[TenTec] Orion 565 Key clicks (Karl Seper)

[Paul Christensen]

> I found it difficult to analyze the waveforms while trying to maintain
> sync - maybe a storage scope would have made things easier, but don't
> have access to one of those.

Here's a quick method to synchronize the monitored RF envelope on the scope 
to keep from having to chase the waveform:

Most transceivers and external keyers utilize a pull-up resistor to circuit 
Vcc at the paddle/key jack.  When the paddle, straight key or external keyer 
activates, the key line is grounded.  As such, a "Y" adapter can be used to 
sample this point to the scope's external trigger port or second scope 
channel when using a multi-trace scope.  The scope can be set to trigger 
upon a FALL of voltage sensed either at the external trigger port or scope 
input.  Precise waveform measurements can be made as well as measurement of 
propagation delay through the transmitter.  In other words, one can easily 
measure the time from "key down" to the onset RF just like that shown in the 
QST Product Reviews.  In addition to key click measurements, this gives a 
good idea as to potential QSK performance.

I take this concept a step further and have modified my external keyer with 
a positive going RCA jack.  So, as I send repeated keyed elements, each one 
can be seen on the scope.  On some transceivers, the first keyed element 
will behave differently than successive elements (e.g., ALC power spikes, 
"dit shortening," etc.).   Transceivers that are well-timed and have smart 
ALC systems show identical keying envelopes from the first keyed element in 
a series through the last.

Paul, W9AC