A pilot approaching Lodi; CA (103) was told that the airport's skydiver drop zone was always in use and so diverted to a nearby airport.

Narrative

I was PIC of a VFR flight to Lodi; CA (1O3). Prior to departure; I called Flight Service to obtain a NOTAM and TFR briefing for the route. I do not recall there being a NOTAM for skydiving in progress in Lodi. I was however aware that it does occur by looking through airport pubs; and the symbol on the sectional chart. I was aware that the drop zone is located on the southeast corner of the airport. Upon arriving in the Lodi area I called for an airport advisory on CTAF/UNICOM when I was 8 miles out. There was no response. Soon after; there was a Mooney reporting that he was on a straight in final to Runway 26. I wanted to look at the windsock if possible; but was still concerned about the drop zone. I elected to transition 2 miles north (estimated) of the airport to give clearance for the drop zone; just to be safe; although I did not believe it was being used because there were no position or drop reports from drop aircraft. Incidentally; I was never close enough to the airport to see the windsock clearly because of the offset. I announced that I was generally overhead the field for landing at 2100 FT. At this point; I was informed that there was a drop zone at the airport; and that it was active. I explained that I was actually transitioning north of the airport by a margin and was making a general position report. I asked that they advise when the drop was done as I did not want to land at the airport while a drop was in progress. The gentleman then responded that skydiving is always in progress in Lodi. I then elected not to land; because of the active drop zone; and the lack of traffic calls from jump aircraft in the area. I felt this was an unsafe situation; and diverted to Byron. I feel that proper use of the UNICOM/CTAF by jump operators to give advisories would be helpful. Also use of NOTAMs to alert landing and transiting aircraft of this hazard would be helpful. On my part; in the future; I will call a skydiving/glider operator that uses the airport beforehand on the telephone for information; as well as using the radio as a means of information gathering.