> with the comment "with clicks." I am using my Orion II (version
> 2.037j) and was running close to the legal power limit (Alpha 99)
> with a separate receiving antenna so that I do not have to exercise
> the A99's relays.
Bill,
The best way to measure rise/fall time on a scope is to externally trigger
the scope's input. This generally requires a separate contact closure or
open-collector. Also, most scopes will trigger on either the leading or
trailing edge of a waveform, but in either case, a positive voltage is used
to externally-trigger the scope. In my case, I modified a microHam CW keyer
by adding a new open collector output in series with a 1 K resistor to the
power supply rail for isolation. Now, the keyer provides the necessary
closure to key the rig and a separate and isolated output triggers the
scope. I can leave the time base set for 5 or 10 ms/div. and not fight with
chasing the waveform to stabilize it on the screen.
Back to your issue -- the occupied bandwidth of the CW waveform is primarily
a function of the shape of the rise/fall time. Rise/fall times over 4 ms or
so are pretty much limited by the shape of the keyed waveform and not the
time it takes to go from zero to full output power. I suspect that the
operator on the other end was hearing your station well above S9, or perhaps
his noise blanker was left on. Even with well-shaped waveforms, there's
going to be some resulting bandwidth that will be heard as clicks if the
received signal strength is high. Of course, the use of a noise blanker can
also create the illusion of severe clicking.
One last issue might relate to the keying of the Alpha 99 amp. Make sure
you sample the RF after the amp as well as in front of the amp when making
these tests. This will give you a clue as to whether or not the amp is hot
switching. I would think that the Orion connection into the 99 should be
pretty safe, but then I've seen these interfaces fail before. Hot switching
creates the worst form of key click since the rise or fall time of the hot
switching point is near zero.
Paul, W9AC
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