qs1r-multirelay source code
Posted by Guenael in Radio & Wifi, tags: multi-channel, QRSS, QS1R, receiver, SDRAs promised, I released the source code of my program. Nothing exceptional, just some lines of code to dispatch the multiplexed IQ output of the receiver into 7 audio channels. For this, I used the qs1r framework from Phil (N8VB) and the Verilog part written by Alex (VE3NEA).
My prog needs few more features and bugs correction, but I already corrected a major bug about a buffer leak. The QS1R buffer and the audio buffer are not perfectly synchronised and moreover, the Window (MME) audio buffers jams sometimes and skips some data. Instead to try to compensate this with an adaptive buffer (which grow rapidly), I simply drop some frames :)
The source code & binary (version 0.1 alpha) can be downloaded here, or on my Github : http://github.com/Guenael
The audio relay could be modified to work directly with CwSkimmer. It’s not interesting for the Linux users, but the community that uses CwSkimmer to contribute to ReverseBeaconNetwork could spot CW QSO as usual, and in the same time, take some QRSS captures. The CWSL projet (OL5Q) allows to duplicate the data flow to another application (ex: HDSDR, an audio file recorder) and my qs1r-multirelay could be rewritten to read the shared memory. The RBN community is larger than the QRSS community and some hams could be interested to participate and share their receiver. Unfortunately, I have no feedback about multi-channels grabbers on the KnightsQrss mailing list and I won’t spend more time on this project. The source code is available, anyone can play with :)
qs1r receiver board
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Hi Guenael,
To get 7 “virtual” receivers on the QS1R, I guess you have 7 BPF (one for each antenna/band) in front of the QS1R input, right ? Can you elaborate, please ?
Laurent – F6FVY
No need of extra BPF, qs1r is a direct sampling receiver @ 125Msamples/sec. The maximum frequency is f nyquist / 2, but the LPF in place is around 55MHz. The huge amount of data is mixed and decimated in the FPGA to get the 7 streams. Check these websites for more details :
http://www.srl-llc.com/
http://qs1r.wikispaces.com/
http://www.dxatlas.com/SkimServer/
73
Tnx for the reply, but I think extra BPFs would be required when using several dedicated antennas for given freq. ranges (monobanders for example). Of course, if you’re using a single (wide range or multi-band) antenna, BPF are useless. Look forward to see your progress on ur SDR system project.
73
Laurent – F6FVY