K3: KPA100 Squeal
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That's the first place you should have asked. Contact k3support at elecraft.com or gary at elecraft.com and you will make much faster progress to a resolution. 73, Bill |
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In reply to this post by AB3LS
gosh if everyone did that then we wouldnt have the endless strings
"when i shout into my K3 mike my neighbors lights flicker. Am I using the wrong mie and what mike should I use" HAR Bob K3DJC On Fri, 1 Jul 2011 03:38:26 -0700 (PDT) Bill W4ZV <[hidden email]> writes: > > AB3LS wrote: > > > > Anyone from Elecraft have anything on this? > > > > That's the first place you should have asked. Contact k3support at > elecraft.com or gary at elecraft.com and you will make much faster > progress > to a resolution. > > 73, Bill > > > -- > View this message in context: > tml > Sent from the Elecraft 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 > > ____________________________________________________________ 57 Year Old Mom Looks 27! Mom Reveals $5 Wrinkle Trick That Has Angered Doctors! http://thirdpartyoffers.juno.com/TGL3141/4e0de4fbe32667a47m03vuc ______________________________________________________________ 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 AB3LS
You get this while in TX mode?
Do you have the top cover on or off for this? Guy On Fri, Jul 1, 2011 at 1:49 AM, Geoff Wolf AB3LS <[hidden email]> wrote: > No go. > > Hooked the radio up to a gel cel battery and we're still getting the 12Khz > junk coming from something and the clicking between TX and RX. > > I made a longer recording of the 'junk' and posted it. Cycled between TX and > RX a few times using the manual TX button on the front. Then finished off > with a few dits and dahs. All while in TX Test mode. > > http://alien.liltechdude.com/files/index.php?dir=Recordings/&file=kpa3squealrev2.mp3 > > Anyone from Elecraft have anything on this? > > AB3LS > > On Fri, Jul 1, 2011 at 1:24 AM, Geoff Wolf AB3LS <[hidden email]>wrote: > >> This is a brand new K3 that I assembled about a month ago. The Serial >> Number is 5517. >> >> I have been using an Astron SS-25A power supply with this which is indeed a >> switcher. I have a battery that I'll be hooking up to it to see if this is >> still a problem. >> >> >> On Thu, Jun 30, 2011 at 4:41 PM, Guy Olinger K2AV <[hidden email]>wrote: >> >>> A repeated 12 kHz would be echoed all over the room and lose a lot of >>> it's pulse nature. This continues to look suspiciously like crap from >>> a 12 volt switching power supply that is somehow finding something >>> mechanically resonant in the K3. >>> >>> Back to asking for 12 volts from a linear supply (transformer and 60 >>> Hz rectifiers) or battery. >>> >>> Is this particular K3 serial # prior to the introduction of gold >>> plated pins for the KPAIO3 connection? >>> >>> 73, Guy. >>> >>> On Thu, Jun 30, 2011 at 1:52 PM, W5UXH <[hidden email]> wrote: >>> > I looked at the MP3 file using Goldwave. It appears to me that the "12 >>> KHz" >>> > component is present only during the tics, not continuously. >>> > >>> > The tic period is roughly 270 msec (I have no idea what the tic is of >>> > course). I zoomed in to a single tic (see PDF of images at the link >>> > below). It appears that each tic has a very distinct pattern seen in >>> the >>> > individual samples which I suspect is the 12 KHz energy. >>> > >>> > I have no idea what any of this means. >>> > >>> > 73, >>> > >>> > Chuck, W5UXH >>> > Las Cruces, NM >>> > >>> > >>> https://sites.google.com/site/k3lineoutrecordings/ab3ls-mp3-file-analysis >>> > Images and comments from Goldwave view of the MP3 file >>> > >>> > >>> > Guy, K2AV wrote: >>> >> >>> >> Hi Geoff, below... >>> >> >>> >> On Thu, Jun 30, 2011 at 9:24 AM, Geoff Wolf AB3LS >>> >> <[hidden email]> wrote: >>> >>> And, for even more information, I analyzed the audio that I recorded >>> and >>> >>> the >>> >>> squeal is right around 12Khz. It peaks at -48dB (louder than the QSK >>> >>> relay >>> >>> clicking) >>> >>> >>> >>> http://imgur.com/V8o5t - image of the analysis >>> >>> >>> >>> AB3LS >>> >> >>> >> With your image I realize I had been making some assumptions. I need >>> >> to fill in some details... >>> >> >>> >> Are you listening to the audio in earphones or are you hearing it in >>> >> the free air. I had been assuming listening with your ears only in >>> >> free air to miscellaneous sound in the neighborhood of the K3. >>> >> >>> > >>> > >>> > -- >>> > View this message in context: >>> http://elecraft.365791.n2.nabble.com/K3-KPA100-Squeal-tp6518460p6534295.html >>> > Sent from the Elecraft 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 >>> > >>> ______________________________________________________________ >>> 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 > 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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That would be: You get this while in TX Test Mode?
