Hi Minto,
Am 13.01.2011 23:09, schrieb Minto Witteveen:
Stefan,
You mentioned the IXDD414 in a previous message here on the reflector,
and I immediately downloaded the datasheet. The IXDD414 certainly
looks very promising and I plan to experiment with it as soon as we
are allowed back on 500....
I've used them successfully up to 10 MHz, driving about 2 nF.
Now if I can just find a supplier here in PA who stocks this chip.
Yes, that's the problem. I've got 5 of them as a sample part but later i
needed more. So i've ordered at digikey in USA. If you find a cheeper
distributor, please tell me (quantity below 10000000000000) :-)
My original 500 KHz design was for linear operation (so I could use
psk31) but I only made one qso in PSK, the rest in ordinary CW. A new
design can and will be much simpler.
Have you heared about a class H modulator? This is a circuit that
separates AM and FM. The FM and PA can be done by a class E design and
the AM is applied by modulating the supply voltage by a step down
converter (the class H modulator). I've never built one but there are
some interesting examples at http://www.classeradio.com/classh.htm
This would be a good combination to push-up a class E PA for linear
mode. Since i do nothing more than CW/QRSS/DFCW i actually do not need
one ;-)
73, Stefan/DK7FC
Thanks for the info.
Regards,
Minto pa3bca
--------------------------------------------------
From: "Stefan Schäfer" <[email protected]>
Sent: Thursday, January 13, 2011 22:49
To: <[email protected]>
Subject: Re: LF: FET RDS
Minto,
14 nF gate capacity can easily be driven by a IXDD414, at 500 kHz and
even at 1800 kHz. I've built a 600W class E for 160m running at 36
VDC (for /p, 3 car batteries in series ;-) ), using 4xIRFP260N.
Efficiency is above 90% but mostly due to losses in the coils ( i
like to built it compact :-) ).
73, Stefan/DK7FC
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