Missed calls. Please help with your 2 cents.

[mikenerd]

Trying to figure out the solution to this:

I seem to miss about 1 call per week (1 in 30 calls) on my TP (Sprint) in my house. There is no ring just my voicemail indicator coming on. I get the voicemail indicator within seconds of the caller leaving it. I don't feel like I ever look at my phone and see that I am out of range but the number of bars does fluxtuates quite a bit. Also, I have never dropped a call in my house. I have tried setting to automatic and sprint only and increasing my polling interval without any change. I called Sprint and they say all the towers are working in the area. Does this sound like a radio or network issue? Should I try flashing to a different radio? I have not flashed a radio before but have read the main TP radio thread. Any advice would help. Thanks