Subject: Why does my walkman reception change on the bus?

I ride the bus to school, and for the trip I bring along my radio walkman to 
listen to the radio.  This walkman is a simple, sony walkman that I bought at 
least 8 years ago.  For the past 3 months I have noticed an annoying trend.  
When I'm riding the bus the reception for a station is relatively clear, but 
almost everytimg the bus stops to unload or load more passengers, the reception 
immediately goes all fuzzy.  When the bus starts moving again the reception 
returns to its previous clarity.  This really bugs me, and what bugs me more is 
I do not know how to explain why this happens!   Could you somehow enlighten 
me?  Many thanks!

Re: Why does my walkman reception change on the bus?