Langstone SDR unstable

[K2ORS]

Hello the list,
I put together a Langstone SDR and it seems to either not load or crash under certain conditions.
Often I get a message after booting "Lang_RX.py Not Responding" sometimes also "Lang_TX.py Not Responding"
When it does load, on receive, the waterfall will freeze up after a period of time and the touch screen becomes unresponsive.
About half the time pushing the PTT switch will not transmit and will cause the program to become unresponsive forcing the need for a power down reboot.
./Pluto_Test says that I'm only getting ~660-680 calls per second as opposed to the standard 1900.

To test the Pluto, I connected it to a WIN10 PC running SDR Console, and it responds normally.

Any thoughts?
73 & Tnx Warren K2ORS
member U.K. Microwave Group

[G8GKQ]

Warren

I would suggest that you start by checking the power supply voltage measured between pins 6 and 2 of the GPIO connector on your Raspberry Pi. It should be a stable 5.2v.

Dave, G8GKQ

[K2ORS]

Hi Dave,
Thanks for the reply, the voltage on the Pi is 5.2V.
The big news is that by plugging the Pluto into the USB 2.0 port (black) on the Pi it seems to be very stable now!
I previously had been running the Pluto on the USB 3.0 port (blue) which seems to be the cause of my problems.

73 Warren K2ORS

[g4eml]

The Pluto should work fine on any of the USB ports. However we do know that the Pluto is very sensitive to supply voltage and ground loops. Most likely changing the USB port resulted in a better power supply.

If you still have problems It might be worth powering the Pluto directly from the 5V supply using the auxiliary power connector.

Unfortunately because the Pluto is so sensitive there is no one solution that suits everyone. It involves a bit of trial and error.

I believe the new Rev D version of the Pluto is supposed to be better in this respect but I have not had chance to try one.

Either way I am happy that you got it working.

My development Langstone will happily run all day long without problems. That powers the Pluto using the second connector but also has additional ground connections due to it being mounted on a metal chassis plate.

Colin G4EML.

[g4eml]

Warren,

One request, now it is working more reliably can you please re-run the pluto_test and see if the throughput has improved. It would be useful knowledge to add to the debugging notes.

Colin.

[g8gtz]

Warren

Have you done the ground modification described on this page: https://www.f5uii.net/en/transmit-datv- ... lutodvb/4/

It seems to cure a lot of instability problems and USB crashes.

73
Noel - G8GTZ

[K2ORS]

Noel,
Many thanks for the info on the F5UUI web site, very good source for Pluto

[K2ORS]

Hi Colin,

./Pluto_Test now reports around 540 calls per second when connected to the USB 2 port (was 640-680 on USB 3)
Also did a test with Pi connected to USB 2 and an external supply connected to the Pluto, result was between 411-414 calls per second over 4 trys.
However, the Langstone is much more stable and reliable than when connected to USB 3 even though the throughput was higher on USB 3.

Vy 73 Warren K2ORS

Warren,

One request, now it is working more reliably can you please re-run the pluto_test and see if the throughput has improved. It would be useful knowledge to add to the debugging notes.

Colin.

[g4eml]

Hi Warren,

Thanks for the reply.

I don’t understand why the throughout would be so much lower than on my system. There must be something else going on that I don’t understand! That test was made to identify network problems but maybe something else is also having an effect on the result.

As long as it is working OK I would not worry too much.

Colin.