LimeSDR-Mini Problems with DATV-Express

The place to discuss the use of the LimeSDR Mini for amateur TV applications
g4ouk
Posts: 15
Joined: Fri Jun 27, 2014 1:30 am

LimeSDR-Mini Problems with DATV-Express

Post by g4ouk » Fri Feb 01, 2019 2:01 am

Hello Lime Fans,

Had my Lime Mini Board a couple of days and already I'm pulling my hair out. Before I say any more I just want to inform that I am using Firmware Version 5 with the V 1.2 Board. Using DATV Express Software v1.25LP12 the Latest. I keep getting a breaking up of the Transmit signal waveform which seems to correspond to varying Tx Queue. I get varying results depending which USB 3 Port I plug into. When I tried using a USB3 Hub the signal was all broken and horrible. Then I plugged directly into the PC USB3 Port and I get a proper waveform on the Spectrum Analyser but the Waveform Breaks up every second and seems to be in sync with the TX Queue vaying?? In desperation I tried a different PC, my i7 Laptop 10GB Ram but the same results.

Is my Lime faulty or the Firmware old?? Is Firmware 5 the latest and if not how do I update the firmware on the Lime Mini?

Both PC's I tired the Lime Mini on are both i7's with 8 and 10GB RAM and all have USB3 Ports as standard.

What can be causing this problem, I'm running out of ideas and it's late, don't want to be staying up late every night trying to fix it, help !!!! :cry:

Thanks Simon
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G4GUO
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Re: LimeSDR-Mini Problems with DATV-Express

Post by G4GUO » Fri Feb 01, 2019 9:41 am

The latest version of DATV-Express comes up with an Alert Box telling you if you have incompatible hardware.
If you are not seeing that message then the firmware is compatible.

My only suggestion is check the USB cable (if you are using one) and check there is enough power from the PC to the Lime.
I have a number of USB3 ports on my P.C and only one of them provides enough power (the one with the charging symbol on it)

- Charles

g4ouk
Posts: 15
Joined: Fri Jun 27, 2014 1:30 am

Re: LimeSDR-Mini Problems with DATV-Express

Post by g4ouk » Fri Feb 01, 2019 2:53 pm

Thanks Charles,

Yes I Tried all my USB3 Ports on both computers with similar results. I'll try using a separate power supply with my USB3 Hub but I don't have much confidence. I'll post again if that does not work. Just hope my Lime is okay, I may have to test against a friends Lime Mini.

Simon

g8vpg
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Joined: Fri Oct 11, 2013 9:35 am

Re: LimeSDR-Mini Problems with DATV-Express

Post by g8vpg » Sat Feb 02, 2019 12:22 pm

I thought I would add my observations of playing with the Lime SDR Mini over the past few cold afternoons. I have updated the Lime firmware using Portsdown to the recommended version.
With DATV Express v1.25LP12, it gives excellent results at low symbol rates. I have had really good pictures using 100ks/s H265. However, any attempt to run much more than 1ms/s causes problems. Either the picture pixellates badly with movement or the buffer rapidly fills up to 100%. This buffer overflow used to occur often with earlier versions using DATV Express and the only cure was a complete hard restart of computer and Express. I am using a one year old Core i5 laptop that is quite powerful. My video source is Vmix. I have tried powered usb hubs and plugging it in directly to the computer, but it doesn't solve it. I have also tried many combinations of video twiddle factor, GOP & B frames, but nothing seems to fix it. I wonder what settings those who have it working well have used?
With Portsdown, it works well up to 2ms/s, but doesn't want to know 4ms/s, which is what we have been told.
I think it is worth the money to be able to run 100ks/s H265 with a bandwidth of 120kHz and very good, if laggy video quality. No doubt these issues will be resolved as we all gain experience of the device.
73 Shaun.

g4ouk
Posts: 15
Joined: Fri Jun 27, 2014 1:30 am

Re: LimeSDR-Mini Problems with DATV-Express

Post by g4ouk » Sat Feb 02, 2019 1:43 pm

Hi Shaun,

Okay on updating the firmware of your Lime Mini, what Firmware version are you using? I am using Version 5. Regarding Symbol Rates I am trying it with our local repeater GB3UD at 4ms/s. G8KUZ is able to successfully use his Lime Mini with 4ms/s and we are both using the same software DATV Express v1.25LP12 and Windows Drivers. The only thing that could be different is the Firmware which is why I'm trying to find the latest version. We are both using i5 and i7 Intel Machines with USB3. Have tried multiple ports too.

