On Nov 12, 2005, at 10:50 AM, Karsten Eppert(DK4AS) wrote:
I am in doubt about the optimum CW-pitch. I think I remember from
the old days, that the human ear has the best "built in" filter
around 1000 Hz, so I thought, CW-crystal filters should have a
pitch around 1000 Hz. Many commercial units seem to have 800 Hz,
the standard K2 has a suggested pitch of 600 Hz.
While a lot of older rigs had an offset for 1000 Hz, most newer rigs
are 700-800 Hz. But long-time CW ops typically go for even lower
signals, sometimes in the range of 400 Hz.
1. why is that so?
600 Hz is a good compromise between a lower frequency and single-
signal reception. Much lower, and you're going to hear signals on the
opposite side of the zero-beat.
2. I have set my K2 to 700 Hz but live with the very personal (not
supported by spectrogram) impression that the overall selectivity-
response is broader than it could be.
The adjustable filter has a narrow response, but it's skirts aren't
that steep.
Is it possible, that the NF-path is optimised for a 600 Hz-
response? If so, I would go through the entire re-alignement
procedure and reset everything to 600 Hz. Or is it all stupid
personal impression?
The response would be equally as broad at 600 Hz as at 700 Hz. I'd
leave it.
Bill Coleman, AA4LR, PP-ASEL Mail: [EMAIL PROTECTED]
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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