> or two. Ten Tec would know better than I what that time is. It is
> the time in which the ALC circuit timing resets after sending
> elements. I believe this explains the different rise time and the
Sure appears that way.
> The rise and fall times of 3mS seem to be a good compromise too.
> Short enough to create distinct elements to cut through QRN and QRM
> but long enough to minimize key clicks, hence being a good
Actually that is still about half the rise and fall time needed.
I don't know where the rumor comes from that excessive bandwidth
somehow results in "cutting QRM or QRN" better. It certainly is not
based on any type of engineering or research!
The CCIR and others spent a lot of time looking into this and
decided filtered dots with a 5mS rise and fall were ideal at speeds
faster than most of us use in clear channel operation, and faster
than ALL of us use when signal are marginal. Cutting the
recommended time nearly in half nearly doubles required
bandwidth, while doing nothing to improve readability.
If we are going to use shorter rise and fall times than needed, we
either better be prepared to stay several hundred Hz away from
others and to use better filtering than a simple R/C filter for shaping
in the CW transmitter.
73, Tom W8JI