--- Kevin Purcell <kevinpurcell@pobox.com> wrote:
> What are the differences between Corsair Model 560 and
> Corsair II Model 560?
The Corsair (560) and the Corsair II (561) share the same
9-6-9 MHz IF mixing scheme. The active devices in the signal
paths look to be mostly the same. The 1st RX RF amps being
2N3866 in both models. Circuit board-wise the differences are
significant, at least in the RF/IF chain.
The Corsair uses a 1st mixer made from discrete MBD101's per
my schematic. The Corsair II uses a monolithic ring mixer
listed as a "87C2 K38", have no idea who the manufacturer of
that part is.
In the Corsair the 9 MHz filter lives on the NB board, in the
CII it is on its own board. The NB circuits are quite
different with the CII having some filtering ahead of the
noise detector. Don't see that for the Corsair.
The PBT board where the IF conversion to 6 MHz and back occur
look the same doing a quick perusal of the two schematics.
The IF/AF boards are quite different, mostly due to the
inclusion of a audio BP filter in the CII.
Some differences in the VFO/LO board designs but they don't
look too dramatic.
The TX specific RF boards, drivers, and PA's look mostly the
same, as do the RF bandpass and Lowpass filters. There are
several differences in the VOX and speech processing boards.
All these comparison done by doing a quick scan of the
various boards in the two schematics. No close study was
done. I need to sleep tonight ;).
When it's all said and done I could never tell any real
performance differences between the two Corsair variants
other than the stock 4 pole 1st IF filter in the Corsair
(with many having been upgrade to 8 pole like all CII's are).
Duane
N9DG
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