using a scope on a k2
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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 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Are you looking to monitor your own key clicks or others'?
On Fri, Apr 8, 2011 at 3:06 PM, John Cooper <[hidden email]> 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 > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by John Cooper
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 > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Be careful if it's a K2/100. Probe ratings decrease with frequency, and the voltage
applied to the usual scope probe with 100w going into a 50-ohm load at 28 mHz will blow the 10x attenuator in probe. I don't need to tell you how I know this! On 4/8/2011 4:15 PM, Don Wilhelm wrote: > 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 Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Vic is right, scope probes have a peak voltage rating associated with
them. Violate those ratings at your own peril. 73, Don W3FPR On 4/8/2011 7:35 PM, Vic K2VCO wrote: > Be careful if it's a K2/100. Probe ratings decrease with frequency, and the voltage > applied to the usual scope probe with 100w going into a 50-ohm load at 28 mHz will blow > the 10x attenuator in probe. I don't need to tell you how I know this! > > On 4/8/2011 4:15 PM, Don Wilhelm wrote: >> 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 Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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