[pups] PDP-11 / vacuum tube interface

Dear all, (This has got to be the strangest cross-post I've ever done.) I have just taken a bet from a friend to challenge my geekiness. I was telling him about my love of Vintage Technology and he proposed that I combine two hitherto separate hobbies and see what happens. The topics: the DEC PDP-11 minicomputer (vintage: 1970s) and vacuum-tube ham radios (vintage: 1960s). I do sincerely apologize for cross-posting, but I am rather younger than either of these technologies (vintage: 1984) and this seems like a monumental challenge. My question for y'all: how could I possibly design+build a project that uses both of these technologies? My thought is to port some radio receiver Digital Signal Processing (DSP) application into PDP-11 assembler, compile and run it via emulator on my PC, then use it with the vacuum-tube regenerative receiver that I built a few years ago... Does anybody know if PDP-11 UNIXes even had the capability for a "sound card"? Or, to get ambitious, I would LOVE to design some interface circuitry between PDP-11 digital circuitry and vacuum-tube electronics... The challenges are legion: the tube side of the circuit operates around 350V DC levels with radio-frequency (RF) signals at 7 MHz (almost the clock rate of some PDP-11s!) and I don't have the DEC Handbooks, but I'm pretty sure that even those ancient pre-TTL circuits operate below 350V! So... any, er, "ideas"? Best regards, Ross Tucker