All certifications are valid for the Decade and the BVE(Broadcastvision) but based on the confusion with the CZH-05B in the USA with multiple numbers and the one and seven watt CZH 07B as part 15 the certifications with the FCC are truly screwed up. I think only one number got it right with the FCC as part 73. But if it carries a part 15 number it isn't wrong in my mind to assume legal to use. Same with the Scosche that Carl mentioned.
Mark mentioned The Retekess TR508 FM Transmitter, and today during an exploration of the Retekess website I noticed the specs for this transmitter indicate the pre-emphasis is set at 50-us, the European standard, with no indication that it can be set to the North American 75 us standard. However, Model No. TR509 is set for 75-us pre-emphasis, as is model TR 502.
Two other models, TR505 & TR501 are unspecified regarding pre-emphasis.
Model TR509 mentions being "Approved" by the FCC and IC, but does not expressly mention being certified. Model TR502 makes no mention of the FCC (unless I missed it).
@carl-blare Trouble is do the receivers do the de-emphasis? That's the question. I don't think there's a regulation that they have to. It's voluntary. I think by listening to radios a lot don't.
I can adjust EQ(bass mid treble) at the processor like Sean Cuthbert which I am using so if a transmitter has 50uS you can compensate at source or processing if sounds like it needs it.
Mark, you raise an interesting question about FM receivers. While the FCC has made 75-us pre-emphasis standard at the point of transmission, I think de-emphasis in receivers is voluntary on the part of manufacturers, although it would make sense for de-emphasis to be present. On the other matter, you are most likely right that a 50-us transmitter could be boosted using an outboard frequency equalizer, so long as the take-off point comes close to matching.