RE: Gnuradio for Raspberry PI 4 and SDRPLay works well, but need documentation

[Getz, Robin]

On Friday, November 15, 2019 1:22 PM , Glen I Langston wrote:
[snip]
> I’ve not yet fully checked the SDRPlay for short term transients.
>
>Note that the Pluto SDR has no (or at least few) short term transients in the 
>RF.
> I did find the AIRSPY did have some transients that seem to be due to the 
> device.
> These occur a few thousand times a day, but for shorter than 100 micro 
> seconds.
> Total time on is less than a second a day.
> 

Glen:

I would be interested in what you mean by this. I assume it's mostly "anomalous 
data", and while it's "not right", you aren't sure if it is coming from the RF 
(air interference) or via some transport scheme issue.

If you have a bursty/intermittent adjacent channel (where adjacent can be 
within ~200 MHz of your LO, depending on your hardware), it could cause 
anomalous reception. (This highly depends on your external filters, and 
shielding)...

If you have bursty/intermittent data on harmonics of the LO (again, depending 
on your hardware, external filters, shielding, etc), it could cause anomalous 
reception.

If you have a ground loop, and someone next door turns on their electric drill 
(for example) - this could cause what appear to be receiver problems. (remember 
- you are pulling out signals at -100dBm, into 50 ohms, that is 6.324 µV(p-p) 
or 0.12648 µA(p-p)/ That is pretty tiny, and can be effected by lots of issues.

On AD936x based radios (Pluto, B200, E310, BladeRF 2.0 micro) there is the 
ability to set the Rx to an LFSR/PRBS (Pseudo-Random Bit Sequence), to verify 
"data", which I have run for ~ week with no lost/bad data, both at max rate 
(61.44 MSPS, checking in local in the FPGA), and lower over the various 
transport layers (~5 MSPS over USB and Ethernet), checking in a C application. 
I haven't done it in awhile - and have not gone all the way up to GNU Radio, 
but should be able to pretty easily ... More info at:
https://ez.analog.com/cfs-file/__key/communityserver-wikis-components-files/00-00-00-02-20/AD9361BISTFAQ.pdf

If you think you are seeing bad digital/transport data on Pluto - let us know 
so we can track things down. (it's been awhile since we tested this, and 
changes have been made, I will add this to the release test)
Any sort of anomalous device or transport issues - we can try to help look 
into. If they are anomalous RF issues - that's harder. 😊
Our goal is zero device issues all the time - the transport to any application 
should be rock solid.

Let me know.

-Robin

Also - if you are interested in only Rx (like I'm assuming), make sure to turn 
the Tx off.
https://wiki.analog.com/university/tools/pluto/hacking/listening_to_yourself