QSK THUMPS?
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When my K3 switches between T & R in full QSK mode, I hear audio thumps.
[The tramsmitted signal is apparently clean with no clicks; I always get good signal quality reports.] Now, My K2 has no such thumps; you can't tell when the radio switches between T & R by listening to the audio. The transmitted cw sidetone sounds just like any other cw signal, with no thumps or other noise. I would like my K3 to be the same. Is there anything I can do to attenuate the K3's audio thumps? eric VA7DZ K3 3620 + 500 W ICOM amp -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ______________________________________________________________ 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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I've heard this as well. Mostly when doing QSK with the Sub Receiver on, and even more so when in Diversity Mode. I think that it has to do with your Xmitted signal being heard by the receiver. Wayne had adjusted this at one time, but it seems to be an issue again. I find that if I turn on the NB it helps reduce it. > Date: Tue, 27 Apr 2010 17:07:06 -0700 > From: [hidden email] > To: [hidden email] > Subject: [Elecraft] QSK THUMPS? > > When my K3 switches between T & R in full QSK mode, I hear audio thumps. > [The tramsmitted signal is apparently clean with no clicks; I always get > good signal quality reports.] > > Now, My K2 has no such thumps; you can't tell when the radio switches > between T & R by listening to the audio. > The transmitted cw sidetone sounds just like any other cw signal, with > no thumps or other noise. > > I would like my K3 to be the same. > > Is there anything I can do to attenuate the K3's audio thumps? > > eric > VA7DZ > > K3 3620 + > 500 W ICOM amp > > > > > -- > This message has been scanned for viruses and > dangerous content by MailScanner, and is > believed to be clean. > > ______________________________________________________________ > 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 The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with Hotmail. Get busy. _________________________________________________________________ The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with Hotmail. http://www.windowslive.com/campaign/thenewbusy?tile=multicalendar&ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_5 ______________________________________________________________ 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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Thumps are often a symptom of RF ingress in the audio stage. Is the thump
effect reduced as the K3's transmit power is reduced? Paul, W9AC ----- Original Message ----- From: "The Smiths" <[hidden email]> To: "Elecraft Reflector" <[hidden email]> Sent: Tuesday, April 27, 2010 9:45 PM Subject: [Elecraft] FW: QSK THUMPS? > > > > I've heard this as well. Mostly when doing QSK with the Sub Receiver on, > and even more so when in Diversity Mode. I think that it has to do with > your Xmitted signal being heard by the receiver. Wayne had adjusted this > at one time, but it seems to be an issue again. > I find that if I turn on the NB it helps reduce it. > > > > > >> Date: Tue, 27 Apr 2010 17:07:06 -0700 >> From: [hidden email] >> To: [hidden email] >> Subject: [Elecraft] QSK THUMPS? >> >> When my K3 switches between T & R in full QSK mode, I hear audio thumps. >> [The tramsmitted signal is apparently clean with no clicks; I always get >> good signal quality reports.] >> >> Now, My K2 has no such thumps; you can't tell when the radio switches >> between T & R by listening to the audio. >> The transmitted cw sidetone sounds just like any other cw signal, with >> no thumps or other noise. >> >> I would like my K3 to be the same. >> >> Is there anything I can do to attenuate the K3's audio thumps? >> >> eric >> VA7DZ >> >> K3 3620 + >> 500 W ICOM amp >> >> >> >> >> -- >> This message has been scanned for viruses and >> dangerous content by MailScanner, and is >> believed to be clean. >> >> ______________________________________________________________ >> 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 > > > > > > > > The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with > Hotmail. Get busy. > > _________________________________________________________________ > The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with > Hotmail. > http://www.windowslive.com/campaign/thenewbusy?tile=multicalendar&ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_5 > ______________________________________________________________ > 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 -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.437 / Virus Database: 271.1.1/2839 - Release Date: 04/27/10 18:27:00 ______________________________________________________________ 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 Eric Manning
On Apr 27, 2010, at 8:07 PM, eric manning wrote: > Now, My K2 has no such thumps; you can't tell when the radio switches > between T & R by listening to the audio. > The transmitted cw sidetone sounds just like any other cw signal, with > no thumps or other noise. I'm curious -- what is the T-R setting on our K2 set to? If I set it to a high value -- say 150 (which I sometimes do when I'm using my non-QSK AL-80A amplifier), I don't get any thumps, but I wouldn't call it QSK by any means. If I set the T-R setting to something less than about 8, I can start to hear some anomalous stuff -- some minor thumps, and if I turn it down lower, I hear more. At settings below 2, you can even get some off-frequency receiver response. (ie you'll hear adjacent signals while keying, which stops the minute you stop keying) Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email] Web: http://boringhamradiopart.blogspot.com Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 ______________________________________________________________ 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 Eric Manning
Eric, a few things you might try:
Check whether you have NEW chosen in CW WGHT menu (p 54) Reduce RF gain Determine if the thumping changes if you decrease power and/or bypass the linear amp. Determine if it occurs when you operating SPLIT You might share your menu settings with the group. Someone sharper than I am may see the culprit. 73, Gary W7TEA
73,
Gary W7TEA K3 #1001, #5763 |
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In reply to this post by Eric Manning
I heard this too during a QSO not too long ago. It was intermittent tho and just started happening in the middle of the QSO. I was keying the rig through the USB->rs232 adapter with RUMLog's keyer at about 20wpm, I thought something had suddenly gone wrong. It did go away tho as the QSO went on...
