LimeSDR Mini and Portsdown4

The place to discuss the use of the LimeSDR Mini for amateur TV applications
Post Reply
User avatar
i2NDT
Posts: 160
Joined: Thu Nov 12, 2015 9:26 pm

LimeSDR Mini and Portsdown4

Post by i2NDT » Mon Feb 21, 2022 3:28 pm

I would like to get in touch with other users of the Portsdown 4 - LimeSDR Mini combo to check some things like:

- transmission delay
I measured ~12 seconds from when I press the TX button to when the Raspi GPIO pin 40 (PTT) goes high, while in a 2019 post (related to Portsdown 2020) a delay of 7 seconds was indicated.
choosing "Never Calibrate" or "Calibrate if needed" doesn't change the delay...

- Lime firmware
testcard transmission with various SR and FEC works very well with firmware 1.30. however, when I load the DVB-FW firmware the Lime does not transmit a decodable signal by my MiniTioune. returning to 1.30 everything is fine.

- band viewer
it works, but it seems that the CPU and GPU of my Raspi are very stressed: after about 5 minutes of operation I receive the "excessive temperature" warning and when I check (M1=>Info) I see that the temperature measured by the Raspi exceeds 75° C.

thanks in advance!

i2NDT Claudio

PS
I plugged the Lime into one of the USB3 ports using a USB3 cable 30cm long.
I started my tests with an old version (Buster 202104...) and than upgraded to the latest 202201110 but didn't see any difference.
i2NDT Claudio
Dalmine, Italia

G8GKQ
Site Admin
Posts: 2798
Joined: Sun Mar 22, 2009 1:21 pm

Re: LimeSDR Mini and Portsdown4

Post by G8GKQ » Mon Feb 21, 2022 4:00 pm

Hi Claudio

Some of the easier questions to answer

I increased the Lime PTT delay to 12 seconds because some users reported that 7 seconds was not long enough. I think that the time taken before calibration can be variable depending on other parameters. I am about to remove the "Never Calibrate" and "Calibrate if Needed" options as they seem to have ceased to work properly since a LimeSuite software update.

Are you selecting "Lime DVB" as the output device once you have loaded the Lime DVB firmware?

Yes, BandViewer does work the CPU hard. It needs a heatsink or fan for sustained operation.

73

Dave

User avatar
i2NDT
Posts: 160
Joined: Thu Nov 12, 2015 9:26 pm

Re: LimeSDR Mini and Portsdown4

Post by i2NDT » Mon Feb 21, 2022 4:27 pm

thanks Dave!
...I missed the Lime DVB output...will try now!

Claudio
i2NDT Claudio
Dalmine, Italia

User avatar
i2NDT
Posts: 160
Joined: Thu Nov 12, 2015 9:26 pm

Re: LimeSDR Mini and Portsdown4

Post by i2NDT » Tue Feb 22, 2022 1:53 pm

GRRRRRRR!
unfortunately it doesn't work!
loaded the DVB FW and changed Output to Lime DVB but still no signal out.
I also checked the "Lime FW Info" but I get the same result as for the FW 1.30!
so I don't know if I have loaded the right firmware.

Claudio
i2NDT Claudio
Dalmine, Italia

Post Reply

Return to “LimeSDR Mini”