Peter Parker (Amateur call sign VK3EY) in Australia tested my newly released WSPR transmitter.
Check out his review here: https://www.youtube.com/watch?v=Jpt9z4WJUDA
Besides testing it in several Maidenhed grids he goes in to the construction of the low pass filter and other details.
In typical Peter Parker fashion it is filmed outdoors by the Australian sea front and explains potential complex stuff in a very clear and easy to grasp way.
If you haven't watched his channel do check it out if you are a Radio Amateur as he has created lots of great content over the years.
Lastly ,please note that the Mezanine board, USB cable and Low Pass filters are separate Items and are not included with the purchase of the WSPR-TX_LP1.