I have noticed the same thing.  It seems to be almost perfect in the 
early morning, but really struggles in the afternoon, even though it 
is the same route, only in reverse.  I noticed that Andre, i believe 
it was, had a lot of trouble getting it to work well last summer in 
las Vegas at the ACB convention, when temps were over 100 degrees.
Andy
At 05:50 AM 6/7/2006, you wrote:
>Hi everyone, I have had my Trekker GPS for a few months  wont, and have
>  made a few observations.  When it is hotter out it takes it longer to get
>a signal, and when it does it seems that the signal isn't that good.  i
>went out on Sunday when it was cooler and it worked better, but this week
>when it has been warmer the signal strength hasn't been too hot.