Software capabilities and issues

The latest Software for the Portsdown Transmitter is version 201703060 (the version is the issue date with an added 0-9 serial).

Simply update using the console menu or download from: https://github.com/BritishAmateurTelevisionClub/rpidatv.

This software supports the following:

Supported hardware

• Raspberry Pi 3 Model B, with or without a 3.5 inch diagonal Waveshare touchscreen.
• Alternatively, the TX can be controlled over the network from another computer.
• The use of a keyboard and monitor connected directly to the Pi is not supported.

The Pi will control an ADF4351 Synthesizer with a 10 or 25 MHz Reference Oscillator, and can accept video input from an EasyCap type USB capture device and from a Pi Camera.

Currently the Pi will output a dirty (ugly) QPSK signal on 437 MHz for testing, send I and Q signals to the Portsdown Filter/modulator board, and control a DATV Express in DVB-S mode.

For use as a basic DVB-S H264 LeanDVB signal monitor, an RTL-SDR is required.

Modes

• In IQ output mode, the Pi will encode the Pi Camera, the EasyCap or the on-board test card at up to 4 MS/s.

• In DATV Express mode, it will transmit MPEG-2 or H264 picures from the RPi Camera at 125 KS/s - 4 MS/s

• In "ugly mode" it will encode from these sources reliably at 125KS/s and sometimes at 333KS/s.

• In streaming mode, it will send RPi Camera pictures and USB dongle sound to the BATC Streamer, or to any other compatible streamer.

• With an added RTL-SDR, the included LeanDVB monitor receiver will display strong DVB-S H264 signals of up to 500 KS/s.

Issues

If an EasyCap device is plugged in, some Pi Camera modes do not work.

Future Enhancements

There is a very long list of things to get working properly. Here are the highlights:

• Streaming (with sound) from an external video input (EasyCap)
• Implement fix for DigiThin mode and test it.
• Provide a shutdown option from the touchscreen
• Adjust the Test Card sizes
• Display transmitted image on the LCD in all modes
• Add sound channel to H264 video modes

Version history

• Version 201612310 Introduced a blank background behind the receive display, which in now part of the core capability.
• Version 201701020 introduced automatic selection of EasyCap input and TV standard.
• Version 201701080 introduced installation of Waveshare Touchscreen drivers during install, disabled the screensaver and added a screen logo at next boot.
• Version 201701190 Added stability improvements allowing 4MS SR, increasing reliability and reducing lock-ups. It also adjusted the touchscreen display to be centered in the screen
• Version 201701230 Added an Advanced Setup Menu. The fallback IP address was disabled, and the update script made more resilient to internet connection problems.
• Version 201701270 Added the ability to set the reference frequency and power for the ADF4351. It also corrected the selection of Carrier and Carrier Null modes, improved band switching and added menu items for future enhancements.
• Version 201701280 Bug fix for new ADF4351 functionality introduced in 201701270
• Version 201702020 New version of pi-sdn for button-initiated shutdown without error messages. Install and update improvements to allow easier testing and subsequent fielding of development versions.
• Version 201702060 Introduced basic support for the DATV Express modulator board
• Version 201702090 Introduced support for updated DATV express_server software. PTT capability and full SR range.
• Version 201702100 Completed the DATV Express capability, including Port switching, and tidied the switching between touchscreen and console.
• Version 201702110 Bugfix for DATV Express
• Version 201702190 Enabled streaming modes, lip-sync for MPEG-2 and switchable viewfinder.
• Version 201703060 Added the capability to adjust the frequency and SR for the touch screen presets.

Last updated 7 Mar 17. DGC