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
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