Originally Posted by
SMSPower.Org Forum User
I don't have one but I know Brazil operates on a weird variant of the PAL system we have in the UK, making it more like NTSC but with less of its problems. The page here tells me that the base frequency (with the chrominance) looks like NTSC and the colour subcarrier is PAL-like but only works on Brazilian TVs - so you need a TV with some NTSC compatibility to get the black-and-white picture.
When I tried (and failed) to get my Japanese SMS to work via RF, I had to use the VHF band frequencies, as opposed to the UHF that UK TV uses - if your TV doesn't support that (and for 99.9% of people it doesn't have to) then you might get nothing.