[Elecraft] K3: KPA100 Squeal

[Guy Olinger K2AV]

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
<liltechdude13 at gmail.com> 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 <liltechdude13 at gmail.com>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 <olinger at bellsouth.net>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 <Chuck.Broadwell at gmail.com> 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
>>> >> &lt;liltechdude13 at gmail.com&gt; 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.
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>>
>>
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