BATC Forum

I have just published a software update for the Portsdown 2020 (Raspberry Pi 3). This update (202102160) brings the System and LimeSDR software up-to-date and introduces an experimental DVB-T transmit capability using the LimeSDR Mini.

DVB-T transmit only works with the LimeSDR Mini loaded with firmware version 1.30. NOT the special DVB firmware. It is also limited to H264 encoding, not MPEG-2. The Guard interval is fixed at 1/32 and only QPSK is available. It has been tested at bandwidths between 250 and 1000 kHz. There is no DVB-T receive capability in this software (unlike Portsdown 4). Thanks to Charles G4GUO for providing this capability.

Note that (as with DVB-S/S2) there is a significant calibration power output spike that occurs a few seconds before the PTT line becomes active. However, it is more significant because the DVB-T power output is lower than that for DVB-S/S2.

The full list of updated features is:

• New builds based on Raspios 2021-01-11
• Update Limesuite Version to 20.10
• Tidy LimeFPGA builds
• Display Required TS Bitrate on Info Screen
• Improve Jetson HDMI video quality
• Initial LimeSDR Mini DVB-T transmit capability

As usual, you can update from Menu 3, Check for Update. The update will take a while as there are a lot of system upgrades to be applied. Just start it off and come back after a cup of tea/coffee.

Please report any bugs here.

Dave, G8GKQ

Hi Dave
Today I had fun viewing and controlling G8XTW's spectrum analyser over the internet my dvbt signal was produced with the Portsdown 2020 and a Lime mini into a CML class A amplifier at 437MHz producing 20w O/P. I have attached a screen grab from Phil's analyser.
We then decided to take a look at the dvbs signal from the same setup with a surprising result the dvbs signal appeared at about 1.1MHz low and with an unmodulated signal at 437MHz. Has anyone else observed this or is it something strange with my gear.
LIME MINI Test report reads Hardware V1.2 Firmware V6 Gateware V 1.30 and the last 4 tests show Failed

73 Arthur G4CPE

Did a force update today and both dvbt and dvbs now working again.
73 Arthur
G4CPE

Hi Arthur

I was finally in a position to test and try to reproduce this problem today. I could not see anything amiss.

Please let me know if it happens again and we'll try to track down the cause.

The fact that the LimeSDR fails the last 4 tests is not unusual. It is normally caused by the gain of the TX and RX channels being slightly out of tolerance. You may find that it passes the tests when cold and with nothing connected to the SMAs.

Dave, G8GKQ

Hi
I have been trying to get my Portsdown 2020 to transmit DVB-T
When I try to update the portsdown software it says that I have version 202102100 loaded and that it is the latest version
When I look at lime config it says I have version 1.29 and that it is the latest version.
What am I missing? There must be something I am not doing as Alan G4HND has just done his Portsdown 2020 and I have received pictures from him.
Jim

Mine is fine. Are you sure it isn't working? What input have you selected?

Hi jim

I recall that there may have been an error that prevented the update process working properly around then.

Please try "Force Update". It will take a long time, but stick with it and let me know how you get on. Once that is successful, you'll be able to update your LimeSDR.

Dave

rebuilt my card from scratch and now it's working fine
Jim

I tried force update but to no avail so I formatted the SD card and rebuilt it - now version 202111101
works fine now.
The card must have become corrupted
Jim

Hi Dave.

Mine updated fine (but not tested yet, booted OK) but now (still) reports Version XXXXX1101 and not the XXXXX2160 version you stated.

10 minutes duration, by the way.

73, Mike