This page is concerned with improving the Leak 'Troughline' tuner.
click right button on your mouse, then 'view image' to see enlarged view of circuit diagram.
The problem is that my version of this superb tuner is mono only, and it doesn't have a stereo decoder, or a multiplex signal output (one that contains both signal channels and a pilot tone, @19kHz). I will have to take an output from the tuner, and feed it into an external decoder; I have a Hitachi FT5500 I can use as a donor.
At Christmas, whilst shopping for food in Tesco's, I spied an FM transmitter, the kind one plugs into a sound source, and it sends out an FM transmission at any frequency between 87.6 and 107.9 MHz. Range is only 5 metres, but fine around the house. I am currently using it to assess the BBC's Radio3 programmes broadcasting in HD, at 320kb/s, and even on the computer room system, it sounds pretty good. Certainly better than a straight FM broadcast.
Makes me wonder if this is the way to go, with a better transmitter, so even if the government switch off the FM band, or let others have it, I can still have music via my tuners!
The batteries (2 x AAA) have just run out, they didn't last long! but I found a little charger type supply, which I plugged into the transmitter, et voila, sounds again, but, accompanied by mains hum. Into the bag of bits for a capacitor, chopped and stripped the wires, added the cap (0.47µF poly) and hum gone, just a little residual 100/150Hz to deal with, maybe a smallish value electrolytic will do.