On Fri, Jul 1, 2011 at 12:17 PM, Guy Olinger K2AV <[hidden email]> wrote: > You get this while in TX mode? > > Do you have the top cover on or off for this? > > Guy > > On Fri, Jul 1, 2011 at 1:49 AM, Geoff Wolf AB3LS > <[hidden email]> wrote: >> No go. >> >> Hooked the radio up to a gel cel battery and we're still getting the 12Khz >> junk coming from something and the clicking between TX and RX. >> >> I made a longer recording of the 'junk' and posted it. Cycled between TX and >> RX a few times using the manual TX button on the front. Then finished off >> with a few dits and dahs. All while in TX Test mode. >> >> http://alien.liltechdude.com/files/index.php?dir=Recordings/&file=kpa3squealrev2.mp3 >> >> Anyone from Elecraft have anything on this? >> >> AB3LS >> >> On Fri, Jul 1, 2011 at 1:24 AM, Geoff Wolf AB3LS <[hidden email]>wrote: >> >>> This is a brand new K3 that I assembled about a month ago. The Serial >>> Number is 5517. >>> >>> I have been using an Astron SS-25A power supply with this which is indeed a >>> switcher. I have a battery that I'll be hooking up to it to see if this is >>> still a problem. >>> >>> >>> On Thu, Jun 30, 2011 at 4:41 PM, Guy Olinger K2AV <[hidden email]>wrote: >>> >>>> A repeated 12 kHz would be echoed all over the room and lose a lot of >>>> it's pulse nature. This continues to look suspiciously like crap from >>>> a 12 volt switching power supply that is somehow finding something >>>> mechanically resonant in the K3. >>>> >>>> Back to asking for 12 volts from a linear supply (transformer and 60 >>>> Hz rectifiers) or battery. >>>> >>>> Is this particular K3 serial # prior to the introduction of gold >>>> plated pins for the KPAIO3 connection? >>>> >>>> 73, Guy. >>>> >>>> On Thu, Jun 30, 2011 at 1:52 PM, W5UXH <[hidden email]> wrote: >>>> > I looked at the MP3 file using Goldwave. It appears to me that the "12 >>>> KHz" >>>> > component is present only during the tics, not continuously. >>>> > >>>> > The tic period is roughly 270 msec (I have no idea what the tic is of >>>> > course). I zoomed in to a single tic (see PDF of images at the link >>>> > below). It appears that each tic has a very distinct pattern seen in >>>> the >>>> > individual samples which I suspect is the 12 KHz energy. >>>> > >>>> > I have no idea what any of this means. >>>> > >>>> > 73, >>>> > >>>> > Chuck, W5UXH >>>> > Las Cruces, NM >>>> > >>>> > >>>> https://sites.google.com/site/k3lineoutrecordings/ab3ls-mp3-file-analysis >>>> > Images and comments from Goldwave view of the MP3 file >>>> > >>>> > >>>> > Guy, K2AV wrote: >>>> >> >>>> >> Hi Geoff, below... >>>> >> >>>> >> On Thu, Jun 30, 2011 at 9:24 AM, Geoff Wolf AB3LS >>>> >> <[hidden email]> wrote: >>>> >>> And, for even more information, I analyzed the audio that I recorded >>>> and >>>> >>> the >>>> >>> squeal is right around 12Khz. It peaks at -48dB (louder than the QSK >>>> >>> relay >>>> >>> clicking) >>>> >>> >>>> >>> http://imgur.com/V8o5t - image of the analysis >>>> >>> >>>> >>> AB3LS >>>> >> >>>> >> With your image I realize I had been making some assumptions. I need >>>> >> to fill in some details... >>>> >> >>>> >> Are you listening to the audio in earphones or are you hearing it in >>>> >> the free air. I had been assuming listening with your ears only in >>>> >> free air to miscellaneous sound in the neighborhood of the K3. >>>> >> >>>> > >>>> > >>>> > -- >>>> > View this message in context: >>>> http://elecraft.365791.n2.nabble.com/K3-KPA100-Squeal-tp6518460p6534295.html >>>> > Sent from the Elecraft 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 >>>> > >>>> ______________________________________________________________ >>>> 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 >> > 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 |
Re: K3: KPA100 Squeal
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In reply to this post by AB3LS
Geoff,
