Search found 23 matches

by jpsa
Fri May 26, 2017 9:31 am
Forum: Code Corner
Topic: Raspberry Pi problem?
Replies: 18
Views: 3681

Re: Raspberry Pi problem?

I don't know: I eventually found a formula which worked reliably enough. Rather than using one of the non-zero-IF modes, I use zero-IF with 4xdecimation and tune so the signal I want is off centre to avoid the DC spike. That didn't completely eliminate the problem, but it did then take several days ...
by jpsa
Fri Mar 17, 2017 8:31 am
Forum: General
Topic: Interference identification?
Replies: 37
Views: 7519

Re: Interference identification?

Well this thread must be jinxed...I enjoyed mostly unharmed reception until this weekend but now... :( ...exact 1 second pulses from 0 to 10 MHz and some dense muck between 2 and 3 MHz... I see stuff a bit like that too, periodic in both time & frequency, affecting mostly 3 MHz - 5 MHz or there...
by jpsa
Sat Mar 11, 2017 2:19 pm
Forum: General
Topic: Interference identification?
Replies: 37
Views: 7519

Re: Interference identification?

Oh, thank you. That makes sense: we've had a new neighbour move in recently. Looks as if I'll just have to put up with it. :(
by jpsa
Sat Mar 11, 2017 10:36 am
Forum: General
Topic: Interference identification?
Replies: 37
Views: 7519

Interference identification?

Approximately every 15 seconds, I get 3 (occasionally 1 or 2) short bursts of interference over most of the range 10 MHz - 30 MHz. (qrm1.jpg & qrm2 jpg). Looked at in more detail, the interference seems to have some kind of sub-carrier structure with a spacing of about 780 Hz (qrm3.jpg). There a...
by jpsa
Fri Feb 24, 2017 11:54 am
Forum: Code Corner
Topic: Raspberry Pi problem?
Replies: 18
Views: 3681

Re: Raspberry Pi problem?

More experiments... My RSP2 seems to work just fine with the test program on the RPi3. I ran it for 32 hours without seeing a single problem. Reverting to the RSP1 (but keeping everything else -- RPi, USB cable, Antenna, test executable -- identical), the problem is still there: after running for a ...
by jpsa
Tue Feb 21, 2017 5:39 pm
Forum: Code Corner
Topic: Raspberry Pi problem?
Replies: 18
Views: 3681

Re: Raspberry Pi problem?

I'll try -O3 too... Progress report: the problem still occurs with no USB stick in use (or plugged in), and with the RSP1 connected to a different USB port. I'm currently testing with a different USB cable. Other things I can try are using a different physical RPi3, and using an RSP2 instead (I've g...
by jpsa
Tue Feb 21, 2017 2:15 pm
Forum: Code Corner
Topic: Raspberry Pi problem?
Replies: 18
Views: 3681

Re: Raspberry Pi problem?

How long is a while? Your simple test code has been running on my RPi3 for about 10 minutes without a problem. Anywhere from a few minutes to several hours. The longest I've had to wait was about 10 hours, the average is probably about 3 hours. Sometimes I think it takes longer to go wrong if there...
by jpsa
Tue Feb 21, 2017 10:16 am
Forum: Code Corner
Topic: Raspberry Pi problem?
Replies: 18
Views: 3681

Re: Raspberry Pi problem?

I don't think maxing out the processor should be the problem, because the stream callback is doing very little in the cut-down example provided above: just calculating I*I+Q*Q for each sample. The processor is only running at about 35% according to 'top' (I believe this number to be relative to a si...
by jpsa
Sun Feb 19, 2017 9:53 am
Forum: Code Corner
Topic: Raspberry Pi problem?
Replies: 18
Views: 3681

Re: Raspberry Pi problem?

OK, I've done some more experiments, all with an RSP1 and API version 2.09 running on a Raspberry Pi 3. With an fs of any of 2.000, 2.400, 3.000; a decimation factor of 4; and an intermediate frequency of zero, the problem does not occur. I ran it for 24 hours each, which should have been plenty of ...
by jpsa
Tue Feb 14, 2017 1:56 pm
Forum: Code Corner
Topic: Raspberry Pi problem?
Replies: 18
Views: 3681

Re: Raspberry Pi problem?

Can you try using a fs > 2.685MHz to see if that artifact goes away? Franco I'll try that... note, though, that I'm currently using a 450 kHz IF (see mir_sdr_StreamInit parameters listed in my original post, above), and this change will force me to switch to using an IF of zero, so presumably will ...

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