Hello Alex
Congratulations for your work.
How much differ the bias for such low temp?
Keeping the die at -187F for a MRF157 device mean a
lower cooling temp for the transistor case than the -187F
specified for the die.
How do you deal with the heavy condensing water and ice?
To complete isolate (thermal) the amp module may be a solution,
but anyway, to isolate the entire amp (including the all N2 circuits)
seem no practical for an amp for home use.
And I should avoid touching a -250F object as much as for a HV circuit!
73,
Toate cele bune,
Traian, YO9FZS/p
alex wrote:
> I'll stick to my MRF157s :) Nothing beats them when coming to IMD at High
> power.
> I have a design cooling the devices with liquid N2 kipping the die at -187F.
> A pair puts out
> 2100W with -42dB IMD.
> But it took me 16months to get here :)
>
> Alex, N2NNU
>
> ----- Original Message -----
> From: "Tom Rauch" <w8ji@akorn.net>
> To: <amps@contesting.com>; "John T. M. Lyles" <jtml@lanl.gov>
> Sent: Tuesday, November 27, 2001 7:24 PM
> Subject: Re: [AMPS] new FETs
>
> >
> > > Advanced Power Technology in Oregon is coming out with the ARF1500
> > > series of high voltage RF power MOSFETS. Due 4Q01, these monsters are
> > > for class C -->E operation, with 1500 watt dissipation limit. There is
> > > one operating point for the 1501 suggested at 900 watts output, 300
> > > VDC Vdd, 17 dB gain, at 27 MHz. For linear class AB operation, they
> > > now have a 150 Volt part, the ARF 463, for 100 Watts CW up to 100 MHz.
> > > Whats neat about the APT parts is that they offer them in mirror image
> > > packages for P-P layouts.
> >
> > How is the IMD performance of the linear devices John?
> >
> > We have enough dirty tetrode amps on the bands, I wonder if the
> > IMD of these devices is state-of-the-art in IMD? I know the class C
> > designs weren't good enough.
> > 73, Tom W8JI
> > W8JI@contesting.com
> >
> > --
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> >
>
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