I live in LA where there's poor reception everywhere, and I just discovered how to get better reception from my iTrip (w/ my 4G iPod). Just plug in either the Firewire or USB cable to the iPod dock connector.

I'm guessing the cable shares a common ground with the iPod & iTrip, forming a longer transmit antenna - but who cares why - the fact is that it works. And the cable doesn't have to be plugged into a power source (like the PowerPod) on the other end (although this is how I use it).