It struck me when the squeal was first mentioned that something might be arcing over. If I understand correctly the squeal appears only when the 100w TX amp is - which narrows the search if arcing is the cause. If the 12 KHz squeal is present only when a tic is generated, and if arcing is the cause of the squeal, then a possible reason why this occurs is that the voltage in some circuit is ramping up to a voltage every 270 msec sufficient to cause something to arc over, which is heard as a tic plus squeal. It might be worth looking inside your K3 in a dark room. 73, Geoff GM4ESD On Friday, July 01, 2011 at 6:24 AM, Geoff Wolf AB3LS wrote: > This is a brand new K3 that I assembled about a month ago. The Serial > Number > is 5517. > > I have been using an Astron SS-25A power supply with this which is indeed > a > switcher. I have a battery that I'll be hooking up to it to see if this is > still a problem. >> On Thu, Jun 30, 2011 at 1:52 PM, W5UXH <[hidden email]> wrote: >> > I looked at the MP3 file using Goldwave. It appears to me that the "12 >> KHz" >> > component is present only during the tics, not continuously. >> > >> > The tic period is roughly 270 msec (I have no idea what the tic is of >> > course). I zoomed in to a single tic (see PDF of images at the link >> > below). It appears that each tic has a very distinct pattern seen in >> > the >> > individual samples which I suspect is the 12 KHz energy. ______________________________________________________________ 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 get this while in TX test mode, 5W, 100W, anything.
And yes this squeal is only present when the 100W amp is physically installed (KPA nor or not inst in the config menu) The squeal is present constantly when in TX mode. The ticking I was describing was keying up the radio in QSK CW with some dits and dahs. There's a pretty profound click between RX and TX. If I key the radio up in LSB in TX test mode the squeal is present 100% of the time while in TX, no matter if there's modulation, power going out, etc. I'll do my best to see if anything is arcing. And to an unnamed comment earlier on, I can hear this squeal at the other end of a decent sized room, I'm not making this stuff up. AB3LS > > On Fri, Jul 1, 2011 at 1:37 PM, Geoffrey Mackenzie-Kennedy < > [hidden email]> wrote: > >> Geoff, >> >> It struck me when the squeal was first mentioned that something might be >> arcing over. If I understand correctly the squeal appears only when the >> 100w TX amp is - which narrows the search if arcing is the cause. >> >> If the 12 KHz squeal is present only when a tic is generated, and if >> arcing is the cause of the squeal, then a possible reason why this occurs is >> that the voltage in some circuit is ramping up to a voltage every 270 msec >> sufficient to cause something to arc over, which is heard as a tic plus >> squeal. >> >> It might be worth looking inside your K3 in a dark room. >> >> 73, >> Geoff >> GM4ESD >> >> >> >> On Friday, July 01, 2011 at 6:24 AM, Geoff Wolf AB3LS wrote: >> >> This is a brand new K3 that I assembled about a month ago. The Serial >>> Number >>> is 5517. >>> >>> I have been using an Astron SS-25A power supply with this which is indeed >>> a >>> switcher. I have a battery that I'll be hooking up to it to see if this >>> is >>> still a problem. >>> >> >> >> On Thu, Jun 30, 2011 at 1:52 PM, W5UXH <[hidden email]> >>>> wrote: >>>> > I looked at the MP3 file using Goldwave. It appears to me that the >>>> "12 >>>> KHz" >>>> > component is present only during the tics, not continuously. >>>> > >>>> > The tic period is roughly 270 msec (I have no idea what the tic is of >>>> > course). I zoomed in to a single tic (see PDF of images at the link >>>> > below). It appears that each tic has a very distinct pattern seen in >>>> > the >>>> > individual samples which I suspect is the 12 KHz energy. >>>> >>> >> >> >> >> >> > 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
Geoffrey Wolf
AB3LS University of Pittsburgh '14 grw20@pitt.edu liltechdude13@gmail.com http://www.ab3ls.com |
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I've sent an email off to Elecraft about this and I'll be sure to update the
list here with what I hear back. Thanks for the advice guys, AB3LS On Fri, Jul 1, 2011 at 9:51 PM, Geoff Wolf AB3LS <[hidden email]>wrote: > I get this while in TX test mode, 5W, 100W, anything. > > And yes this squeal is only present when the 100W amp is physically > installed (KPA nor or not inst in the config menu) > > The squeal is present constantly when in TX mode. The ticking I was > describing was keying up the radio in QSK CW with some dits and dahs. > There's a pretty profound click between RX and TX. If I key the radio up in > LSB in TX test mode the squeal is present 100% of the time while in TX, no > matter if there's modulation, power going out, etc. > > I'll do my best to see if anything is arcing. > > And to an unnamed comment earlier on, I can hear this squeal at the other > end of a decent sized room, I'm not making this stuff up. > > AB3LS > >> >> On Fri, Jul 1, 2011 at 1:37 PM, Geoffrey Mackenzie-Kennedy < >> [hidden