I can't reproduce it with the build-in keyer plus paddles into a dummy load at any power setting. Perhaps I'll have another go with this with the computer and see what happens. Interesting.... 73, LS W5QD |
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You'll find that the louder the noise floor the worse the thumping. Again, reducing your RF gain, Turning on your NB and NR will help the thumping go away. It's possible that when you started hearing the problem the noise floor had risen up some, and then when it went away it had reduced again.. > Date: Wed, 28 Apr 2010 05:00:36 -0700 > From: [hidden email] > To: [hidden email] > Subject: Re: [Elecraft] QSK THUMPS? > > > I heard this too during a QSO not too long ago. It was intermittent tho and > just started happening in the middle of the QSO. I was keying the rig > through the USB->rs232 adapter with RUMLog's keyer at about 20wpm, I thought > something had suddenly gone wrong. It did go away tho as the QSO went on... > > I can't reproduce it with the build-in keyer plus paddles into a dummy load > at any power setting. Perhaps I'll have another go with this with the > computer and see what happens. > > Interesting.... > > 73, > LS > W5QD > -- > View this message in context: http://elecraft.365791.n2.nabble.com/QSK-THUMPS-tp4971836p4974029.html > Sent from the [K3] mailing list archive at Nabble.com. > ______________________________________________________________ > 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 _________________________________________________________________ The New Busy is not the too busy. Combine all your e-mail accounts with Hotmail. http://www.windowslive.com/campaign/thenewbusy?tile=multiaccount&ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_4 ______________________________________________________________ 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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One of the issues found in QSK operation is that TX-RX state changes
MUST modulated the received envelope. It is a fact that the RX stream must be turned off, and then turned on, to support transmitting and that is a modulation. The RX is ON after the latter state change and will hear the modulation. The only way to modify that modulation is by changing the shape and rise/fall times. This is the point at which the desire to hear between bauds, and to not hear artifacts of the state changes, are at odds with one another. A slower transition does less modulation, but slower can cause the transition to exceed the baud space, defeating the reason for QSK in the first place. To have clean hearing between bauds at 25 WPM does not allow time for soft and no-thump transitions. If there is anything being received, then the modulation of the RF envelope creates sidebands. The wider the energy being modulated, the greater likelihood of modulation sidebands. Set TX TEST, CW mode, QSK, then turn MON all the way down. Now hold down dits with your paddle and tune across a loud signal of any kind. Loud carrier between 7.2 and 7.3 is a good test. Most of my friends call that thumps, particularly if there is a really loud signal in the passband. This change is being imposed as far forward as the PRE/ATT. If you study the schematics, a lot of RF and 1st IF circuitry is either being switched out or reversed, thus imposing the modulation at points of mandatory artifact sideband generation. Having said that.... Now turn the RX EQ to -16 in bands 1 and 2 and note the large drop in the amplitude of the "thump". Also note (if you have the roofing filters for this) that the thumping is quite more pronounced with wide roofing filters than narrow. This is one instance where having headsets with hi fi response down to 15 Hz is no advantage. 73, Guy. On Wed, Apr 28, 2010 at 1:01 PM, The Smiths <[hidden email]> wrote: > > You'll find that the louder the noise floor the worse the thumping. Again, reducing your RF gain, Turning on your NB and NR will help the thumping go away. > > It's possible that when you started hearing the problem the noise floor had risen up some, and then when it went away it had reduced again.. > >> Date: Wed, 28 Apr 2010 05:00:36 -0700 >> From: [hidden email] >> To: [hidden email] >> Subject: Re: [Elecraft] QSK THUMPS? >> >> >> I heard this too during a QSO not too long ago. It was intermittent tho and >> just started happening in the middle of the QSO. I was keying the rig >> through the USB->rs232 adapter with RUMLog's keyer at about 20wpm, I thought >> something had suddenly gone wrong. It did go away tho as the QSO went on... >> >> I can't reproduce it with the build-in keyer plus paddles into a dummy load >> at any power setting. Perhaps I'll have another go with this with the >> computer and see what happens. >> >> Interesting.... >> >> 73, >> LS >> W5QD >> -- >> View this message in context: http://elecraft.365791.n2.nabble.com/QSK-THUMPS-tp4971836p4974029.html >> Sent from the [K3] mailing list archive at Nabble.com. >> ______________________________________________________________ >> 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 > > _________________________________________________________________ > The New Busy is not the too busy. Combine all your e-mail accounts with Hotmail. > http://www.windowslive.com/campaign/thenewbusy?tile=multiaccount&ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_4 > ______________________________________________________________ > 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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