I think you'd definitely be out of luck using the internal tuner. Apart from the differing colour system, the frequency band and spacing is probably totally different too.
Also, not all PAL is the same when it comes to RF. There are different versions where the sound is modulated in different ways - you might get no sound, even with a UK Slingbox.
UK Slingbox (not sure about US version) connected to an STB using Video / Audio cables should work, as long as you can get the remote codes.


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