email]> wrote: >> >>> Geoff, >>> >>> It struck me when the squeal was first mentioned that something might be >>> arcing over. If I understand correctly the squeal appears only when the >>> 100w TX amp is - which narrows the search if arcing is the cause. >>> >>> If the 12 KHz squeal is present only when a tic is generated, and if >>> arcing is the cause of the squeal, then a possible reason why this occurs is >>> that the voltage in some circuit is ramping up to a voltage every 270 msec >>> sufficient to cause something to arc over, which is heard as a tic plus >>> squeal. >>> >>> It might be worth looking inside your K3 in a dark room. >>> >>> 73, >>> Geoff >>> GM4ESD >>> >>> >>> >>> On Friday, July 01, 2011 at 6:24 AM, Geoff Wolf AB3LS wrote: >>> >>> This is a brand new K3 that I assembled about a month ago. The Serial >>>> Number >>>> is 5517. >>>> >>>> I have been using an Astron SS-25A power supply with this which is >>>> indeed a >>>> switcher. I have a battery that I'll be hooking up to it to see if this >>>> is >>>> still a problem. >>>> >>> >>> >>> On Thu, Jun 30, 2011 at 1:52 PM, W5UXH <[hidden email]> >>>>> wrote: >>>>> > I looked at the MP3 file using Goldwave. It appears to me that the >>>>> "12 >>>>> KHz" >>>>> > component is present only during the tics, not continuously. >>>>> > >>>>> > The tic period is roughly 270 msec (I have no idea what the tic is of >>>>> > course). I zoomed in to a single tic (see PDF of images at the link >>>>> > below). It appears that each tic has a very distinct pattern seen in >>>>> > the >>>>> > individual samples which I suspect is the 12 KHz energy. >>>>> >>>> >>> >>> >>> >>> >>> >> > 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
Geoffrey Wolf
AB3LS University of Pittsburgh '14 grw20@pitt.edu liltechdude13@gmail.com http://www.ab3ls.com |
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In reply to this post by AB3LS
FYI I noticed the same on my #4717 kit (delivered last September). I normally use headphones so I never noticed it before. I believe ~12 kHz was getting into the DSP chain before the LPF mod to the DSP board was done so perhaps that's a clue. BTW I have no switching PS anywhere and this is definitely coming from the K3 itself. This would be VERY annoying to someone with good hearing in a quiet shack. I can minimize it by slight head movement (standing waves) but that's not a good solution. 73, Bill |
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I had some questions about this issue mailed to me.
Here's my update. Elecraft sent me a replacement KPA100 and KPA I/O board, of which I replaced myself. The new amplifier and I/O board fixed the problem. No more 12KHz resonation coming from the internals of the radio in test, low, and high power modes. The closest thing I can compare the sound to is the electrical resonation of a cathode ray tube in a TV, however, it's not as clean. Possibly a cold solder joint or bad connection between the amplifier and I/O board? I don't know. 73 DE AB3LS On Fri, Jul 29, 2011 at 4:29 PM, Bill W4ZV <[hidden email]> wrote: > > AB3LS wrote: > > > > No go. > > > > Hooked the radio up to a gel cel battery and we're still getting the > 12Khz > > junk coming from something and the clicking between TX and RX. > > > > I made a longer recording of the 'junk' and posted it. Cycled between TX > > and > > RX a few times using the manual TX button on the front. Then finished off > > with a few dits and dahs. All while in TX Test mode. > > > > > http://alien.liltechdude.com/files/index.php?dir=Recordings/&file=kpa3squealrev2.mp3 > > > > Anyone from Elecraft have anything on this? > > > > FYI I noticed the same on my #4717 kit (delivered last September). I > normally use headphones so I never noticed it before. I believe ~12 kHz > was > getting into the DSP chain before the LPF mod to the DSP board was done so > perhaps that's a clue. BTW I have no switching PS anywhere and this is > definitely coming from the K3 itself. > > This would be VERY annoying to someone with good hearing in a quiet shack. > I can minimize it by slight head movement (standing waves) but that's not a > good solution. > > 73, Bill > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/K3-KPA100-Squeal-tp6518460p6634869.html > Sent from the Elecraft 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 > 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
Geoffrey Wolf
AB3LS University of Pittsburgh '14 grw20@pitt.edu liltechdude13@gmail.com http://www.ab3ls.com |
