K2 Transmit audio bubbly
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Hello,
Until today I have had no audio problems but this noon while I was in QSO I was told that my audio was clipping and progressively worsening. This was confirmed by another ham on freq. I monitored my signal with another radio and my voice audio understandable but sounds rather bubbly or bumpy as if I were operating mobile on a washboard road. ALC is now showing 1-7 LED's lit with SSBA 2 & SSBC 2-1. As I recall, when built, the ALC had no more than 2-3 LED's lit. No change with substituted mics. No change whether powered with battery or power supply. Distortion is present on all bands and at all power settings... from .1 to 100 watts. Distortion is present even if I am soft talking with 1 LED lit on ALC. My only change this past week has been the addition of a KAT100 and I have had several QSO's since without problems reported before this occurred. The assembly, alignment, testing, etc. of the KAT100 went very well. Is there a known problem I need to address? Do I need to reset the K2 configuration to factory defaults? Help is appreciated... thanks. Ed - AD7GR K2/100 #6050 _______________________________________________ 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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Ed,
I suggest for your first step that you remove the right side panel from the K2 and tuck the ribbon cable and speaker wire up into the area near the top of the control board. If those cables are run over the KSB2 board it can often cause symptoms about like you describe. Unless you have an 'RF in the shack' condition that creates mic feedback, I can't think of anything that would be caused by the addition of the KAT100 - except for the additional data traffic on the ribbon cable to the KPA100 needed to talk with the KAT100, and dressing that cable will help if that is the cause. One other thing that you could do is to ground the shell of your mic jack and be certain the mic cable has a shield connection to the shell of the mic plug. If you still have problems, test for RF in the shack by connecting a quarter wavelength wire to the ground lug on the KAT100 (leave the far end open, insulated and in the clear, just as you would an antenna end, there will be high voltage RF on it). If the counterpoise wire makes a difference, you need to look at your antenna system to see how the RF in the shack can be reduced (baluns, feedline chokes, better antenna balance, etc.). Do NOT reset the K2 unless you have recorded all your menu settings including the filter and BFO settings. A master reset is not likely to help any with a problem like you have, but it certainly can mess things up and you will be in for a CAL PLL and filter alignment job and restoration of other settings if you choose to do that reset. 73, Don W3FPR eKotz wrote: > Hello, > > Until today I have had no audio problems but this noon while I was in > QSO I was told that my audio was clipping and progressively > worsening. This was confirmed by another ham on freq. I monitored > my signal with another radio and my voice audio understandable but > sounds rather bubbly or bumpy as if I were operating mobile on a > washboard road. > > ALC is now showing 1-7 LED's lit with SSBA 2 & SSBC 2-1. As I > recall, when built, the ALC had no more than 2-3 LED's lit. > No change with substituted mics. > No change whether powered with battery or power supply. > Distortion is present on all bands and at all power settings... from > .1 to 100 watts. > Distortion is present even if I am soft talking with 1 LED lit on ALC. > > My only change this past week has been the addition of a KAT100 and I > have had several QSO's since without problems reported before this > occurred. The assembly, alignment, testing, etc. of the KAT100 went > very well. > > > Is there a known problem I need to address? Do I need to reset the > K2 configuration to factory defaults? > 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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Don Wilhelm wrote:
> Unless you have an 'RF in the shack' condition that creates mic > feedback, I can't think of anything that would be caused by the addition > of the KAT100 - except for the additional data traffic on the ribbon > cable to the KPA100 needed to talk with the KAT100, and dressing that > cable will help if that is the cause. There have been problems with KPA100 oscillation that was triggered by particular reactance/resistance combinations seen by the amplifier; and this may be created by adding a KAT100 (or using a particular feedline length). I experienced this myself. The latest KPA100 mods are supposed to have addressed this problem, so it is worth verifying that you have them installed. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ 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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In reply to this post by eKotz
Is your KAT100 grounded - I had a barrow load of problems when I forgot to
do this 73 Barry GM4TOE Barry Horning .....Box and Clock maker A'anside Studios www.aanside.co.uk www.scottish-gifts-online.co.uk -----Original Message----- From: eKotz [mailto:[hidden email]] Sent: 15 September 2007 23:30 To: [hidden email] Subject: [Elecraft] K2 Transmit audio bubbly Hello, Until today I have had no audio problems but this noon while I was in QSO I was told that my audio was clipping and progressively worsening. This was confirmed by another ham on freq. I monitored my signal with another radio and my voice audio understandable but sounds rather bubbly or bumpy as if I were operating mobile on a washboard road. ALC is now showing 1-7 LED's lit with SSBA 2 & SSBC 2-1. As I recall, when built, the ALC had no more than 2-3 LED's lit. No change with substituted mics. No change whether powered with battery or power supply. Distortion is present on all bands and at all power settings... from .1 to 100 watts. Distortion is present even if I am soft talking with 1 LED lit on ALC. My only change this past week has been the addition of a KAT100 and I have had several QSO's since without problems reported before this occurred. The assembly, alignment, testing, etc. of the KAT100 went very well. Is there a known problem I need to address? Do I need to reset the K2 configuration to factory defaults? Help is appreciated... thanks. Ed - AD7GR K2/100 #6050 _______________________________________________ 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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In reply to this post by Don Wilhelm-4
Don't forget the magnetic field susceptibility.
Move the rig away from the big ole power supply transformer. Dan / WG4S / K2 #2456 <snip> sounds rather bubbly or bumpy as if I were operating mobile on a washboard road. </snip> _______________________________________________ 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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