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In a message dated 08/06/2004 08:22:21 GMT Standard Time, d.w.rollema@freeler.nl writes:

So it seems to me that class D and E amplifiers should preferably be followed by a low pass filter with a series inductor at the transmitter side.

Please correct me if my conclusion is not valid.

An interesting question is whether a low pass filter is really necessary when the transmitter feeds the aerial via a series tuning coil.

Hello Dick.

A brief response is that all the inductor input LPF circuits I have tried have either casused instability or fatal (for the FETS) voltages at the PA.

I did try your idea of no LPF in the early days of 73kHz, and managed to get a very nice 577 report from an amateur 2 miles away on 20m.

ooops

David G0MRF