-----Original Message-----
From: K4RO Kirk Pickering <k4ro@k4ro.net>
To: trlog@contesting.com <trlog@contesting.com>
Date: Wednesday, July 29, 1998 3:24 AM
Subject: [TRLog] Optocoupler switching time?
>
>For those of you using optocouplers in your radio keying lines,
>have you noticed that the speed of the device makes any difference?
>
>The optocouplers I've come across are 5 microsecond switching time.
>I now understand that there are faster ones out there (2 uS.)
>Has anyone noticed if the switching speed makes any real difference?
At 30 wpm, a dit lasts about 43 milliseconds; 43,000 uS!!
What difference will a 5 uS switch speed make? Your rig cannot
respond to anything going on that fast; in fact, the bandwidth
to pass a 5 uS pulse is wider that any CW rig pass band.
Don't worry about the switching speed in uS! Even at
60 wpm, you are still thousands of uS longer than the
switch time. Your headphones will do nothing even if
a 5 uS pulse of current were to "try" to pass through
your audio circuit.
73, Jim, KH7M
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