General aviation pilot on IFR flight plan reports interference on SAV approach frequency 125.3 with RDU departure. RDU is very loud requiring SAV to repeat instructions.

Narrative

I was IFR though weather was VMC; approaching Statesboro Airport (TBR) from the north; descending from 8;000 FT to 5;000 FT then later to 2;000 FT MSL. When switched to Savannah; GA; Approach on 125.3; I noticed that while I could communicate with Savannah; I could also hear Raleigh; NC; Approach on the same frequency. A few times while Savannah was transmitting an ATC instruction; the Raleigh TRACON would also begin transmitting simultaneously; thus 'blocking' or 'stepping on' the Savannah instruction. This occurred repeatedly while approaching TBR. Perhaps the severity of this effect is dependent on altitude; radio type; weather; and/or other factors. However; in my opinion; the frequency 125.3 should not be used by both Savannah and Raleigh; since they are apparently close enough geographically for some aircraft controlled by Savannah to receive Raleigh. This issue; if unresolved; could result in missed or garbled communication with ATC. Callback conversation with Reporter revealed the following information: This was the first time the reporter had been to this area and the first time the interference encountered. He has not been back and cannot state if this is a common occurrence.