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For those wondering, here's a link to a recording I made of the sound back
when I was having a problem: http://liltechdude.com/files/Recordings/kpa3squealrev2.mp3 I ran it through a spectral analyzer and produced this: squeal.png (image/png) 202K<https://mail.google.com/mail/?ui=2&ik=c5b17c1439&view=att&th=134f2e88d2107ef7&attid=0.1&disp=safe&realattid=f_gxkx14rr0&zw> 73 DE AB3LS On Wed, Jan 18, 2012 at 3:06 PM, Joe Harris <[hidden email]>wrote: > Thanks for the update, Geoff. I will contact Elecraft support to inquire > about a possible PA replacement. > > 73 > > Joe- N1QD > > > On Wed, Jan 18, 2012 at 2:39 PM, Geoff Wolf AB3LS <[hidden email] > > wrote: > >> I had some questions about this issue mailed to me. >> >> Here's my update. >> >> Elecraft sent me a replacement KPA100 and KPA I/O board, of which I >> replaced myself. >> >> The new amplifier and I/O board fixed the problem. No more 12KHz >> resonation >> coming from the internals of the radio in test, low, and high power modes. >> The closest thing I can compare the sound to is the electrical resonation >> of a cathode ray tube in a TV, however, it's not as clean. >> >> Possibly a cold solder joint or bad connection between the amplifier and >> I/O board? I don't know. >> >> 73 >> DE AB3LS >> >> On Fri, Jul 29, 2011 at 4:29 PM, Bill W4ZV <[hidden email]> wrote: >> >> > >> > AB3LS wrote: >> > > >> > > No go. >> > > >> > > Hooked the radio up to a gel cel battery and we're still getting the >> > 12Khz >> > > junk coming from something and the clicking between TX and RX. >> > > >> > > I made a longer recording of the 'junk' and posted it. Cycled between >> TX >> > > and >> > > RX a few times using the manual TX button on the front. Then finished >> off >> > > with a few dits and dahs. All while in TX Test mode. >> > > >> > > >> > >> http://alien.liltechdude.com/files/index.php?dir=Recordings/&file=kpa3squealrev2.mp3 >> > > >> > > Anyone from Elecraft have anything on this? >> > > >> > >> > FYI I noticed the same on my #4717 kit (delivered last September). I >> > normally use headphones so I never noticed it before. I believe ~12 kHz >> > was >> > getting into the DSP chain before the LPF mod to the DSP board was done >> so >> > perhaps that's a clue. BTW I have no switching PS anywhere and this is >> > definitely coming from the K3 itself. >> > >> > This would be VERY annoying to someone with good hearing in a quiet >> shack. >> > I can minimize it by slight head movement (standing waves) but that's >> not a >> > good solution. >> > >> > 73, Bill >> > >> > >> > -- >> > View this message in context: >> > >> http://elecraft.365791.n2.nabble.com/K3-KPA100-Squeal-tp6518460p6634869.html >> > Sent from the Elecraft 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 >> > >> ______________________________________________________________ >> 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 >> > > > > -- > Joe Harris, N1QD > ______________________________________________________________ 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
Geoffrey Wolf
AB3LS University of Pittsburgh '14 grw20@pitt.edu liltechdude13@gmail.com http://www.ab3ls.com |
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In reply to this post by AB3LS
FYI another update to this. I had the same audio squeal on #4717 and asked Gary AB7MY about it around the same time AB3LS's unit was in for repair. According to Dale K6ZP in Elecraft Service, the fix was:
"The KPA3 that is in for this problem has been fixed. The MMT3904 Q7 used as the 18 Mhz oscillator was turning off and on at ~ 15 khz rate, modulating the 18 Mhz. Replacing Q7 cleared the problem. " Since I had the same problem whenever my unit warmed up, Gary sent me a replacement for Q7. It requires removing the KPA3 module and Q7 is on the underside of the board. Q7 a small SMD transistor but is easy to access. You can replace it yourself if you're familiar with SMD work. I cut the existing device with nippers which made it easy to remove the 3 legs without damaging the PCB pads. After a good warmup calling 3C0E on 10m this morning my PA temp reached ~31C and I no longer have any squeal. BTW mine was always there after it got really warmed up...not just when I transmitted. I never noticed it before AB3LS' comment because I seldom never have my high isolation headphones off, but it would have definitely bothered someone with good hearing if they were using the speaker. 73, Bill W4ZV
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