[SiriusHardware]

Welcome!

Weighing up the likelihood that every single radio in your collection has developed a roughly similar fault while standing unpowered and doing nothing, I have to say that this sounds unlikely. For a start, I must ask if you are using a common aerial for all of the sets.

How long have you been away? Broadly, two things have happened since you have been away.

One, broadcasting on long, medium and short wave has gone into steep decline. There are nothing like the numbers of stations on Medium wave, for example, that there used to be.

Two, sources of interference to those bands have increased greatly, computers, routers, power line network adaptors, switch mode power supplies now power everything, and even modern lighting can now render medium and short wave almost unlistenable. If you haven't turned a short-wave radio on for a couple of decades I imagine things will be very different now to how you remember them.