This weekend I put some trendy LED striplights in my kitchen. But when I switch them on I have interference on my old Tandberg FM portable set. It's a sizzling/whooshy noise, not like mains hum. The LEDs are powered by something calling itself an "Electronic LED converter" which claims to be a switch mode power supply. If I unplug the LEDs from the PSU the interference stops. The radio is using its own telescopic aerial. Does anyone have any ideas about fixing this please?