Portsdown 2019

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The Portsdown transmitter has been designed to provide an easy way to “get on air” with Digital ATV at a relatively low cost covering all of the commonly used modes so enabling it to be used on ATV repeaters but also for RB-TV Dx working.

This guide is in a number of sections which cover detailed descriptions for hardware and software, how to build and configure the system, some advanced features and an FAQ.

The 2019 Portsdown is significantly different to previous versions in that the system no longer uses the custom built Filter Modulator card which has been replaced with an off the shelf LimeSDR Mini.

The LimeSDR Mini plugs in to the Raspberry Pi USB port, preferably via a powered USB hub and produces an RF outut from ~ 30MHz to 4GHz.

Overall the LimeSDR Mini is similar in cost to the FM board as you no longer need an ADF4351 LO module and an LO filter PCB and is available from the BATC shop https://batc.org.uk/shop/limesdr-mini/

Portsdown 2018

If you would still like an FM board, we suggest you post on the wanted section of the forum - https://forum.batc.org.uk/viewforum.php?f=14 - or blank PCBs for home construction are available here - BATC shop item 10.

All the wiki information on previous version of Portsdown are available here...


Hardware System Diagram

Here is the latest system diagram. Note that only one of the displays is required; either the 3.5 inch or 7 inch and the digital variable attenuator is only required if you want fine (<3 dB steps) control over your PA drive levels. The Lime Gain control on the Portsdown can be used to set the coarse output level.

20190120 Portsdown 2019 Block.jpg

Building the system

The Portsdown 2019 uses the majority of the 2018 Portsdown hardware.

Portsdown 2019 Software

The Portsdown 2019 uses the same software as later versions of the Portsdown 2018 system which is known as Portsdown 2018/2019 and is based on the Rpi Stretch operating system.

Initially configuring the system

Waveshare 3.5 inch screen

To get started, once you have an SD card with the Portsdown 2019 software loaded, simply put the card in the SD slot on the Rpi.

If you have a Waveshare touch screen the Portsdown 2019 software is pre-configured ready to use and no initial configuration is required. Connect the Waveshare 3.5 inch touchscreen (being careful to align the pins correctly) and apply power to the Rpi and the user interface should appear.

Element 14 7 inch screen or headless operation

However if you do not have a waveshare screen or you wish to enter the system advanced set-up pages you will need to do an initial setup - see this guide for more details: Initial setup 2019

Controlling the Portsdown 2019 system

Once the system is configured, you can control the Portsdown transmitter in one of 2 modes: by the use of the touchscreen or through the console using a second computer.

  • Touchscreen mode How to use your Portsdown transmitter using the Touchscreen LCD only
  • Console mode Use this mode to configure your Portsdown and change pre-set configs (such as SR and Freq) used in touch screen buttons.
  • Changing system setup How to change Portsdown transmitter settings when in Touchscreen mode
  • QPSKRF or Ugly mode Notes on this special test mode and the limitations when using it
  • Setting up the WiFi How to set up the WiFi on the RPi3 Portsdown Transmitter

Advanced features

Portsdown 2019 is not just a DATV transmitter but has several advanced features which are or may be available in the future:

On line support / social media

There is a Portsdown area on the BATC forum where the BATC core team and wider ATV community will answer your questions and posting results of the latest builds and on air tests. https://forum.batc.org.uk/viewforum.php?f=103

Note that the BATC core team do not regularly visit Facebook pages - time is just too short to monitor everything and it's not easy to follow threads on Facebook. If you need a question answered please post on the BATC forums first.

Additional information

Filters and driver amplifiers are not part of the Portsdown project but VERY important

The Portsdown user's community including a map showing where user locations