Lime mini and DVB Fw

[mm0mgb]

Hi all,

I am stumped and have searched the forum for a solution to no avail.

I have upgraded my set up to ports down 4 with new pi4 sd card and latest software. Lime mini allowed 1.3 fw and produces an output but noise floor not far below the wanted signal ( looking at this on spectrum analyser)

If I upgrade to the dvb fw I don’t get an output, I’ve set calibrate every TX?

I also observe that some modes on the lime mini setting run for around 10 secs and then it looses modulation.

I have run out of talent to work this out! Is the pd4 really for the Pluto?

Andrew Mm0mgb

[G8GKQ]

Hi Andrew

Portsdown 4 should work as well (if not better) with the LimeSDR Mini as the Portsdown 2020 does.

The first thing that I would do is check the supply voltage at your LimeSDR. You can measure it on the edge terminals. If you measure between the VCC5P0_USB terminal (the right hand one on the top edge of the board) and the SMA outer, you need 4.90 volts for reliable operation.

You are right to select "Calibrate Every TX"; that elimantes another source of problems.

Dave, G8GKQ

[G7JTT]

Have you set it to lime dvb on the main menu ? I've been caught out by this before.

73 John

[mm0mgb]

Hi thanks for getting back to me. I thought I initially had an amplifier problem but after exhausting that line I started to look at the lime output. I soldered 5v lines directly from the psu ( pc 750 watt supply) and reading 4.91v on the lime board.

I tried the dvb firmware upgrade then selected lime dvb on the main menu but no output??

Tried various fec and data rates but I started going round in circles and I’ve lost the plot

[mm0mgb]

Meant to add tried my spare lime with same results.

A

[G8GKQ]

I would suggest going back to the 1.30 firmware on the Lime. Then select LimeSDR Mini as the output device. Disconnect all other USB devices, then try H264 Test Card, 333 kS.

Dave

[mm0mgb]

Having changed the firmware to the lime dvb it won’t let me reload the 1.3 version, I can only do that via lime suite.

I’ve attached pictures of my output initially, the big wide form and after either seconds or a minute I get the sharp one. Same thing happens with 500kbs, flat top mountain for a bit then spike.

[G8GKQ]

The fact that it won't let you load firmware 1.30 is a clue to the problem. Could you give more details?

Dave

[mm0mgb]

I loaded my original lime mini with v1.30 via portsdown, then loaded the DV’s version. Not working so tried to reload v1.3 portsdown reported unsuccessful. I put the lime onto the pc and using lime suit got the info. It said no gateway nothing only it was a hardware v2. At this stage the lime had a steady green led.

Used program and it did its thing and loaded v1.3 with all the other fields looking correct.

Put the lime back onto the ports down and asked it for lime info and all fields zero tried the upgrade got the unsuccessful again?.

Went to lime fw info and it says no device available, replugged it and have as shown in photo back to where I was so it goes into TX but the signal isn’t far above the noise and I’ve shoulders. Changing the power level doesn’t seem to make any difference to the output, also signal collapsing again.

Your help deeply appreciated!

Andrew

[mm0mgb]

Should I be aiming to use lime mini or lime DVB? Suppose I should have asked that first. My old portsdown was a 2019 but I was getting drop outs in some combinations of sr and fec so I decided that with the rpi4 being a more capable platform and pd4 being the development project I had to go for it. Initially things looked good except I had strange Rf power fluctuations so I started to investigate and ended up back at the lime board.

If I now try and use the ports down to upgrade the firmware To 1.3 it is always unsuccessful and bricks the lime board until I use lime suite to reload it. Xyl is having a fit about this!!

Andrew