Use of the NVIDIA Jetson Nano for DATV

[G8GKQ]

Hi Tim

Last time that I checked, the LimeSDR Mini GPIO functionality was as described here: https://wiki.batc.org.uk/Using_LimeSDR_ ... iple_Bands

Note that, using these outputs (which are not buffered), puts your LimeSDR at greater risk of damage from switching transients, so we recommend using the RPi GPIOs instead.

Dave

[G8GKQ]

Sorry Tim

Just noticed the Topic title! The Portsdown does not control the GPIO lines of a Lime connected to a Jetson, only a Lime connected to the RPi.

Dave

[G4WIM]

Hi Dave,

thanks for the clarification - so as an interim HW fix I'll drive my PA key line manually.

Regards Tim

[G8PEF]

Dave, G8GKQ, said (inter alia):

"The NVIDIA Jetson Nano can be used to drive a LimeSDR as a very capable DATV transmitter. The on-board hardware H264 and H265 encoders are particularly good."

I've been looking at the Jetson Nano specs, and it's quite an impressive bit of hardware for its size/price point...
I'm curious as to how hot it gets when transcoding from H264 to H265 and driving a Lime Mini - does it require fan cooling?
Also, what is the current draw (at 5V) in this configuration.

I note from the website that it is possible to power it at 48V via the Ethernet port if you have a POE injector - presumably, the regulation down to 5V is not on the board, and requires additional hardwRe at the Nano end?

John, G8PEF

[G8PEF]

Also, Dave, I meant to add to the previous query, if the Nano is being used with the lime mini, is the raspberry Pi still required, or have you installed the software (and the touchscreen) directly on the nano?

73
John

EDIT: Please ignore this supplementary question; I've found that if I put my reading glasses on and pay attention, it's already covered in the original post

J

[g0mjw]

Dave, G8GKQ, said (inter alia):

I've been looking at the Jetson Nano specs, and it's quite an impressive bit of hardware for its size/price point...
I'm curious as to how hot it gets when transcoding from H264 to H265 and driving a Lime Mini - does it require fan cooling?
Also, what is the current draw (at 5V) in this configuration.


John, G8PEF

Yes. Well I suppose strictly not but it gets hot. Max power is 10W, so 2A plus whatever your USB devices need.

[G8PEF]

Thanks for that, Mike. So, the 10W figure quoted is a maximum - even with all the cores running flat out? That’s quite impressive in itself.

73
John

[G4WIM]

My Portsdown, LKV, Nano and Lime combination had been working very nicely then it stopped.

By stopped I mean the Portsdown can still control the Lime via the nano but looking at MT the 'program' field is blank as is the provider and the codec shows VH264 + MPA. The screen also shows no video or bad codec / PID

My first though was that my LKV had stopped - but no as VLC can display it ok - albeit at 30FPS - maybe this is the problem ? Couldn't find a way to change to 25FPS anyway.

So I did a fresh install on the Nano and for good measure on the RPI. All seemed to go ok, but during the Nano process of installing F5OEO code it did ask me if I wanted some updated FFMPEG stuff - I declined.
I also re-flashed the LKV as directed in case something had become corrupted.

RPI controls the freq and the Nano / Lime just fine - it's just the video path which seems broken for whatever reason.

Any idea how to debug / fix ?

EDIT - it might be related to the fact I have two Portsdowns on my network, one for the Nano / Lime and another for 24cms using the Portsdown 1249MHz tx.

I now find that the 24cms Portsdown RPI can at least control the Nano / Lime but the original Lime / Nano Portsdown cannot see the Nano / Lime despite having the correct settings etc and working fine before.

Smells like a conflict between the the two Portsdowns even though I only have one of them switched on at any given time.

Regards Tim

[M0SKM]

Hi Tim,
If you edit jetson_nano.sh with Dave's basic setup for 500k/s and run it direct do you get video then?

At least it will eliminate the Portdown software.

./jetson_nano.sh

No expert just running the same system.

As an aside I got through three broadband routers before I found one which would network the video. This might be useful to someone adopting the LKV373A and Nano.

Steve

[G4WIM]

Thanks Steve,

I'l give that a shot and put the RPI and usb mike directly into the Nano and edit the script accordingly - just updated my post above with a bit more info.

Regards Tim