Portsdown 2019
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...
Specification
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.
