Noise on received audio
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I have K2 s/n 4426 and have been using it for over 1 yr. I built it
orginally as the qrp radio with all options except the KIO2. I have also built the K2/100 options and use this only at the home qth and take the battery qrp configuration on travel. I have recently started noticing distorted or "buzzing" riding on type of the audio. This is most audible on CW with strong signals, but I can also her it on SSB voice signals as well. It almost sounds like the person I'm listening to has rf on THEIR signal, though I know this is not the case as EVERY signal has this noise. I hear it most pronounced when using the 100W amp lid, but I can also hear it when using the qrp lid. Here is perhaps a clue to the source....when I lift up the front of the lid on either the 100W lid or qrp lid about 2" high, the noise goes away completely. In fact, if I tilt up the front of the lid, and stick the handle of my screwdriver underneath it to hold it up, the audio is perfect...Could something on the motherboard of the K2 be generating just enough noise to get picked up by the audio sections/speaker wires in the lids of my rig? Rig has SSB, DSP options installed. The noise comes through whether I'm using an external speaker or headphones, it doesn't matter. I do not have a scope to do any snooping, but any ideas that could help me eliminate this noise thru trial and error would be appreciated. The radio is still usable, but this is somewhat irritating and frustrating... Thx 73 K5GUS _______________________________________________ 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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Dan Schieler wrote:
> I have recently started > noticing distorted or "buzzing" riding on type of the audio. This is > most audible on CW with strong signals, but I can also her it on SSB > voice signals as well. <snip> > I hear it most pronounced when using the 100W > amp lid, but I can also hear it when using the qrp lid. This could be a long shot, but maybe it's the old 'magnetic field pickup' problem. When I first added the KPA100 to my K2, I noticed that the sensitivity to AC magnetic fields increased. Who knows why! I had originally had a problem from my antenna rotor control box with the QRP K2, so I moved it. When I got the 100w lid, I had to move it again. So, how far is your K2 from a linear power supply, rotor control, or anything with a transformer or motor in it? Elecraft has a mod (named after me, K2VCOSHLDKT) that will greatly reduce sensitivity to such fields, but if you haven't installed this mod then you should keep all such magnetic sources at least 18" away from the K2. -- 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 Dan Schieler
Vic, thanks! You nailed it. I recently moved the K2 while 'tidying up' the cables behind the desk and moved the radio on a shelf just above my Alino DM340V linear supply.....moved the rig back to its original spot and the noise was gone....just in time for an evening with the ww cw contest! Fyi, the k2 is now side by side with an Alinco switching supply but it doesn't seem to mind....the other supply has a big honkin tfrmer in it.... Thx again! K5gus... -----Original Message----- From: "Vic K2VCO" <[hidden email]> Subj: Re: [Elecraft] Noise on received audio Date: Sat Nov 26, 2005 2:34 pm Size: 1K To: "Dan Schieler" <[hidden email]> cc: "[hidden email]" <[hidden email]> Dan Schieler wrote: > I have recently started > noticing distorted or "buzzing" riding on type of the audio. This is > most audible on CW with strong signals, but I can also her it on SSB > voice signals as well. <snip> > I hear it most pronounced when using the 100W > amp lid, but I can also hear it when using the qrp lid. This could be a long shot, but maybe it's the old 'magnetic field pickup' problem. When I first added the KPA100 to my K2, I noticed that the sensitivity to AC magnetic fields increased. Who knows why! I had originally had a problem from my antenna rotor control box with the QRP K2, so I moved it. When I got the 100w lid, I had to move it again. So, how far is your K2 from a linear power supply, rotor control, or anything with a transformer or motor in it? Elecraft has a mod (named after me, K2VCOSHLDKT) that will greatly reduce sensitivity to such fields, but if you haven't installed this mod then you should keep all such magnetic sources at least 18" away from the K2. -- 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 Dan Schieler
oh yeah....and I need to get that mod done that you mentioned....anyone know if its standard now or if it would have been part of sn 4426?
-----Original Message----- From: "Vic K2VCO" <[hidden email]> Subj: Re: [Elecraft] Noise on received audio Date: Sat Nov 26, 2005 2:34 pm Size: 1K To: "Dan Schieler" <[hidden email]> cc: "[hidden email]" <[hidden email]> Dan Schieler wrote: > I have recently started > noticing distorted or "buzzing" riding on type of the audio. This is > most audible on CW with strong signals, but I can also her it on SSB > voice signals as well. <snip> > I hear it most pronounced when using the 100W > amp lid, but I can also hear it when using the qrp lid. This could be a long shot, but maybe it's the old 'magnetic field pickup' problem. When I first added the KPA100 to my K2, I noticed that the sensitivity to AC magnetic fields increased. Who knows why! I had originally had a problem from my antenna rotor control box with the QRP K2, so I moved it. When I got the 100w lid, I had to move it again. So, how far is your K2 from a linear power supply, rotor control, or anything with a transformer or motor in it? Elecraft has a mod (named after me, K2VCOSHLDKT) that will greatly reduce sensitivity to such fields, but if you haven't installed this mod then you should keep all such magnetic sources at least 18" away from the K2. -- 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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> oh yeah....and I need to get that mod done that you mentioned....anyone know if its standard now or if it would have been part of sn 4426?
It isn't and it wasn't :-) 73, Lyle KK7P _______________________________________________ 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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