On Wed, 2007-10-03 at 17:18 -0700, Kevin Purcell wrote:
> I know the "big design idea" between the Corsairs and the Paragons:
> conversion to 9MHz IF in the former and VHF (45MHz?) in the latter.
>
> But what are the differences between the successive models?
>
> What are the differences between Corsair Model 560 and Corsair II
I've never seen the schematics of the Corsair but I own a Corsair II
after studying the schematics. I believe the signal paths are
practically the same, though the II has a audio CW filter. The Corsair
has a band connector that the Corsair II doesn't. The front panel paint
is a different color, don't know about the dot on the logo. The Corairs
use a transformer fedback bipolar transistor for RF and first IF stages,
an Anzac patent but the most favored RF circuit according to Ulrich
Rohde's books. They use a diode ring mixer and the first IF stage
provides that broad band termination of the mixer. The RF attenuator
actually removes the RF stage from the circuit between the bandpass
filters and the mixer.
Omni V and VI don't use the Anzac circuit, but use 4 JFETs in parallel
in grounded gate which handles strong signals fairly well seems like
though I've not found numbers on it. Rohde liked a big TI JFET but its
been out of production a long time and 4 J310 may be a fair
approximation of it.
> Model 560?
>
> What are the differences between the Paragon and Paragon II?
>
> I'm interesting in the "hard(er) to see" changes: mixing schemes,
> radio/mixer design, gain distribution and the like.
>
> And opinions on usability and performance differences.
>
> This is a sort of follow on to the RX320/Jupiter "dual receive" thread.
>
> >> BTW, how does this differ from the Paragon and Paragon II?
> >>
> >
> > Only saw a Paragon schematic a few times, so I can't remember
> > the details too well. One big difference I do recall is that
> > the second IF is not at 455 like the 320/Pegasus/Jupiter/516
> > et. al. are.
> >
> > Duane
> > N9DG
>
> Thanks,
> --
> 73 DE N7WIM / G8UDP
> Kevin Purcell
> kevinpurcell@pobox.com
73, Jerry, K0CQ
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