Ask Slashdot: How do I disable a radio credit card?

Keybounce writes: So, like most of you, I recently got a new credit card with a chip in it. I was not worried about that — I know the chips are harder to copy and counterfeit.

But I recently discovered that the card is also a radio card — swiping it near the screen caused an message to show up on the reader. In this case, it told me to use the chip reader instead — but this means it has an active radio signal, and could be "hacked" — stolen by someone with the right device.

How can I prevent this? Is there anything I can do that will disable the radio signal and still leave the chip functioning?