The FCC has banned all wireless use above 700MHz. For the Sennheiser wireless that would be the “C” block. To replace the “C” block Sennheiser has added the “G” block. Sennheisers “A” block covers 518-550MHz, the “B” block covers 630-662MHz and the “G” block 470-512MHz.
UHF or Ultra HIgh Frequency is the most used. I think you are referring to the old VHF or Very High Frequency systems. You are much better off buying a frequency agile system than a single frequency system as you can do frequency scans in the area you’re at to find a clear path. What works in “NY” may not work in “LA”
There are also frequency charts for the US & overseas on the Sennheiser website. Nothing is absolute or carved in stone as far as clear RF paths are concerned. It is very hit & miss.
Eric