Also how do I update the firmware if its old. I dont have a portsdown, only using the DATV Express Windows software. I have Lime Suite Installed so if any IT experts are around please let me know.

Thanks for your help.

Simon :roll:

G8GKQ
Site Admin
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Re: LimeSDR-Mini Problems with DATV-Express

Post by G8GKQ » Sat Feb 02, 2019 2:20 pm

Hi Simon

As far as I can see, you have the correct firmware and gateware installed. It is the gateware version that is critical (needs to be 1.27). Your windows screenshot shows the same info as the report on a correctly configured LimeSDR Mini on a Portsdown - see below.

Looking at when it was dispatched, your LimeSDR Mini would have been dispatched from the BATC Shop in this state, as Noel had spent some time getting them all to the correct standard to make it easy for Portsdown users. Note that the latest gateware version available online is 1.28, but this may not be compatible with Portsdown or DATV Express. Charles and I have better things to do than go chasing new versions when the old one works perfectly!

There is more information here: https://wiki.batc.org.uk/Using_LimeSDR_with_Portsdown. Sorry that I cannot help you with using the LimeSDR Mini with other software - my expertise is only that which I have gained through getting the LimeSDR working with the (Linux-based) Portsdown system.

That said, my general experience has been that power supply or USB3 driver issues have been responsible for the the majority of the sort of problems that you are experiencing.

Dave, G8GKQ
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g4ouk
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Joined: Fri Jun 27, 2014 1:30 am

Re: LimeSDR-Mini Problems with DATV-Express

Post by g4ouk » Sat Feb 02, 2019 9:12 pm

Hi Dave,

Thanks for confirming I have the latest version of Firmware 5 and Gateware 1.27. I'm trying to use 4ms/s H262 MPEG2 for our local repeater so maybe its a software driver issue with the Lime not being able to handle that amount of data through the USB3, very odd. So really until a software upgrade on DATV Express happens which can benefit from taking advantage of USB3 I probably won't be able to use my Lime with our repeater. I will test out using 2ms/s in the shack just to confirm that 2ms/s works okay, it should be fine on an i7 with DATV Express.

Thanks again for your help

Simon, G4OUK

G4GUO
Posts: 610
Joined: Tue Feb 16, 2010 12:51 pm

Re: LimeSDR-Mini Problems with DATV-Express

Post by G4GUO » Sun Feb 03, 2019 9:09 am

You will be waiting a long time as it is not a DATV-Express issue.
DATV-Express uses LimeSuite which is an interface library provided by Lime themselves.
My P.C is capable of well in excess of 4MS/s with a Mini.

- Charles

g0mjw
Posts: 788
Joined: Sat Sep 20, 2014 9:15 am

Re: LimeSDR-Mini Problems with DATV-Express

Post by g0mjw » Sun Feb 03, 2019 9:53 am

g4ouk wrote:
Sat Feb 02, 2019 9:12 pm
Hi Dave,

Thanks for confirming I have the latest version of Firmware 5 and Gateware 1.27. I'm trying to use 4ms/s H262 MPEG2 for our local repeater so maybe its a software driver issue with the Lime not being able to handle that amount of data through the USB3, very odd. So really until a software upgrade on DATV Express happens which can benefit from taking advantage of USB3 I probably won't be able to use my Lime with our repeater. I will test out using 2ms/s in the shack just to confirm that 2ms/s works okay, it should be fine on an i7 with DATV Express.

Thanks again for your help

Simon, G4OUK
Perhaps instead you should be thinking about reducing the bandwidth of the repeater and moving to H264? That would have several benefits, including increased sensitivity.

Mike

g8vpg
Posts: 306
Joined: Fri Oct 11, 2013 9:35 am

Re: LimeSDR-Mini Problems with DATV-Express

Post by g8vpg » Sun Feb 03, 2019 10:34 am

Just to clarify the matter, is it correct to say that the Lime SDR Mini should only be used with USB2? It seems odd that a new, current product would not be compatible with the latest USB standard.
Charles - would you share the settings you have used to get Lime working at 4ms/s or more?
73 Shaun.

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