Ahhhh bummer! Interference!
There is something in my area which generates interference across a large part of the VHF band, and sometimes up in UHF. Unfortunately there's not alot I can do about it. On stronger signals its not as noticeable, but some of the signals from the airport can be weak at times, especially when the weather is doing funny things.
I think it's just something we'll have to put up with, its very frustrating when I'm talking on the amateur bands!
Thanks for your feedback