To check the quality of your radio go to Options/Status. The number will tell you how good a signal you are receiving. It is opposite of what you might think, as the lower the number the stronger the signal.
I didn't know this until I was having trouble with Vlingo timing out and they sent me the following reply:
"Vlingo works best with a strong network signal. Click BlackBerry Options -> Status. Ideally you want to see Signal somewhere between 0 and -100 dBm. The closer to 0, the better (though you’ll probably never see much lower than -80 or so – this would indicate a very strong signal). A value beyond -100 dBm indicates a weak signal and you may experience timeouts. Move to an area where you have a better signal."