Yes, it's right.Given that 99% of USB FM tuners are using RTL2832U that remains, even in 2016, a problem for Mediaportal.
But no one made a bridge realtek api/directshow filters.
So it's not only a MP problem, but also a ProdDvb, DvbViewer, etc. problem.
There's no software, apart from that which use direct calls to the api, that can make full use of our rtl2832.
And that software cannot transmit on LAN.
Even under linux situation is even worse, because there's no dab support at all and fm (rtlsdr) has to be switched at boot time, because uses a different kernel module.
I agree that rtl2832 is so cheap and common that it would be a great step forward for MP, but, as mm1352000 said, it involves some serious (and very difficult) programming.
I do believe in what mm1352000 says, and even if you don't believe him, why nobody made this 'til now, if it was so simple?
Bye,
sdf