I always thought these pulsations were due to some kind of bug with
Gqrx. If you change the FFT size, the rate of pulsation changes. Also,
you don't see this on a real spectrum analyzer, even an inexpensive one.
Ron
On 12/21/19 09:25, Marcus Müller via USRP-users wrote:
Just to rule out interferers:
* the stripes go away when you turn of the USRPs?
* Also, the stripes aren't there, either, when you use the Lime on the
same 1.011 GHz frequency, exactly?
My suspicion is that this is mostly USB3 emissions (those could be, but
not necessarily are, happening through the USRP itself, or through
cables, or through your host computer.
If your sampling rates allow it (they do, I think you're using 500 kHz
only¹), try to use a USB2-only cable or port and see whether these
disappear.
Also, are you using an external power supply for your USRPs? If this is
actually an interferer, it might as well be some periodic behaviour of
the power supply.
Best regards,
Marcus
¹That's a sampling rate that should work on B200 and B20xmini, but it's
uncomfortably low – try with 1 MHz and host-side resampling, maybe?
On Wed, 2019-12-18 at 21:28 +0300, Геннадий Казачёк via USRP-users
wrote:
Hello, Sam!
No, I use two devices as transmitter and receiver and third board I
use just to observe sonogram.
Pulsations exist on both b205 and b210 devices if I use them as a
transmitter and not exist if I use as transmitter another vendor's
device - LimeSDR.
All 3 USRP devices are industrial with metal case, and LimeSDR is
not.
On Wed, 18 Dec 2019 at 21:26, Геннадий Казачёк <
gena.kazac...@gmail.com> wrote:
All 3 USRP devices are industrial with metal case, and LimeSDR is
not.
On Wed, 18 Dec 2019 at 21:25, Геннадий Казачёк <
gena.kazac...@gmail.com> wrote:
Hello, Sam!
No, I use two devices as transmitter and receiver and third board
I use just to observe sonogram.
Pulsations exist on both b205 and b210 devices if I use them as a
transmitter and not exist if I use as transmitter another
vendor's device - LimeSDR.
On Wed, 18 Dec 2019 at 18:49, Sam Reiter <sam.rei...@ettus.com>
wrote:
Just to be clear, you see these pulsations when transmitting
with a b205mini, but not with the b210?
Is the b205mini a bare board or an industrial model with a case
and aluminum heat sync?
Sam Reiter
Ettus Research
On Wed, Dec 11, 2019 at 11:48 PM Геннадий Казачёк via USRP-
users <usrp-users@lists.ettus.com> wrote:
Hello!
I'm trying to build QPSK based system on GNURadio.
I'm using two USRP B205-mini boards as transmitter and
receiver, also I got B210 board that I run gqrx on to watch
what is really going on.
I noticed a strange behaviour on my tests, so I began to
investigate it and ended to a very simple graph, that is in
attachment. On a frequencies that are multiple of 10Mhz, like
1020Mhz all works like expected and sonogram looks good. If I
tune to any other frequency, even 1Hz more or less, the
sonogram is full of pulsations and frequency of that
pulsation is depends of exact tune frequency. I attached some
screenshots of that pulsations.
On receiving part that pulsations cause many errors while
decoding.
I got another board, LimeSDR-Mini, and no such behaviour
observed while running graph on it.
I wonder what is going on, and how can I fix this problem.
Thank you.
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