Message-ID: <001901beeb35$4f6892c0$3f4dedc1@default>
From: "Graham Phillips" <g3xtz@rgcomms.demon.co.uk>
To: rsgb_lf_group@blacksheep.org
References: <6d33332c.24edec69@aol.com>
Subject: Re: LF: high power class E transmitter
Date: Fri, 20 Aug 1999 18:56:13 +0100
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Hi David,

I am most interested in any info on the Harris DX25U ... is it am AM TX,
using Pulse-width modulation by any chance ?

Best wishes

de

Graham B. Phillips - G3XTZ.
g3xtz@rgcomms.demon.co.uk
----- Original Message -----
From: <G0MRF@aol.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: 20 August 1999 00:25
Subject: Re: LF: high power class E transmitter


> 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
>