CRT TV & 240p test suite

[Shadow_Zero]

As an intro;
Info page: http://junkerhq.net/xrgb/index.php?title=240p_test_suite
Download page: https://artemiourbina.itch.io/240p-test-suite
Developer: https://shmups.system11.org/viewtopic.php?f=6&t=35554
Some 240p info: https://www.hdretrovision.com/240p
Interesting article: https://www.inputmag.com/...-240p-test-suite-can-help

So I'm fiddling with the 240p test suite on my PAL Wii's and Sony KV25FX20B and Philips 25PT4458 (European tv's), and notice when I set the test suite on 240p I have overscan, and on 288p I have black borders:
https://i.imgur.com/UQQxJ8Kl.jpg

versus
https://i.imgur.com/RWsLscll.jpg


What's the reason for that??

[Segasonicfan]

As an intro;
Info page: http://junkerhq.net/xrgb/index.php?title=240p_test_suite
Download page: https://artemiourbina.itch.io/240p-test-suite
Developer: https://shmups.system11.org/viewtopic.php?f=6&t=35554
Some 240p info: https://www.hdretrovision.com/240p
Interesting article: https://www.inputmag.com/...-240p-test-suite-can-help

So I'm fiddling with the 240p test suite on my PAL Wii's and Sony KV25FX20B and Philips 25PT4458 (European tv's), and notice when I set the test suite on 240p I have overscan, and on 288p I have black borders:
https://i.imgur.com/UQQxJ8Kl.jpg

versus
https://i.imgur.com/RWsLscll.jpg


What's the reason for that??

This is common for PAL, since the resolution is different than NTSC (lower vertical height).  I dont live in europe, but I imagine if you have an old PAL TV it doesnt have the borders because the resolution is correct for their own signals.