DJ wrote:

Speaking of hearing Christmas lights, a friend just got a radio and hears a
contant tick tick tick like a clock in the background. But, its not a
clock. ANy other hints at isolating this interference?

If the ticking is very regular (like a clock), it's probably coming from
a digital device in his home or a close neighbor. First thing to do is
turn off the main circuit breaker in the house to remove power from all
possible sources for the ticking. Operate the radio on batteries and
listen for the tick. If it's gone, turn the main breaker back on. Now
turn off each circuit breaker in the box one at a time, to isolate which
circuit has the device which is making the ticking. When you find the
right circuit, start disconnecting all the devices on that line one at a
time. Eventually you'll track it down. I had a similar problem and
traced it to a cordless drill battery charger. It only made the sound
after the battery was fully charged.
If the noise didn't go away when the main breaker was off, take the
radio outside and walk around the neighborhood to see where the ticking
is strongest. You might have to question a neighbor or two after you
find the area where the ticking is loudest.