Nice. That was an innovation in its time, 1990s, just the whole unit, there was nothing else like it at the hobby level, the big frequency display and the switched capacitor audio low pass filter, with a hard cutoff after 15 khz.
Other stereo FM transmitters at the time had a big problem with pilot and subcarrier interference, especially due to CD audio, causing stereo light flashing and sibilance. That filter went a long way to lowering it. I could see adding pre-emphasis control, even an active soft clipper for the highs, which it may already have inside.
Ah, nostalgia.. Ramsey was a great experimenter and hobby company. Now Ramsey is industrial electronics, if it's even the same company called Ramsey.