Hello Rik and all.
I've recently been working (during my 9-5) on some medium wave transmitters.
For reference material I've been looking at the Harris DX25U which uses
IRFP350 power mosfets in class D with 230V DC to generate 25kW carrier and
100kW peak.
claimed efficiency for the PA alone is 92 - 97% with the whole TX operating
at 85%.
This seems to be the same as all the other class D circuits we're used to on
LF.
For interest:
The PA has 64 amplifier modules combined. 1 module = 1kW+
The combiner has multiple toroids threaded onto a large copper bar.
Modulation is 12 bit digital which then switches the drive to the modules on
/ off
PA circuits available if interested.
73
David
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