[MacLoggerContest] Fun with theology

Bill Coleman aa4lr at arrl.net
Wed Mar 16 16:17:06 EST 2005


On Mar 14, 2005, at 7:29 AM, Don Agro wrote:

> Hi Chuck, Bill,

> MacLoggerDX does in fact pause 2 dit intervals between characters PLUS 
> 4 dit intervals between words resulting in a total of 6 dit intervals.

There are several programs in the PC world that use a "short" space. 
For example, CQPWin (yeah, I know) allows you to insert a "*" instead 
of a space character. I don't know how many dit intervals this is 
precisely, but it does result in faster sending.

2 dit intervals between characters seems somewhat too short to me.

> The people who tested this found it perfectly copyable.
>
> This tangent arose because of the (incorrect I feel) assertion that 
> accurately timed CW could not be generated in software on a Mac.

If nothing else, the ancient Sound Manager is capable of generating 
very precise timings down to less than a millisecond. MacOS X has more 
modern (and more accurate) replacements.

> I was merely using K3MT's reference to show the approximate operating 
> system granularity required to generate accurate CW at 32 WPM.
>
> Now if I base my calculations on an average word size of 48 dit spaces 
> and someone else says that the average word size is 50 dit spaces it 
> really doesn't matter - except that our words per minute may vary by 
> around 4% - but the relationship between MacLoggerDX's dits, dahs and 
> spaces is still fixed at an accurate and copyable ratio timed to the 
> fraction of a millisecond.

For all those generating CW on the serial port RTS line -- I wonder how 
much fixed and variable latency there is on these USB / serial 
adapters. I suppose it would depend on the other activity on the USB 
port as well, since USB, unlike Firewire, doesn't have a guaranteed 
level of service.

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901



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