405 lines from Raspberry Pi 5

[ppppenguin]

Standard modulators are designed to work with modern(ish) TV systems. System A 405 not only has AM sound and +ve vision modulation but also a unique 3.5MHz sound spacing. This has not been possible to achieve with a single modulator. Hence the use of separate vision and sound modulators in the Aurora and Hedghog. If there are standard modulator hats it might be possible to use two of them. The combining network is just a few resistors.