Thanks to the joys of the internet, I now perform the time sync automatically
before each contest. Check out
http://www.bldrdoc.gov/timefreq/service/time-computer.html
You can download a program that automatically updates your computer clock.
Tom, K5RC
aka NV7A
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>From Marijan Miletic" <Marijan@Miletic.net Wed May 30 20:22:22 2001
From: Marijan Miletic" <Marijan@Miletic.net (Marijan Miletic)
Subject: [CQ-Contest] MP clicks
References: <200105291537.f4TFb8V10777@paris.akorn.net>
Message-ID: <007701c0e93f$e63f6660$2c48fea9@pentium>
----- Original Message -----
From: "Tom Rauch" <w8ji@contesting.com>
To: <cq-contest@contesting.com>; "Marijan Miletic" <Marijan@Miletic.net>
Sent: 29. maj 2001 15:35
Subject: Re: [CQ-Contest] MP clicks
>
> > Apart from frequency distance, we can always slow down the CW speed but
> > the opposite is often the case with PC contest code generation...
> >
> > 73 de Mario, S56A, N1YU
>
> Slowing the CW does not reduce the bandwidth in typical
> operation. Changing CW speed can change the spacing of
> sidebands and the number of clicks per second, but not the overall
> bandwidth of transmitter clicks.
>
Longer CW signal with short shaping will put considerably more energy into the
carrier as compared to the sidebands and we are using peak power limited
radios...
> Bandwidth is a function of waveshape and other issues (like a
> stable VCO frequency). Bandwidth (related to rise and fall times)
> can limit the maximum speed.
Shanon law is surely valid. Unstable VCO will mainly show up as a noisy
carrier.
> The 1995 Handbook, in section 12.12, goes into this in some detail
> on this. Look at the rise and fall times and maximum CW speed. I
> use about 7 mS in my rigs. What do you think you need?
> 73, Tom W8JI
> W8JI@contesting.com
>
My references come from the professional literature and work on DSP windowing.
7 ms is OK for very slow Morse code, 2 ms just about right for 20 ms contest
dots.
73 de Mario, S56A, N1YU
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