[Mondial]

Well, from the osc frequency readings to obtained, it appears the oscillator is spot on and can be eliminated as the problem. That, with the fact that you do receive the signal generator well at 1000 kHz points to the antenna circuit as the next place to look. The possible components here are the bandswitch, antenna coil, tuning capacitor, loop antenna and the connections between them.

Have you sprayed  the bandswitch contacts with contact cleaner and "exercised" it? Usually these switches have not been operated in years, and the contacts are coated with an insulating layer of tarnish. I am surprised that you don't get static noises when you rotate the switch though.