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From: "Dick" <knaap159@zonnet.nl>
To: <rsgb_lf_group@blacksheep.org>
Date: Mon, 27 Mar 2006 12:14:29 +0200
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Subject: LF: G0MRF/G3YXM TX-mix
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Status: O

Hello,

I'm planning to built a bit stronger station for 136kHz to take with me to
LX later this year.

I already have a 300W TX, design G0MRF with 2 FET's.

I came across the design of G3YXM with 4 times IRFP450, however as I do not
have the
Hall-device used in its protective circuit, so I had to figure out something
else.

By the way: did somebody noted a diverence between IR or 'Harris' FET's??

The new plan is to built the original G0MRF system, and replace the original
2 FET's by
4 times IRFP450 using the values/components according to the G3YXM design,
including the 'zobel-network' .
The current and SWR protection will be the same as in the G0MRF set up.
This protection proved to be very fast and efficient in my excisting TX.

There is a difference in the way the TX is keyed.

G0MRF is keying the TC4426 FET driver, while G3YXM is keying the supply line
towards the
4 power FET's.

I'm wondering what the practical difference is between these 2 ways of
keying.

73

Dick, PA4VHF