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Date: Thu, 13 Jan 2011 23:27:43 +0100
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: FET RDS
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Hi Minto,

Am 13.01.2011 23:09, schrieb Minto Witteveen:
> Stefan,
>
> You mentioned the IXDD414 in a previous message here on the reflector,=
=20
> and I immediately downloaded the datasheet. The IXDD414 certainly=20
> looks very promising and I plan to experiment with it as soon as we=20
> are allowed back on 500....=20
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=
=20
needed more. So i've ordered at digikey in USA. If you find a cheeper=20
distributor, please tell me (quantity below 10000000000000) :-)
> My original 500 KHz design was for linear operation (so I could use=20
> psk31) but I only made one qso in PSK, the rest in ordinary CW. A new=20
> design can and will be much simpler.
Have you heared about a class H modulator? This is a circuit that=20
separates AM and FM. The FM and PA can be done by a class E design and=20
the AM is applied by modulating the supply voltage by a step down=20
converter (the class H modulator). I've never built one but there are=20
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=20
mode. Since i do nothing more than CW/QRSS/DFCW i actually do not need=20
one ;-)

73, Stefan/DK7FC
>
> Thanks for the info.
>
> Regards,
> Minto pa3bca
>
>
> --------------------------------------------------
> From: "Stefan Sch=E4fer" <schaefer@iup.uni-heidelberg.de>
> Sent: Thursday, January 13, 2011 22:49
> To: <rsgb_lf_group@blacksheep.org>
> Subject: Re: LF: FET RDS
>
>> Minto,
>>
>> 14 nF gate capacity can easily be driven by a IXDD414, at 500 kHz and=
=20
>> even at 1800 kHz. I've built a 600W class E for 160m running at 36=20
>> VDC (for /p, 3 car batteries in series ;-) ), using 4xIRFP260N.=20
>> Efficiency is above 90% but mostly due to losses in the coils ( i=20
>> like to built it compact :-) ).
>>
>> 73, Stefan/DK7FC
>>
>
>