The TU-7-B sounds like the series of tuners for the BC-191/375 Signal
Corps/AAF transmitters. The range for this tuner is 4500kHz-6200kHz. I
didn't know that RCA made them... unless, of course, we're talking about
an entirely different TU-7-B. If there is a tuning chart on the front
panel that delineates the above frequency range and a row of what look
like banana jacks on the rear panel, then it probably is for the
191/375. The tuner may be in a transit case, which you'll have to
remove, first. Send along the pix.. please! Anything's possible!!

MTM wrote:
Hello............NG
Anyone know anthing about these radios..?

REL Tuner..?
RCA / Signal Corp. TU-7-B...?

Also few more unknown/ home brew radio sets..Pix available....
Let me know...