Improving the LimeSDR Performance with Portsdown Buster
Posted: Thu Feb 13, 2020 10:19 pm
The new Portsdown Buster build is designed to be used with the LimeSDR Mini running custom DVB firmware. I have now completed initial testing of this build (202002140) and am pleased to report that it resolves many of the issues (some modes not working, transmission breaks, etc) of the old Portsdown Stretch build.
Additionally, it supports the transmission of high SR DVB-S transmissions (up to 10 MS, if you must), so is suitable for transmitting to many of the existing ATV Repeaters. The usable DVB-S2 SR is limited to about 2 MS.
The one drawback is that the LimeSDR Mini needs to have the custom DVB firmware loaded, and so cannot be instantly used to transmit with other applications such as SDR Console. However, you can reprogram the firmware easily back and forth (Menu 3, Lime Config) and it is EEPROM based, so each LimeSDR Mini has a lifetime of at least 10,000 re-writes.
I have optimised the DVB-S2 modes for QO-100 use. The 333 KS FEC 1/2 transmission will transmit good SD pictures and only needs 1 dB S/N for reception, so can be transmitted with lower power or a smaller dish. The video source can be the Pi Camera, the EasyCap (Composite Video) or the C920 webcam.
There is no upgrade path from Stretch - you will need to build a new SD Card. There is a Wiki page listing the working modes here https://wiki.batc.org.uk/Portsdown_2020_Buster_Software and the build instructions are here https://github.com/BritishAmateurTelevi ... own-buster.
Modes not listed on the Wiki page have not been tested, so please don't complain that they are not working. The software will not support the LimeSDR USB, webcams other than the C920, or the Raspberry Pi 4. It is hoped to support the LimeNET Micro and LimeRFE amplifier as development progresses.
Please report your experiences with this build in this topic.
Dave
Additionally, it supports the transmission of high SR DVB-S transmissions (up to 10 MS, if you must), so is suitable for transmitting to many of the existing ATV Repeaters. The usable DVB-S2 SR is limited to about 2 MS.
The one drawback is that the LimeSDR Mini needs to have the custom DVB firmware loaded, and so cannot be instantly used to transmit with other applications such as SDR Console. However, you can reprogram the firmware easily back and forth (Menu 3, Lime Config) and it is EEPROM based, so each LimeSDR Mini has a lifetime of at least 10,000 re-writes.
I have optimised the DVB-S2 modes for QO-100 use. The 333 KS FEC 1/2 transmission will transmit good SD pictures and only needs 1 dB S/N for reception, so can be transmitted with lower power or a smaller dish. The video source can be the Pi Camera, the EasyCap (Composite Video) or the C920 webcam.
There is no upgrade path from Stretch - you will need to build a new SD Card. There is a Wiki page listing the working modes here https://wiki.batc.org.uk/Portsdown_2020_Buster_Software and the build instructions are here https://github.com/BritishAmateurTelevi ... own-buster.
Modes not listed on the Wiki page have not been tested, so please don't complain that they are not working. The software will not support the LimeSDR USB, webcams other than the C920, or the Raspberry Pi 4. It is hoped to support the LimeNET Micro and LimeRFE amplifier as development progresses.
Please report your experiences with this build in this topic.
Dave