These are reputed to be excellent receivers, but as with other old technological marine items (such as the old 'spinning' diode depth sounders, and my ancient Kenwood receiver) they are more curiosity than commodity. As Haiqu says above, they are of little practical use and have been superceded by much better radios for very little money.
They are not old enough to be worth a lot and I would suggest they are probably only worth a few pounds in a car boot sale.
It's a sad tale I'm afraid for something which, 40 years ago, was the duck's nuts in modern kit.
"if at first you don't succeed....Redefine success"!