From: G0MRF@aol.com
Message-ID: <6d33332c.24edec69@aol.com>
Date: Thu, 19 Aug 1999 19:25:29 EDT
Subject: Re: LF: high power class E transmitter
To: rsgb_lf_group@blacksheep.org
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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