Thanks jez

the CC1020 chip goes up to > 150kbit. But its new and these are not netto data rates. So after some checksum things this will drop to less than that.

Usually the range is much higher, so I might find a solution for short range that will achieve this. I have an idea to build the whole thing similair to a loosely coupled transformer. We successfully tested this principle in scuba diving equipment (air pressure is transmitted to the dive computer on the wrist). It works in salt water, but the data rate is only a couple of hundred bits per sec.

Werner