Re: using a scope on a k2

Posted by Don Wilhelm-4 on Apr 08, 2011; 11:15pm
URL: http://elecraft.85.s1.nabble.com/using-a-scope-on-a-k2-tp6254907p6255620.html

  John,

I have to condition my answer on this one because I do not know what
kind of  'scope you have available.

If it has a sufficiently high frequency response (3 times the frequency
of the RF to be measured), and it has a 10X probe with it, then the
procedure is easy - just connect the 10X probe across your dummy load.
If your dummy load does not have easy access to connect the 'scope
probe, use a Tee adapter at the dummy load end to gain access to the
center conductor.

If you do not have a modern 'scope with adequate frequency response,
contact me off-list and I may be able to dredge some old information out
to enable you to do the same thing - it is somewhere in my ole references.

CW:
Set the sweep rate to something slow matching your keying rate (key the
TX with a string of dots), and observe the RF waveform.  If it has sharp
transitions, that is an indicator of potential keyclicks.  Look at the
'scope traces shown in the Elecraft K2 Keying Waveform Mod instructions
for an example of what to look for.

For SSB:
Set up about the same as for CW (the sweep rate will be at an audio
rate).  You will have to review some of the waveforms in the ARRL
Handbook to see what clipping looks like before being able to judge the
waveforms.  For amplitude, compare the peak of the audio wave to what is
obtained in CW mode - and that level will represent your PEP.

Note that you will not actually be able to observe splatter with the
'scope, that takes a Spectrum Analyzer - if the waveform shows clipping
(abrupt transitions at the peaks), that is an indicator that splatter is
occurring, but the 'scope will not show it directly.

73,
Don W3FPR

On 4/8/2011 3:06 PM, John Cooper wrote:
> How would I use a scope to monitor key clicks on cw, and the waveform on ssb?  Also anything else I can do with a scope too?  This is in reference to a K2  IE where do the probes go and so forth.  Off list is fine too.  Couldn’t find any definitive answer in the archives.
>
>
> WT5Y
>
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