enough to clean it up sufficiently or it is picking up RF from the data wires. I'll try out a separate 5V supply.