"All well and good but would not work on what this thread is about"
I'm not so sure, it just might be possible. That's why I showed the image with my current cooling solution.
I agree that with the conventional HAT design, which sits directly on top of the Pi board this would not work. That would fatally interfere with the cooling, whichever way you try to cut it.
However, this tower is hands down THE BEST cooling solution for the Pi4 (check out Christopher Barnatt's video on this cooler and how it compares to other solutions:
)
So I thought it might be worth exploring at this early stage, whether the AstroHAT can be designed in a way that allows incorporating this top of the line cooler for the RPi4 into the assembly.
I just think that might be possible, all that is required is to add some GPIO connection extension adapters that allow it to be moved up above the cooler. The 3D designs can easily be modified to make a case that incorporates the HAT with the cooler sandwiched in between the HAT and the Pi4 board and forming essentially a wind tunnel the cooling air is being sucked through, thus cooling the Pi4 and the HAT at the same time.
Worst case scenario, one can just use a cable to connect the HAT to the PI4 board (
core-electronics.com.au/raspberry-pi-b-g...-cable-40-pin-6.html ), but having a solid GPIO extender of the correct length would be preferable. That must exists somewhere.
It may be sufficient to stack 2 of these connectors on top of each other to clear the tower:
cnclablb.com/raspberry-pi-gpio-tall-header-2x20.html
I would LOVE to have that construction on my rig. At the moment, I have 3 power lines running up the rig, one for the 12V needed to run the mount and the dew strips, one to power the USB hub and one to power the RPi4. If I could replace that with a single power line running to the HAT/RPi4 and everything else being powered off that, that would be ideal.