I have experienced this in the past as well on the original Kyphur WM6 versions. No current problems on Black 3.0.
Maybe you should try another WM6 release.
Don't think it is the radio ......... it is the link between WM6 and radio that seems to go into sleep mode.
Might be worthwhile to note what radio versions the developers are using.
Remember these Developers are not using our networks ... For that reason you are bound to run into these kinds of quirks ....
On another note .... have any of you guyz been experiencing dropped calls, try dialing a number and the call just ends ... data connections timing out/not connecting ....
over the past couple of months i used loadz of devices with more than one ROM on each of them ... i have had these hiccups but they seem to be cropping up more and more these dayz ...
For me its seems something fishy is going on wiff the networkx ...