GPS Interferes With AM Radio Reception

[JimMeade]

When I turn the Ag Leader Integra GPS system on, it interferes with the AM radio receiver.  The interference goes away when the GPS is off.  

Does anyone have any similar experience?  Do you know a solution?  Has anyone tried an RF choke, and if so, what were the results and what were the characteristics of the choke?

TIA

[JimMeade]

The GPS antenna lead was too close to the AM receive antenna.  When I moved it the problem went away.