Help with distorted transmit audio
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Help with distorted transmit audio
 
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Today using SSB on 40M my K3 came up with pinched audio, the other operator
asked me to take the "clothes pin" off my nose. Full (and good) audio was obtained with a power cycle. I was told that signal strength came up significantly after the power cycle. I have posted this issue four times now. The problem doesn't surface everyday. I had thought my problem had something to do with HRD or use of the Elecraft K3 utility as in the past these had been used before the condition arose. But today I started the rig in the morning after a longish shutdown while I attended Pacificon. I did not use HRD or the download facility this morning so I no longer think that using those programs is involved with my this problem. The audio sounded like all highs in the monitor headset. The usual suspects have been looked at like the Tx equalizer and filter set up, that's what everyone has said to look at every time in the past. One and only one action is performed to bring the audio back to full and that is cycling power. I believe this fact rules out most set up issues. I suspect a firmware bug but it seems strange that I am the only target. Pinched audio could mean that the SSB signal isn't centered properly in the pass band of the 2.7 KHz Xtal filter, the rig is trying to transmit through the 500 Hz filter or the DSP is improperly initialized. Is there a relay contact that could be intermittent that could cause these symptoms, like one that switches in the 2.7 KHz filter? I have seen the same audio distortion using front and back microphone connectors and with two different microphones, one electret with bias the other dynamic without bias. Both microphone setups will get good audio reports after a power cycle. I run 13.8V from a 35 amp linear Astron power supply. Voltage drops to 13.1V with 100W key down so I don't think there is a marginal power supply condition. I have 13 KHz, 6 KHz, 2.7 KHz, and 500 Hz filters. SSB is only enabled on the 2.7 KHz filter. Mike Scott - AE6WA Tarzana, CA (DM04 / near LA) K3-100 #508/ KX1 #1311 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: Help with distorted transmit audio
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I experienced this pinched audio problem this weekend. Using the current beta firmware, I noted severely pinched transmit audio (using the transmit monitor). It occurred on some bands but not all, and was present sometimes on only one of the sidebands (i.e., when switching sidebands the audio pinching was gone, and returned when switched to the original sideband).
The problem disappeared upon reboot. Steve N9SZ
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Re: Help with distorted transmit audio
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In reply to this post by Mike Scott-7
I experienced this pinched audio problem this weekend. Using the current
beta firmware, I noted severely pinched transmit audio (using the transmit monitor). It occurred on some bands but not all, and was present sometimes on only one of the sidebands (i.e., when switching sidebands the audio pinching was gone, and returned when switched to the original sideband). The problem disappeared upon reboot. Steve N9SZ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: Help with distorted transmit audio
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In reply to this post by Mike Scott-7
>I experienced this pinched audio problem this
weekend. Using the current >beta firmware, I noted severely pinched transmit
audio (using the transmit >monitor). It occurred on some bands but not all, and
was present sometimes >on only one of the sidebands (i.e., when switching
sidebands the audio >pinching was gone, and returned when switched to the
original sideband). >The problem disappeared upon reboot. >Steve N9SZ Steve, I have had the same problem multiple times; I am glad to
hear someone else has the same problem. People I am talking to say to take the
clothespin off of my nose. In the transmit monitor I can hear thin audio. My
problem is that I don’t know how to replicate the distorted audio problem.
A power off reset fixes it every time when it shows up. I have been
experiencing this problem over many firmware downloads. I suspect there is a
root problem that is rare that stems back to the original firmware. I have
serial number 508 if that helps. I have engaged Elecraft help [Gary] but I am waiting for the
next instance of the problem. I don’t operate SSB very often so it may be
a while before it happens again. For the record Lyle asked that next time it
happens to change frequency or change transmit audio equalization to force a
new set up of transmit audio chain. Since I received these instructions nothing
has happened on my end so I am still waiting. The fact that you are changing bands and the problem stays
is an important input. Please keep reporting this issue and I will too when it
happens again. Mike Scott AE6WA Tarzana, CA K3/100 SN508 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: Help with distorted transmit audio
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Administrator
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In reply to this post by Mike Scott-7
Mike,
I tried hard to reproduce this -- no luck. Must be extremely rare. Were you using diversity mode and/or SPLIT? What crystal filter and DSP bandwidths were in effect? Which controls might you have been moving at the time? Thanks, Wayne N6KR --- http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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